Love is not exactly blind, at least for some people: Analytic cognitive style predicts romantic beliefs. BastienTrémolière, Hakim Djeriouat. Personality and Individual Differences, Volume 145, July 15 2019, Pages 119-131. https://doi.org/10.1016/j.paid.2019.03.025
Abstract: Recent research has highlighted the importance of people's cognitive style on the endorsement of epistemically suspect beliefs (e.g., beliefs in paranormal). The present studies extend that tradition of research to another form of epistemically suspect beliefs, that is, romantic beliefs. Using different cognitive style measures, we observed that an analytical cognitive style was associated with a decreased endorsement of romantic beliefs (Studies 1a–b) and the effect is qualified by conflict detection sensitivity (Studies 2a–b). Study 3 tested a structural equation model showing that cognitive style predicts romantic beliefs just as it predicts traditional epistemically suspect beliefs. Finally, an exploratory study (Study 4) unsuccessfully tested the possibility that differences in belief in the value of science might explain the association between cognitive style and romantic beliefs. Results are discussed in the light of the literature regarding the everyday consequences of cognitive style and the proposed psychological mechanisms underlying these associations.
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In their 2015's Current Directions in Psychological Science paper, Pennycook and colleagues (Pennycook, Fugelsang, & Koehler, 2015) reviewed evidence of the consequential nature of reasoning: the fact that differences in cognitive style predict a vast range of people's everyday beliefs and behaviors. Hence, cognitivestyle was found to predict reasoning activities (Toplak, West, & Stanovich, 2011;Trippas,Pennycook, Verde, & Handley, 2015), but it also extends beyond the reasoning domain: it predicts paranormal beliefs (e.g., religious beliefs, beliefs in ghosts, superstition), beliefs in conspiracy theories, beliefs in alternative medicine, moral values, prosociality, and also receptivity to non sensical sentences intended to convey the appearance of depth and sophistication (also known as ‘pseudo-profound bullshit’). In the present research, we focusonanother aspect of people's daily life that maybe associated with cognitive style, that is, romantic beliefs. Although romantic beliefs have never been given consensual definition, some of their dimensions are clearly to be thought of as epistemically suspect. Should it be the case, cognitive style is likely to predict these beliefs as well.1. Cognitive style and (some of) its everyday consequences. The definition of cognitive style (or thinking disposition) commonly draws on the distinction made by the dual process theories of thinking about the way people reason, judge, and decide (Evans,2008;Evans&Stanovich,2013;Kahneman, 2011). Although there are different dual process models (Epstein, 1994;Evans & Stanovich, 2013;Kahneman,2011; Sloman,1996),they all share the core idea that human thinking consists of two fundamentally different types of processing. Type 1 processing is assumed to be fast and almost effortless (i.e., it does not require much cognitive resources). By contrast, Type 2 processing is slow and greedy in cognitive resources (Evans & Stanovich, 2013). Many clever tasks are designed in such a way that an incorrect intuitive (Type 1) response springs immediately to mind, at the expense of a correct reflective (Type 2) response. In such cases, people need tooverridethatincorrectType1responsesoastocalculateandreachthecorrect Type 2 response. This disposition to rely on either of the twotypes of processing is labelled as cognitive style, defined as people'spropensity and willingness to think rather intuitively (Type 1 proces-sing)oranalytically(Type2processing).Importantly, cognitivestyleis not reducible to cognitive (or rea-soning)ability, although both dimensions positively correlate(Stanovich & West, 1998, 2000). Let us consider, for instance, the fa-mousbatandballbrainteasing(Frederick,2005)whichhasbeenus asaproxyofcognitivestyleincountlessstudies.Inthisproblem,a bat and ball cost $1.10 in total, and the bat costs $1 morethanball. Whenasked to indicate the price of the ball, a majority of people answer $0.10. Although that response springs rapidly to mind, it is incorrect. The correct, reflective response is $0.05. In this problem, the correct solving does not necessarily reflect differences in people's cognitive abilities (e.g., numerical, mathematical skills) as the calculation is very basic. Rather, the problem reflects people's cognitive style, and itscorrect solving captures primarily people's propensity to think analy-
tically (Toplak et al., 2011). In brief, cognitive style refers to an in-dividual's tendencyto rely on fast, automatic, and intuitivereasoning(Type 1 processing) versus slower, reflective, and analytic reasoning(Type 2 processing) in situations in which a misleading intuitive re-sponse cue is present. By contrast, cognitive ability captures people'sabilitytorelyonlogicandnormativereasoning(i.e.,toengageType2processing),intheabsenceofamisleadingintuitiveresponse.The fact that people who rely the most on Type 2 processing arethose who perform the best on reasoning tasks might not sound sur-prising,sincereasoningsuccessisabyproductofreflectivethinkinginsuch cases. Yet, it was recently found that cognitive style had con-sequencesthatextendbeyondthereasoningfield.Althoughitpredictsbeliefs and behaviors in a vast range of domains, such as morality(Garvey&Ford,2014;Pennycook,Cheyne,Barr,Koehler,&Fugelsang,2014b) or prosociality (Rand et al., 2014;Rand, Greene, & Nowak,2012), we focus, in regard to the present research, on the predictivevalueofcognitivestyleonbeliefslabelledasepistemicallysuspect.Epistemically suspect (or unwarranted)beliefs refer to beliefs thatconflict with common naturalistic conceptions of the world, and thatcannotbeexplainedviascienceorempirically-basedexplanations(seeLobato,Mendoza,Sims,&Chin,2014;Pennycooketal.,2015).Thesebeliefsareunfalsifiablestatements,ortheystandincontradictionwiththeconsensuallyadmittedprinciplesofreasonanddemonstrability.Forinstance,beliefsinghosts,afterlife,astrology,allbelongtothecategoryof epistemically suspect beliefs; and these beliefs have been recentlyshown tobe predictedbypeople's cognitivestyle(for ameta-analysisdevoted to exploring the relationship between cognitive style and re-ligiousbeliefs,seePennycook,Ross,Koehler,&Fugelsang,2016).Itwasshown,forinstance,thatmoreanalyticalpeople,whoscoredhighontheCognitiveReflectionTest(CRT;ashortmeasurecapturingpeople's cognitive style; that includes the bat and ball problem we il-lustratedpreviously;seeFrederick,2005)endorsedreligiousbeliefslessthan less analytic participants (Gervais & Norenzayan, 2012;Pennycook,Cheyne,Seli,Koehler,&Fugelsang,2012;Shenhav,Rand,& Greene, 2012). Similar conclusions were obtained using differentclassicreasoningtasksdesignedtomakeanintuitiveresponseconflictwith an analytic response: less religious people endorsed the analyticresponsethemostinabase-ratetask(Pennycooketal.,2014b,2012;Pennycook,Cheyne,Barr,Koehler,&Fugelsang,2014a)andinabelief-bias task (Pennycook, Cheyne, Koehler, & Fugelsang, 2013). By con-trast, analytic cognitive style predicts endorsement of evolutionaryaccountsofhumanorigins(Gervais,2015).Comparable measures and manipulations have led to similar con-clusions for other beliefs cast supernatural and/or epistemically un-warranted:analyticcognitivestylewasassociatedwithlowerlevelsofbeliefs in conspiracy theories (Swami, Voracek, Stieger, Tran, &Furnham, 2014) and paranormal beliefs (e.g., beliefs in ghosts, tele-pathy,omens)(Pennycooketal.,2012;Svedholm&Lindeman,2013).In that vein, less analytic people are more likely to attribute super-natural causation to experimentally controlled, but at first glance un-cannyexperiences(Bouvet&Bonnefon,2015;seealsoRoss,Hartig,&McKay,2017).Whetheritbetranscendentalorimmanent,allthesebeliefsshareacommonfeature:theyfallintothedomainofunfalsifiableassumptions.In thepresent paper, we areinterested in another type ofbeliefs thathavethepotentialtobecastasepistemicallysuspect,thatis,romanticbeliefs. The interest of examining cognitive style in relation to thesebeliefsisthat,albeitbaseless,theprocessunderlyingthemanifestationsoflovecanbeelucidatedbyscientificorempiricalobservations(e.g.,attachment in mammals;neurochemistry of attraction). Noteworthily,thereisadiscrepancybetweentheunderlyingprocessbywhichpeopleexperienceloveontheonehandandthesocio-culturalconstructionofthese experienceson theotherhand.Importantly,romantic love,per-tainstothelatter.Further,itisacategoryofbeliefswhichalmostev-erybody has ever experienced, by contrast to other epistemically sus-pect beliefs (e.g., religious beliefs, conspiracy theories, etc.). Thiscategory of beliefs is part of personal phenomenal experience, whichexcludesanyreferencetoexternalpowerfulentitiesonwhichtoinvestdevotion,admiration,orfear.Inthisperspective,thepresentresearchquestions the possibility that cognitive style is also associated withdifferencesintheendorsementofbaselessbeliefsofintrinsicnature.2. RomanticloveandconflictdetectionAlthough there is no consensual definition, it is proposed that ro-mantic love includes but is not reducible to passion (i.e., the physio-logicalarousalunderlyingattraction;Sternberg,1986).Itisthoughttobeaculturaluniversal(Hatfield&Rapson,2006;Jankowiak&Fischer,1992),anditservesanevolutionaryfunctionofsexualselection(Buss,2003) and pair-bond attachment (Miller, 2001). Beyond basic biolo-gicalneeds,romanticlovealsoseemstoservesocialfunctions,amongwhichcreatingandmaintainingmaritalbondsandunitingkingroupsofrespectivepartners(Rosenblatt,1967).Romanticloveisinthesocialrealm mostly expressed in terms of a set of beliefs rather than as abiological phenomenon (Weaver & Ganong, 2004). Understandably,romantictales,songs,andpoetriesaredeeplyrootedinhumancultures,and people daily life is filled with romantic narratives (Weaver &Ganong,2004).Culturalportrayalofromanticloverecurrentlyreferstothenotionsof love predestination (Franiuk, Cohen, & Pomerantz, 2002), love atfirstsight(Tanner,Haddock,Zimmerman,&Lund,2003)andtherightone mate (Signorielli, 1997). Consistent with these notions,SprecherandMetts(1999)haveproposedthatromanticbeliefsrefertotheideathat‘loveatfirstsightispossible,thattherecanbeonlyonetruelove,thattruelovelastsforever,thatthebelovedisperfectineveryrespect,and that true love can overcome all obstacles’ (p. 835;Sprecher &Metts, 1999), see also (Cunningham & Antill, 1981;Knox Jr &Sporakowski,1968;Peplau&Gordon,1985).1People, especially young ones, rely proactively on cultural trans-mission of romantic narratives to educate themselves about love(Bachen & Illouz, 1996). For instance, classic western fairy tales orromantic movies create prescriptive models structuring widespreadrelationships schemas and scripts (Bower, Black, & Turner, 1979;Holmberg & MacKenzie, 2002). Accordingly, people become ac-quainted with what to be expected in events related to romantic re-lationshipsandthenecessarystagesfromitsinitiationtoitsprojectedpleasing outcomes (e.g., marriage, children; seeHolmberg &MacKenzie, 2002). These internalized scripts have been evidenced toframetheenactmentofrelationship-relevantbehaviorsandtofacilitaterelational construction in a friendly manner as well as relationshipswell-being when personal scripts dovetail with normative scripts(Wilson&Capitman,1982).Theculturally-shapedstructurationofro-mantic beliefs generates various consequences on love, commitmentandrelationshipssatisfaction.Thereisevidencethatromanticbeliefs,fostered by unrealistic optimism and positive illusions, strengthen re-lationshipsdurationandquality(Knee,1998;Murray&Holmes,1997);and this trend has been longitudinally evidenced (Sprecher & Metts, 1989).Alternatively,someresearchhasemphasizedthedysfunctionalcharacter of these beliefs as they create a gap between preconceivedstandardsof‘perfectrelationship’andreality.Thisexpectationgaphasthepotentialtodecreaserelationshipquality(Baucom&Epstein,1990)and can be associated with inadequate problem-solving responses inrelationships (Metis & Cupach, 1990). These beliefs may lead to anelevated incidence of marital distress (N.Epstein, Pretzer, & Fleming,1987) and decreased expectations that any dialogue designed to fixrelationshipsproblemsormaritaltherapycanbesuccessful(Epstein&Eidelson,1981).Importantly,thereisnoscientificevidencefortheexactitudeofthegeneral claims as depicted bySprecher and Metts (1999). Examiningromanticlovethroughtheperspectiveofrationalityhasoccupiedalargesegmentofthephilosophicaldebates.ThephilosopherPascalinPensées(Pascal,1670/1976)advocatedthatlovedoesnotpertaintothecategoryofreasonallowingthediscoveryofdemonstrabletruth.Bycontrast,loveis thought of as a class of sentiments related to a form of universalknowledgewhichdispenseswithrationalthought.Muchmorerecently,some authors have even considered some of unrealistic beliefs aboutrelationships as irrational (Ellis, 1986;Gündogdu, Yavuzer, & Karatas,2018),partlybecausetheystemfromrigidandpreconceivedunrealisticschemes (e.g., “partners cannot change”, “mindreading is expected”)(Epstein&Eidelson,1981).Itisthenpossiblethatsomeromanticbeliefsqualifyasunwarrantedorepistemicallysuspectbeliefs.Thequestionremains astowhysomepeople hold thesebeliefs.Apromising way of addressing this issue is to rely on a cognitive ex-planation.Romanticnarrativesmightderivefromcognitivebiasessuchasoptimismbias(seeWeinstein&Klein,1996)orwishfulthinking(seeBastardi, Uhlmann, & Ross, 2011). Perhaps, some people nurture thehope of experiencing an ethereal love story or think that love dis-appointment would not concern them. If these beliefs is rooted incognitivebiases,thenpeoplemorepronetobiasesandfallacieswouldbe more likely to endorse romantic beliefs. In this perspective, thecognitivemechanismspromptingpeopletosubscribeorrejectromanticbeliefsmighthavetodowithcognitiveconflictdetection(forareviewonconflictdetection,seeDeNeys,2014).Inanutshell,conflictemergeswhenever Type 2 processing (necessary to correctly endorse logico-probabilistic principles) stands in contradiction to Type 1 processing(whichreliesonpersonalexperienceandbeliefs).Insuchsituations,theType 2 processing system is needed to overcome the belief-based re-sponse generated by the Type 1 processing system.2Multiple studieshave shown, however, that people regularly fail to override this cog-nitive conflict (e.g.,De Neys & Glumicic, 2008;Evans, 2003, 2008;Kahneman, 2011), just as it is the case in the bat and ball problemwhich we discussed earlier; further, it was recently found individualdifferencesinthepropensitytodetectconflictduringreasoningactiv-ities(Frey,Johnson,&DeNeys,2018).Thatis,somepeoplearemorelikelytodetectthenoverridecognitiveconflictthanothers.There is evidence that analytical cognitive style predicts lowerepistemicallysuspectbeliefs,inthecontextreligiousbeliefs,becauseofahigherpropensitytodetectconflict(Pennycooketal.,2014a,2013).Within the context of religion, conflict refers to the incompatibilitybetween the way human cognitive armature is designed to grasp thephysical world and the presence of supernatural entities or presumedhidden forces that transcend them (Atran & Norenzayan, 2004). Forexample,acknowledgingtheexistenceofectoplasmscapableofpassingindiscriminately through physical objects escape universal cognitiveprinciples(Pennycooketal.,2014a),andwouldreflectfailureincon-flict detection. Consistent with this possibility, Pennycook and collea-gues observed that performance on conflict reasoning problems (inwhichaType1responseisconflictingwithaType2response)predictsendorsementofreligiousbeliefs,withparticipantsperformingwellonthe problems being those who endorsed religious beliefs the least.Consistent with the conflict detection account, performance on noconflict problems (in which a Type 1 and a Type 2 response are con-gruent)wasnotassociatedwithreligiousbeliefs.Theseresultsarealsosupportedbyneuroimagingstudies.Activationoftheanteriorcingulatecortex (ACC), a critical brain region for conflict detection (Botvinick,Cohen, & Carter, 2004), has been shown to be negatively associatedwithreligiousbeliefs(Inzlicht&Tullett,2010).Conflict,inthecontextofromanticism,wouldresideintherationalreluctance to acknowledge the notions of soul mate, perfect mate,eternallove,andtheideathatloveisimbuedwithamysticalforcethathelps alleviate obstacles or conquer all. Essentially, conflict detectionhas itsimportanceregardingromantic narrativesbecauseoftheir ste-reotypical nature (Dion & Dion, 1973). For instance, the belief thatthere is ‘one and only one’ love is conflicting with the scientific evi-dence that polygyny is a natural component of mammals (includinghumanbeings;seeBarash&Lipton,2002).Besides,thebeliefthatlovelastsforevermaybeconsideredasaformofbaserateneglect.Forin-stance, some single and married people tend to rate their divorcelikelihood as considerably lower than population base rates (Fowers,Lyons,Montel,&Shaked,2001).Itwasevenobservedthansomepeopleheldthatthereisnochanceofdivorcedespitetheevidencethatatleasthalf of marriages terminated in divorce at the time of the study (seeFowersetal.,2001).3. ThecurrentresearchStudying the psychological processes associated with the endorse-mentofromanticnarrativesisofimportanceastheyareapivotalde-terminant of the relational construction, with important societal im-plications regarding intimate relations; further, their endorsement issometimesconducivetonegativeoutcomes.Romanticbeliefsalsoseemtosharesimilitudeswithmoretraditionalepistemicallysuspectbeliefs(e.g.,beliefsinparanormal)whichbringstraightforwardexplanationsof the world (Norenzayan & Gervais, 2013), and are thus easilyspreadableinthesocialsphere(Mercier,Majima,&Miton,2018).The current literature linking people's cognitive style to traditionalepistemically suspect beliefs has demonstrated that a more analyticthinking activity was the price for disqualifying these beliefs(Norenzayan&Gervais,2013).Romanticbeliefs,asepistemicallysuspectbeliefs,areintuitivelyappealingbecausetheymatchculturalvaluesre-garding romantic relational construction (schema, scripts and rituals)andbecausetheyserveahopeful,palliativepurpose.Becauseromanticnarrativesarewell-knownandmostpeoplehavealreadyexperiencedorhope to experience a romantic relationship, we seek to understand ifmore analytic people disregard these beliefs more than less analyticpeople,justastheywouldrejectanyotherepistemicallysuspectbeliefs.Suchaninvestigationwouldbeagoodtesttoseewhetherpeoplewithhigher rational dispositions would resist these powerful, universallywidespread beliefs. If this is the case, then we would observe that,whatever the differential nature of these specific beliefs, a rationalmindsetisassociatedwithareluctanceofthesebeliefs.Intheend,weseethepresentstudyasarelevantcomplementarytestoftheconsequencesof reasoning style, affording a sharper examination of the dual processaccountofepistemicallysuspect(dis)beliefs.Straightforwardpredictionsarederivableregardingtheassociationbetween cognitive style and endorsement of romantic beliefs, in thesamewayascognitivestylepredictsanyepistemicallysuspectbeliefs:the more analytical (intuitive) people are, the less (more) they sub-scribetoromanticbeliefs.Inasetof6studies,weexplorethepossibleassociationofcognitivestyleandromanticbeliefs.Importantly,wewilluse multiple, different measures (performance tests, self-report mea-sures)soastoensureboththerobustnessofthepredictedassociationandtheinternalvalidityofourstudies.Studies1aand1btestdiffer measures of cognitive style, which have been extensively used in thefieldofreasoningpsychology,toexplorethepredictedassociationwithromanticbeliefs.Studies2aand2btestthepossibilitythatthisexpectedassociation between cognitive style and romantic beliefs is primarilyexplained by individual differences in conflict detection. Study 3 ex-ploresthepossibilitythattherelationshipsbetweencognitivestyleandromantic beliefs on the one hand, and between cognitive style andparanormal beliefs on the other hand, are concomitant. Study 4 ex-ploresapotentialexplanationoftheassociationbetweencognitivestyleandromanticbeliefs,thatis,theroleofbeliefsinthevalueofscience.
11. GeneraldiscussionIn the vein of the recent studies investigating everyday con-sequences of people's cognitive style, we explored the way it affectsanotheryetunexploredepistemicallysuspectbelief,romanticbeliefs.Ina set of experiments, we showed that cognitive style impacted onpeople'sendorsementofromanticbeliefs:lessanalyticpeopleendorsethesebeliefsmore.Thisresultwasreplicatedusingdifferentmeasures andtests,providingrobustevidenceofthephenomenon.Importantly,our results showed that the predictive power of cognitive style heldeven after controlling for cognitive ability (Studies 2a–b), putting thelightonthedecisiveroleofconflictdetection.Study3showedparalleleffects of cognitive style on romantic beliefs and paranormal beliefs.Study 4 explored a possible explanation of the relationship betweencognitive style and romantic beliefs, that is, that intuitive people be-lieve more in romanticism because they trust less scientific evidence.Theobtainedpatternofcorrelations,however,wasdifficulttodecipher,in particular regarding the positive association between belief in sci-ence and belief in romanticism (when cognitive style was positivelyassociated with belief in science, and negatively associated with ro-manticism). Because that study was exploratory, we refrained fromspeculating too much about the possible candidate explanations thatwouldfitthispatternofresults.ItisworthnotingthatNeedForCognition(NFC),usedasaproxyforcognitivestyle(Studies1band2),wasneverassociatedwithromanticbeliefs (and additional unreported analyses showed that NFC neverpredictedromanticbeliefsevenwhenexcludingFIfromtheanalyses).Faith in Intuition, the other subscale of the Rational-Experientialthinkingmeasure(S.Epsteinetal.,1996)didmuchbetter,beingsys-tematically positively associated with the endorsement of romanticbeliefs.Onabrighternote,theActivelyOpen-mindedThinking(AOT)measure showed strong and consistent associations with romantic be-liefs.Takentogether,theseresultssupporttheimportantroleofcognitivestyleindifferentsetsofeverydaybeliefs.Theimportanceofcognitivestyle lies initsincremental valueaboveandbeyond cognitive ability.Cognitive ability, however, was consistently proven to be much lesspredictivethancognitivestyle(inthreeoutfourofourstudies,cogni-tive ability did not predict romantic beliefs when cognitive style wascontrolled,similarlytotheobservationofPennycooketal.,2012).Although secondary in regard to our current purpose, one wouldpossibly find surprising that we systematically distinguished betweenperformance tests (CRT) and self-report measures of cognitive style(e.g.,AOT).Inouranalyses,wealmostalwaysexploredonefacetwhilecontrolling for the other (Studies 2–4). For instance, one may haveexpected that the CRT (which captures both cognitive style and cog-nitive ability;Pennycook & Ross, 2016) loses its predictive valuewhenever AOT (which captures cognitive style) and Numeracy/BRN(whichcapturecognitiveability)areincludedascovariates(andvice-versawithAOT,leavingNumeracy/BRNaside).Ourresultsshowed,bycontrast,thatthetwofacetsofcognitivestyledonotcompletelyoverlapandremainsignificantwhencontrollingforeachother.Itsuggeststhatthese classic measures of cognitive style, although part of a uniformconcept, each explain a proportion of unshared variance to a givencommonphenomenon.Additional remarks would concern the tasks we used to infer theroleofconflictdetection.Weacknowledgethattheasymmetrybetweenthe Cognitive Reflection Test and the tasks used to assess cognitiveability (numeracy and Base Rate neutral) may lead us to nuance ourclaim regarding conflict detection. This issue was also addressed byPennycooketal.(2014b)whonotedthatpossiblyanyofthetasksusedin the field purely captures either cognitive style or cognitive ability.Possibly,allthetaskscapturebothcognitivestyleandcognitiveability,buttodifferentextents(beingdisposedtothinkanalyticallywillnotbeefficient if one does not have therequisite cognitive abilities, and, si-milarly,beingcognitivelyabletofindasolutionwillbeuselessifonedoesnothavethewillingnesstoengageanalyticthinking).Intheend,one will ultimately never know whether one fully controlled the cog-nitive ability dimension. Nonetheless, the heterogeneity of the mea-sures we used, as well as the consistency of our results, both providerobustevidencethatweisolated,atleasttoacertaindegree,thecon-flictdetectionmechanism.Atanotherlevel,onemayworryaboutthereliability of theCognitive ReflectionTest, asit has been heavilyem-ployed on online crowdsourcing platforms, making the search andfindingofparticipantsnaivetothetestdifficult.Althoughwedidnotcontrol for familiarity, there is recent evidence showing that the pre-dictive validity of the CRT is robust to multiple exposure (Bialek &Pennycook,2017),rulingoutthatpotentialissue.Romanticloveisapeculiar andcomplexintrinsicsensationthat amajority of people, including analytic people, have already experi-enced. In this perspective, a possible explanation of the associations we found might be that romanticism calls for a different kind of knowledge, a sort of intuitionistic truth,whichdoesnotfitwiththerationalmindset, hence its rejection in people who adopt a rational mode of apprehension of the world.Romanticloveoffersagoodavenueofre-search for understanding the role cognitive style plays on people's endorsementof irrationalbeliefs.It is worth noting that we are not making any value judgment re-gardingwhetherpeople shouldorshould not favor ananalytic cognitive style over an intuitive one. Although many reasoning researcheswould pointtotheneedofrelyingonanalyticprocessingoverintuitiveone,thereisevidencethatintuitiondoesbetterthanreflectionincer-taincontexts (see Dijksterhuis,2004;Kruglanski&Gigerenzer,2011),raising the need to consider intuition as a useful psychological pro-cessing as well. We are not making any value judgments, either, regardingwhetherpeopleshouldorshouldnotendorseromanticbeliefs.Regardless the negative associations between cognitive style and romantic beliefsweobservedinourstudies,onehastonotethatromanticbeliefs have important functions in partnership. Romanticism is considered a cultural universal (Hatfield&Rapson,2006), suggesting that it has possibly evolved across cultures to facilitate pair-bonding (Fisher,2012). Romanticbeliefs(measuredvia the same romantic beliefs scale weusedinthepresentresearch),forinstance, were found to be highly associated with relationship quality (love, satisfaction, and commit-mentSprecher&Metts,1999).The study of the consequences of cognitive style on real-world attitudes and behaviors are still very recent and as a consequence scarce. As Pennycook et al. (2015)stated, research is needed to identify themany domains in which cognitive style may operate; our study is di-rectly aligned with that purpose. Undoubtedly, any belief or attitude cast supernatural or epistemically unwarranted may be associated with cognitive style, as was the case with paranormal beliefs (Pennycooket al., 2012;Svedholm & Lindeman, 2013), beliefs in conspiracy theories (Swamietal.,2014) or the attribution of supernatural causation of uncanny experiences (Bouvet&Bonnefon,2015). Of great importance is that cognitive style does not merely predictasetofeverydaybeliefs, but it also extends to the explanationofpublicutility behaviors, such as in the domain of prosociality and cooperation(Randetal.,2012,2014).Suchrecentdiscoveriesconfirmtheneedtodeisolatethefieldofrea-soning psychology so at to put it at the service of humanity (seeBonnefon, 2013), and promote, in parallel, the usefulness to deeperexplore the beliefs, attitudes, and everyday behaviors that are asso-ciated with reasoning, many of which are undoubtedly yet to be dis-covered.
Friday, March 29, 2019
Efficacy of anti‐inflammatory treatment on major depressive disorder or depressive symptoms: They improved antidepressant treatment; studies need to include longer follow‐up, identify optimal doses & patients than may benefit
Efficacy of anti‐inflammatory treatment on major depressive disorder or depressive symptoms: meta‐analysis of clinical trials. O. Köhler‐Forsberg et al. Acta Psychiatrica Scandinavica, March 4 2019. https://doi.org/10.1111/acps.13016
Abstract
Background: No study has gathered evidence from all randomized clinical trials (RCTs) with anti‐inflammatory drugs measuring antidepressant effects including a detailed assessment of side‐effects and bias.
Methods: We performed a systematic review identifying RCTs published prior to January 1, 2018, studying antidepressant treatment effects and side‐effects of pharmacological anti‐inflammatory intervention in adults with major depressive disorder (MDD) or depressive symptoms. Outcomes were depression scores after treatment, remission, response, and side‐effects. Pooled standard mean differences (SMD) and risk ratios (RR) including 95% confidence intervals (95%‐CI) were calculated.
Results: We identified 36 RCTs, whereof 13 investigated NSAIDs (N = 4214), 9 cytokine inhibitors (N = 3345), seven statins (N = 1576), 3 minocycline (N = 151), 2 pioglitazone (N = 77), and 2 glucocorticoids (N = 59). Anti‐inflammatory agents improved depressive symptoms compared to placebo as add‐on in patients with MDD (SMD = −0.64; 95%‐CI = −0.88, −0.40; I2 = 51%; N = 597) and as monotherapy (SMD = −0.41; 95%‐CI = −0.60, −0.22; I2 = 93%, N = 8825). Anti‐inflammatory add‐on improved response (RR = 1.76; 95%‐CI = 1.44–2.16; I2 = 16%; N = 341) and remission (RR = 2.14; 95%‐CI = 1.03–4.48; I2 = 57%; N = 270). We found a trend toward an increased risk for infections, and all studies showed high risk of bias.
Conclusion: Anti‐inflammatory agents improved antidepressant treatment effects. Future RCTs need to include longer follow‐up, identify optimal doses and subgroups of patients that can benefit from anti‐inflammatory intervention.
Check also
Bhanu Sharma Brian W.Timmons
https://www.sciencedirect.com/science/article/abs/pii/S0031938418307649
Abstract
Background: No study has gathered evidence from all randomized clinical trials (RCTs) with anti‐inflammatory drugs measuring antidepressant effects including a detailed assessment of side‐effects and bias.
Methods: We performed a systematic review identifying RCTs published prior to January 1, 2018, studying antidepressant treatment effects and side‐effects of pharmacological anti‐inflammatory intervention in adults with major depressive disorder (MDD) or depressive symptoms. Outcomes were depression scores after treatment, remission, response, and side‐effects. Pooled standard mean differences (SMD) and risk ratios (RR) including 95% confidence intervals (95%‐CI) were calculated.
Results: We identified 36 RCTs, whereof 13 investigated NSAIDs (N = 4214), 9 cytokine inhibitors (N = 3345), seven statins (N = 1576), 3 minocycline (N = 151), 2 pioglitazone (N = 77), and 2 glucocorticoids (N = 59). Anti‐inflammatory agents improved depressive symptoms compared to placebo as add‐on in patients with MDD (SMD = −0.64; 95%‐CI = −0.88, −0.40; I2 = 51%; N = 597) and as monotherapy (SMD = −0.41; 95%‐CI = −0.60, −0.22; I2 = 93%, N = 8825). Anti‐inflammatory add‐on improved response (RR = 1.76; 95%‐CI = 1.44–2.16; I2 = 16%; N = 341) and remission (RR = 2.14; 95%‐CI = 1.03–4.48; I2 = 57%; N = 270). We found a trend toward an increased risk for infections, and all studies showed high risk of bias.
Conclusion: Anti‐inflammatory agents improved antidepressant treatment effects. Future RCTs need to include longer follow‐up, identify optimal doses and subgroups of patients that can benefit from anti‐inflammatory intervention.
Check also
The efficacy of anti-inflammatory treatment interventions on depression in individuals with major depressive disorder and high levels of inflammation: A systematic review of randomized clinical trials
https://www.sciencedirect.com/science/article/abs/pii/S0031938418307649
Finding meaning in the clouds: Illusory pattern perception predicts receptivity to pseudo-profound bullshit
Finding meaning in the clouds: Illusory pattern perception predicts receptivity to pseudo-profound bullshit. Alexander C. Walker et al. Judgment and Decision Making, Vol. 14, No. 2, March 2019, pp. 109-119. http://journal.sjdm.org/18/181212a/jdm181212a.html
Abstract: Previous research has demonstrated a link between illusory pattern perception and various irrational beliefs. On this basis, we hypothesized that participants who displayed greater degrees of illusory pattern perception would also be more likely to rate pseudo-profound bullshit statements as profound. We find support for this prediction across three experiments (N = 627) and four distinct measures of pattern perception. We further demonstrate that this observed relation is restricted to illusory pattern perception, with participants displaying greater endorsement of non-illusory patterns being no more likely to rate pseudo-profound bullshit statements as profound. Additionally, this relation is not a product of a general proclivity to rate all statements as profound and is not accounted for by individual differences in analytic thinking. Overall, we demonstrate that individuals with a tendency to go beyond the available data such that they uncritically endorse patterns where no patterns exist are also more likely to create and endorse false-meaning in meaningless pseudo-profound statements. These findings are discussed in the context of a proposed framework that views individuals’ receptivity to pseudo-profound bullshit as, in part, an unfortunate consequence of an otherwise adaptive process: that of pattern perception.
Keywords: pseudo-profound bullshit, bullshit receptivity, illusory pattern perception, irrational belief
1 Introduction
“Bullshit is everywhere.” – George Carlin
This statement may be truer today than ever before, as technological advances have allowed for information to spread faster and farther than ever before. Included in this expansion of information is likely an increase in peoples’ exposure to bullshit. While many people may believe that they can reliably detect and resist bullshit, empirical findings suggest otherwise (Pennycook, Cheyne, Barr, Koehler & Fugelsang, 2015a; Pennycook & Rand, 2018; Pfattheicher & Schindler, 2016; Sterling, Jost & Pennycook, 2016). For example, an initial investigation of people’s receptivity to pseudo-profound bullshit by Pennycook and colleagues (2015a) demonstrated how people frequently rate these superficially impressive yet vacuous statements as profound. Furthermore, studies have reported initial evidence for how receptivity to pseudo-profound bullshit relates to real-world beliefs, such as beliefs about political ideologies and candidates (Pfattheicher & Schindler, 2016; Sterling, Jost & Pennycook, 2016), conspiracy and supernatural beliefs (Pennycook et al. 2015a), and beliefs about the accuracy of “fake news” (Pennycook & Rand, 2018). Despite bullshit representing a real, prevalent, and consequential phenomenon, little research has been conducted on the topic. The current article furthers the investigation of pseudo-profound bullshit in two ways: First, we propose that peoples’ susceptibility to pseudo-profound bullshit arises in part as an unfortunate consequence of an otherwise adaptive behaviour, that of pattern perception; second, congruent with this proposal, we investigate whether individuals susceptible to endorsing illusory patterns are more receptive to pseudo-profound bullshit.
1.1 Pseudo-profound bullshit
Initial investigations of bullshit, specifically of the pseudo-profound variety, have utilized Frankfurt’s (2005) conception of bullshit as an absence of concern for the truth. That is, according to Frankfurt, bullshit is not about falsity but rather fakery; bullshit may be true, false, or meaningless, what makes a claim bullshit is an implied yet artificial attention to the truth. Consistent with this description of bullshit, Pennycook and colleagues (2015a) generated a list of superficially impressive statements that implied yet did not contain either truth or meaning by having a computer program randomly arrange a set of profound-sounding words in a way that maintained proper syntactic structure (see Dalton, 2016, for a comment, and Pennycook, Cheyne, Barr, Koehler & Fugelsang, 2016, for a response).
In addition to demonstrating peoples’ receptiveness to meaningless pseudo-profound bullshit statements, Pennycook and colleagues (2015a) revealed how various individual differences were associated with bullshit receptivity. Specifically, it was found that those more receptive to bullshit were less analytic thinkers (e.g., scored lower on the Cognitive Reflection Test), scored lower in measures of cognitive ability (e.g., the Wordsum test and Raven’s Advanced Progressive Matrices), and were more likely to hold religious, conspiratorial, and paranormal beliefs. Two mechanisms were proposed to explain participants’ endorsement of pseudo-profound bullshit. First, some participants were shown to possess a general tendency to afford any and all statements some level of profundity (e.g., mundane statements such as “Some things have very distinct smells”). The results of Pennycook and colleagues suggest that this gullible tendency towards ascribing profoundness to even the most mundane of statements is one component of bullshit receptivity. Second, individual differences in analytic thinking (as measured by the Cognitive Reflection Test and a “Heuristics and Biases” battery) were found to be associated with bullshit receptivity. Specifically, those with a propensity for analytic (as opposed to intuitive) thinking were found to be less receptive to pseudo-profound bullshit. Thus, another explanation put forth by Pennycook and colleagues is that individuals differ with regards to their ability to detect bullshit, with more analytic thinkers being more likely to detect and critically reflect on the presented pseudo-profound bullshit statements leading to lower ratings of profundity. The primary goal of this paper is to propose a third compatible mechanism to explain individual differences in receptivity to pseudo-profound bullshit: the illusory perception of patterns.
1.2 Illusory pattern perception
The ability to perceive patterns and form meaningful connections between stimuli in our environment is clearly evolutionarily advantageous (Beck & Forstmeier, 2007; Mattson, 2014; Shermer, 2011). For example, Mattson (2014) claims that superior pattern processing capabilities are essential for a variety of higher cognitive functions (e.g., imagination and invention) and likewise, credits these capabilities as fundamental to the technological progress humans have enjoyed. Relatedly, he argues that evolved superior pattern processing abilities are a primary reason why human cognition greatly exceeds the capabilities of lower species. Due to the adaptive nature of pattern perception, it has been claimed that we are the descendants of those best able to detect patterns (Shermer, 2011).
Nevertheless, our proclivity for detecting patterns comes with a cost, as we often find it difficult to distinguish between real and illusory patterns. Therefore, the same adaptive processes that allow us to perceive patterns and identify meaningful connections between stimuli in our environment also leads us to sometimes perceive illusory patterns and consequently endorse false beliefs about reality. However, when comparing the consequences of failing to detect a real and informative pattern with those of endorsing an illusory pattern, one of these errors may frequently loom larger than the other. For example, failing to connect a rustling in the grass with the presence of a dangerous predator has more dire consequences than mistakenly attributing movement in the grass to a predator and misguidedly escaping from a gust of wind. Using an evolutionary model, Biologist Foster and Kokko (2009) demonstrated how natural selection can favour strategies that involve the frequent endorsement of illusory patterns in order to ensure successful detection of meaningful patterns that offer large reproductive and survival benefits. Additionally, beliefs based on illusory patterns can even be advantageous if they disrupt aversive feelings, such as overwhelming thoughts of lacking control in an unpredictable world (Hogg, Adelman & Blagg, 2010; Whitson & Galinsky, 2008). This asymmetry of consequences between missing a real pattern and endorsing an illusory one is one reason humans are said to have evolved a “believing-brain” with a proclivity for pattern perception and a susceptibility to being fooled by illusory patterns (Beck & Forstmeier, 2007; Foster & Kokko, 2009; Shermer, 2011). Thus, not unlike the adaptive heuristics that guide decision-making, yet predictably lead to certain biases, pattern perception may represent an adaptive function at the heart of both rational and irrational beliefs about how stimuli are connected in the environments that we inhabit.
Illusory pattern perception includes the perception of connections between unrelated stimuli as well as the perception of patterns within random stimuli. One reason for the occurrence of illusory pattern perception is the fact that individuals often have difficulty accepting that ordered events can emerge from random processes. For example, when asked to produce random sequences, people often produce far more variation (and therefore fewer “runs”) than would be created by a truly random process (Falk & Konold, 1997). What follows, is that when people encounter random sequences that coincidentally maintain some order (e.g., symmetry in a series of coin tosses) they may ascribe a meaningful non-random process as its source (Gilovich, Vallone & Tversky, 1985).
People’s tendency to engage in illusory pattern perception has been shown to be associated with various irrational beliefs (Blackmore & Moore, 1994; Van Harreveld, Rutjens, Schneider, Nohlen & Keskinis, 2014; Van Prooijen, Douglas & Inocencio, 2018; Wiseman & Watt, 2006). For example, Van Prooijen, Douglas and Inocencio (2018), found that individuals who perceive more illusory patterns are also more likely to endorse conspiracy and supernatural beliefs. Related to this association between illusory pattern perception and irrational belief is the finding that lacking control increases illusory pattern perception (Van Harreveld et al., 2014; Whitson & Galinsky, 2008). Whitson and Galinsky (2008) demonstrate that those induced to feel a lack of control perceive more illusory patterns and engage in more conspiratorial and superstitious thinking. On the basis of this evidence they argue that feeling a lack of control in one’s environment is so aversive that individuals will often endorse illusory patterns and irrational beliefs in order to diminish feelings of lacking control and return to the more pleasant view that one’s environment is predictable. Consistent with this argument is additional evidence demonstrating that lacking control increases conspiracy (Sullivan, Landau & Rothschild, 2010; Van Prooijen & Acker, 2015) and supernatural beliefs (Kay, Gaucher, McGregor & Nash, 2010; Laurin, Kay & Moscovitch, 2008). Therefore, irrational beliefs may not only arise as the result of a believing-brain with a proclivity towards pattern perception, but also as a compensatory strategy that seeks to endorse patterns (illusory or not) in order to alleviate aversive states, such as feeling a lack of control in an unpredictable environment.
Abstract: Previous research has demonstrated a link between illusory pattern perception and various irrational beliefs. On this basis, we hypothesized that participants who displayed greater degrees of illusory pattern perception would also be more likely to rate pseudo-profound bullshit statements as profound. We find support for this prediction across three experiments (N = 627) and four distinct measures of pattern perception. We further demonstrate that this observed relation is restricted to illusory pattern perception, with participants displaying greater endorsement of non-illusory patterns being no more likely to rate pseudo-profound bullshit statements as profound. Additionally, this relation is not a product of a general proclivity to rate all statements as profound and is not accounted for by individual differences in analytic thinking. Overall, we demonstrate that individuals with a tendency to go beyond the available data such that they uncritically endorse patterns where no patterns exist are also more likely to create and endorse false-meaning in meaningless pseudo-profound statements. These findings are discussed in the context of a proposed framework that views individuals’ receptivity to pseudo-profound bullshit as, in part, an unfortunate consequence of an otherwise adaptive process: that of pattern perception.
Keywords: pseudo-profound bullshit, bullshit receptivity, illusory pattern perception, irrational belief
1 Introduction
“Bullshit is everywhere.” – George Carlin
This statement may be truer today than ever before, as technological advances have allowed for information to spread faster and farther than ever before. Included in this expansion of information is likely an increase in peoples’ exposure to bullshit. While many people may believe that they can reliably detect and resist bullshit, empirical findings suggest otherwise (Pennycook, Cheyne, Barr, Koehler & Fugelsang, 2015a; Pennycook & Rand, 2018; Pfattheicher & Schindler, 2016; Sterling, Jost & Pennycook, 2016). For example, an initial investigation of people’s receptivity to pseudo-profound bullshit by Pennycook and colleagues (2015a) demonstrated how people frequently rate these superficially impressive yet vacuous statements as profound. Furthermore, studies have reported initial evidence for how receptivity to pseudo-profound bullshit relates to real-world beliefs, such as beliefs about political ideologies and candidates (Pfattheicher & Schindler, 2016; Sterling, Jost & Pennycook, 2016), conspiracy and supernatural beliefs (Pennycook et al. 2015a), and beliefs about the accuracy of “fake news” (Pennycook & Rand, 2018). Despite bullshit representing a real, prevalent, and consequential phenomenon, little research has been conducted on the topic. The current article furthers the investigation of pseudo-profound bullshit in two ways: First, we propose that peoples’ susceptibility to pseudo-profound bullshit arises in part as an unfortunate consequence of an otherwise adaptive behaviour, that of pattern perception; second, congruent with this proposal, we investigate whether individuals susceptible to endorsing illusory patterns are more receptive to pseudo-profound bullshit.
1.1 Pseudo-profound bullshit
Initial investigations of bullshit, specifically of the pseudo-profound variety, have utilized Frankfurt’s (2005) conception of bullshit as an absence of concern for the truth. That is, according to Frankfurt, bullshit is not about falsity but rather fakery; bullshit may be true, false, or meaningless, what makes a claim bullshit is an implied yet artificial attention to the truth. Consistent with this description of bullshit, Pennycook and colleagues (2015a) generated a list of superficially impressive statements that implied yet did not contain either truth or meaning by having a computer program randomly arrange a set of profound-sounding words in a way that maintained proper syntactic structure (see Dalton, 2016, for a comment, and Pennycook, Cheyne, Barr, Koehler & Fugelsang, 2016, for a response).
In addition to demonstrating peoples’ receptiveness to meaningless pseudo-profound bullshit statements, Pennycook and colleagues (2015a) revealed how various individual differences were associated with bullshit receptivity. Specifically, it was found that those more receptive to bullshit were less analytic thinkers (e.g., scored lower on the Cognitive Reflection Test), scored lower in measures of cognitive ability (e.g., the Wordsum test and Raven’s Advanced Progressive Matrices), and were more likely to hold religious, conspiratorial, and paranormal beliefs. Two mechanisms were proposed to explain participants’ endorsement of pseudo-profound bullshit. First, some participants were shown to possess a general tendency to afford any and all statements some level of profundity (e.g., mundane statements such as “Some things have very distinct smells”). The results of Pennycook and colleagues suggest that this gullible tendency towards ascribing profoundness to even the most mundane of statements is one component of bullshit receptivity. Second, individual differences in analytic thinking (as measured by the Cognitive Reflection Test and a “Heuristics and Biases” battery) were found to be associated with bullshit receptivity. Specifically, those with a propensity for analytic (as opposed to intuitive) thinking were found to be less receptive to pseudo-profound bullshit. Thus, another explanation put forth by Pennycook and colleagues is that individuals differ with regards to their ability to detect bullshit, with more analytic thinkers being more likely to detect and critically reflect on the presented pseudo-profound bullshit statements leading to lower ratings of profundity. The primary goal of this paper is to propose a third compatible mechanism to explain individual differences in receptivity to pseudo-profound bullshit: the illusory perception of patterns.
1.2 Illusory pattern perception
The ability to perceive patterns and form meaningful connections between stimuli in our environment is clearly evolutionarily advantageous (Beck & Forstmeier, 2007; Mattson, 2014; Shermer, 2011). For example, Mattson (2014) claims that superior pattern processing capabilities are essential for a variety of higher cognitive functions (e.g., imagination and invention) and likewise, credits these capabilities as fundamental to the technological progress humans have enjoyed. Relatedly, he argues that evolved superior pattern processing abilities are a primary reason why human cognition greatly exceeds the capabilities of lower species. Due to the adaptive nature of pattern perception, it has been claimed that we are the descendants of those best able to detect patterns (Shermer, 2011).
Nevertheless, our proclivity for detecting patterns comes with a cost, as we often find it difficult to distinguish between real and illusory patterns. Therefore, the same adaptive processes that allow us to perceive patterns and identify meaningful connections between stimuli in our environment also leads us to sometimes perceive illusory patterns and consequently endorse false beliefs about reality. However, when comparing the consequences of failing to detect a real and informative pattern with those of endorsing an illusory pattern, one of these errors may frequently loom larger than the other. For example, failing to connect a rustling in the grass with the presence of a dangerous predator has more dire consequences than mistakenly attributing movement in the grass to a predator and misguidedly escaping from a gust of wind. Using an evolutionary model, Biologist Foster and Kokko (2009) demonstrated how natural selection can favour strategies that involve the frequent endorsement of illusory patterns in order to ensure successful detection of meaningful patterns that offer large reproductive and survival benefits. Additionally, beliefs based on illusory patterns can even be advantageous if they disrupt aversive feelings, such as overwhelming thoughts of lacking control in an unpredictable world (Hogg, Adelman & Blagg, 2010; Whitson & Galinsky, 2008). This asymmetry of consequences between missing a real pattern and endorsing an illusory one is one reason humans are said to have evolved a “believing-brain” with a proclivity for pattern perception and a susceptibility to being fooled by illusory patterns (Beck & Forstmeier, 2007; Foster & Kokko, 2009; Shermer, 2011). Thus, not unlike the adaptive heuristics that guide decision-making, yet predictably lead to certain biases, pattern perception may represent an adaptive function at the heart of both rational and irrational beliefs about how stimuli are connected in the environments that we inhabit.
Illusory pattern perception includes the perception of connections between unrelated stimuli as well as the perception of patterns within random stimuli. One reason for the occurrence of illusory pattern perception is the fact that individuals often have difficulty accepting that ordered events can emerge from random processes. For example, when asked to produce random sequences, people often produce far more variation (and therefore fewer “runs”) than would be created by a truly random process (Falk & Konold, 1997). What follows, is that when people encounter random sequences that coincidentally maintain some order (e.g., symmetry in a series of coin tosses) they may ascribe a meaningful non-random process as its source (Gilovich, Vallone & Tversky, 1985).
People’s tendency to engage in illusory pattern perception has been shown to be associated with various irrational beliefs (Blackmore & Moore, 1994; Van Harreveld, Rutjens, Schneider, Nohlen & Keskinis, 2014; Van Prooijen, Douglas & Inocencio, 2018; Wiseman & Watt, 2006). For example, Van Prooijen, Douglas and Inocencio (2018), found that individuals who perceive more illusory patterns are also more likely to endorse conspiracy and supernatural beliefs. Related to this association between illusory pattern perception and irrational belief is the finding that lacking control increases illusory pattern perception (Van Harreveld et al., 2014; Whitson & Galinsky, 2008). Whitson and Galinsky (2008) demonstrate that those induced to feel a lack of control perceive more illusory patterns and engage in more conspiratorial and superstitious thinking. On the basis of this evidence they argue that feeling a lack of control in one’s environment is so aversive that individuals will often endorse illusory patterns and irrational beliefs in order to diminish feelings of lacking control and return to the more pleasant view that one’s environment is predictable. Consistent with this argument is additional evidence demonstrating that lacking control increases conspiracy (Sullivan, Landau & Rothschild, 2010; Van Prooijen & Acker, 2015) and supernatural beliefs (Kay, Gaucher, McGregor & Nash, 2010; Laurin, Kay & Moscovitch, 2008). Therefore, irrational beliefs may not only arise as the result of a believing-brain with a proclivity towards pattern perception, but also as a compensatory strategy that seeks to endorse patterns (illusory or not) in order to alleviate aversive states, such as feeling a lack of control in an unpredictable environment.
Does well-designed, well-documented, psychologically principled, and carefully implemented psychotherapy lead to better outcomes than therapy of lower quality?
Jones, Payton J., Patrick Mair, Sofie Kuppens, and John R. Weisz. 2019. “An Upper Limit to Youth Psychotherapy Benefit? A Meta-analytic Copula Approach to Psychotherapy Outcomes.” OSF Preprints. March 28. doi:10.31219/osf.io/jsmf5
Abstract: Across 50 years of research, extensive efforts have been made to improve the effectiveness of psychotherapies for children and adolescents. Yet recent evidence shows no significant improvement in youth psychotherapy outcomes. In other words, efforts to improve the general quality of therapy models do not appear to have translated directly into improved outcomes. We used multilevel meta-analytic data from 502 randomized controlled trials to generate a bivariate copula model predicting effect size as therapy quality approaches infinity. Our results suggest that even with a therapy of perfect quality, achieved effect sizes may be modest. If therapy quality and therapy outcome share a correlation of 0.20 (a somewhat optimistic assumption given the evidence we review), a therapy of perfect quality would produce an effect size of Hedge's g = 0.83. We suggest that youth psychotherapy researchers complement their efforts to improve psychotherapy quality by investigating additional strategies for improving outcomes.
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Does well-designed, well-documented, psychologically principled, and carefully implemented psychotherapy lead to better outcomes than therapy of lower quality? Empirical evidence on the association between therapy "quality" and therapy outcome is more mixed than one might expect.
The literature reveals varying opinions on what constitutes a therapy of high quality. One view suggests that an important dimension of therapy quality is the presence of advantageous "specific factors" or "theory-specified factors" in psychotherapies (Castonguay & Grosse, 2005; Webb, DeRubeis, & Barber, 2010). These researchers emphasize the idea that the content of therapy is an important dimension of therapy quality. They stress the frequency with which certain theoretically-driven approaches involving specific content, such as exposure and response prevention for OCD, outperform other psychotherapies (DeRubeis, Brotman, & Gibbons, 2005). The "theory-specified factors"
perspective implies that randomized-controlled trials comparing different types of therapy are of great importance to the scientific literature, as this approach is likely to reveal the types of therapeutic content that are most effective in reducing psychopathology.
While differing specific factors and treatment types have often dominated the discussion of therapy, some influential theorists and researchers have discounted the importance of these factors.
Since 1936, some influential figures in the field have argued that the specific steps followed in therapy may have little impact, relative to the influence of certain common factors (Messer & Wampold, 2002; Rosenzweig, 1936). One prominent version of this perspective has been labeled the "Dodo Bird" conjecture, in reference to the character in Lewis Carol's book Alice in Wonderland, who proclaims: "Everybody has won, and all must have prizes." The Dodo Bird conjecture proposes that diverse types of therapies are equally effective, provided that they possess certain common factors. One aspect of this perspective is the notion that, across a broad range of “bona fide” therapies, the specific factors associated with therapy quality bear little relation to therapy outcome (Wampold et. al, 1997).
Importantly, the common factors approach does not discount the notion that therapy quality matters – it simply emphasizes different types of therapy quality which are independent of therapeutic content, such as adequate therapist training in facilitative interpersonal skills (Anderson, McClintock, Himawan, Song, & Patterson, 2016).
The Dodo Bird hypothesis has generated both controversy and data synthesis, with various meta analyses and reviews cited in support of each position in the debate. Some meta-analyses have failed to identify therapy type as a significant moderator of outcome (e.g., Baardseth et al., 2013; Miller, Wampold, & Verhely, 2008; Wampold et al., 1997), and these have been cited as support for the Dodo
Bird conjecture. Findings of other meta-analyses and some reviews have indicated that the specific procedures performed in therapy matter. For instance, some of these have identified significant between therapy type differences in magnitude of effect size for various treated problems (e.g., Chambless & Ollendick, 2001; Hunsley & DeGuilio, 2002; Weiss & Weisz, 1995; Weisz, Weiss, Han, Granger, &
Morton,1995), and others have identified therapies for which evidence shows adverse effects (Lilienfeld, 2007). The existence of harmful therapies suggests that the dimension of therapy quality is related to therapy outcome, at least on the extreme low end of therapy quality (e.g., where therapy is designed in
opposition to psychological principles). In other relevant work, researchers have shown that type of therapy can have a marked impact when symptoms are especially severe (e.g., Lorenzo-Luaces, DeRubeis, van Straten, & Tiemens, 2017). As these examples indicate, the various syntheses of evidence have suggested that therapy content may matter in some cases but not in all. Both theoretical camps promote the idea that psychotherapy varies in its quality and its quality can be improved, but the camps differ as to how this should be done. Researchers in the specific factors camp have focused on improving therapy content, whereas those in the common factors camp have focused on maximizing factors that exist independent of therapy content, such as therapist skills in interacting with clients.
Both perspectives are relevant to the present paper, in which we focus on the relation between psychotherapy quality and psychotherapy outcome. To define psychotherapy quality in a way that encompasses both perspectives, we have tried to synthesize points from both sides of the debate. The specific factors view suggests that high-quality in therapy will include the use of procedures that have a basis in sound psychological principles and the accumulation of evidence from empirical studies, together with training of therapists in the specific procedures involved, and insuring adherence to the specified protocols (e.g., Chambless & Ollendick, 2001). The common factors view suggests that high quality in therapy will include an array of therapist characteristics, such as skill in the interpersonal
aspects of working with clients. For purposes of the present paper, we include both perspectives, operationally defining "quality of therapy" to include both (1) the specific contents of therapy protocols and the procedures (e.g., therapist training) used to ensure faithful delivery of those contents, and (2) common factors (e.g., therapist interpersonal skills) that may influence the conduct of therapy independently of specific treatment content, provided that the procedures or elements of 1 and 2 are intended to improve client outcome and do not depend upon client factors.
To better understand how quality is defined and operationalized throughout this paper, one can use the metaphor of a psychological scale that measures therapy quality. Our metaphorical scale for quality would include a list of items that derive from both the specific factors and the common factors approach. When we refer to quality as a general principle, we refer to the metaphorical sum-score of all
items on the scale (or perhaps more precisely as an extracted principal component from all items). That is, we aim to represent quality as an abstract dimension comprising all relevant aspects of high-quality therapies.
How much does quality matter?
As noted, researchers have argued over what constitutes a high-quality therapy. But to what degree do these different aspects of therapy quality predict outcome? We reviewed the literature on psychotherapy quality in an exploratory search. Our aim was to identify empirical articles which estimated the relationship between therapy outcome and some aspect of psychotherapy quality. Because research in this area is scarce, we broadened our review of this area to include both adult and youth
focused therapies.
To make sure we had adequately represented diverse views on this issue, we contacted prominent psychotherapy researchers and asked them to recommend studies. To identify researchers, we searched PSYCinfo for the period from January 1990 to January 2018 using the terms "common factors in psychotherapy," "empirically supported psychotherapy," and "psychotherapy quality." We identified
authors of the identified publications who were frequently cited for work related to these topics. In addition, we identified current and past editors of journals in which psychotherapy research is frequently published. The resulting list of authors included 19 prominent researchers with diverse theoretical perspectives: David Barlow, Larry Beutler, Ronald Brown, Dianne Chambless, David Clark, Michelle
Craske, Joanne Davila, Robert DeRubeis, Judy Garber, Mark Hilsenroth, Steven Hollon, Alan Kazdin, Philip Kendall, Michael Lambert, John Norcross, Francheska Pereplechikova, Dan Strunk, and Bruce Wampold. We sent an email 1 to each author requesting that they identify as the most scientifically sound study in which the relationship between quality and outcome was assessed.
1 "Dear Professor ________:
As part of a new study examining the relation between psychotherapy quality and psychotherapy outcome, we are contacting you and a small number of other prominent psychotherapy researchers. We ask you to please identify what you regard as the most scientifically sound study in the literature in which investigators assessed the relation between a credible measure of psychotherapy quality, on the one hand, and therapy outcome, on the other hand.
If you can provide either a PDF or an exact reference for the study you identify, we will be very grateful. Thanks very much for considering our request."
Twelve of the nineteen authors responded to our request. Some of the authors declined to provide a study, noting theoretical concerns with the idea of therapy quality, or concerns related to unfamiliarity with more recent literature on therapy outcomes. Other authors provided more than one study. All studies provided, including results from our own initial literature review, were initially considered as part of the exploratory analysis.
After reviewing the full pool of nominated studies, we excluded several studies from further analyses due to 1) failure to report effect sizes 2) failure to include a discernable measure of therapy quality or 3) use of therapy quality measures that depended, in full or in part, upon client factors (e.g., therapeutic alliance between therapist and client). A list of excluded studies and reasons for exclusion can be found in the supplemental materials.
The results of our exploratory search are presented in Table 1. We measured a variety of different types of therapy quality, ranging from treatment type to therapist competence to therapist facilitative interpersonal skills. Our review included both single studies of therapy quality as well as meta-analyses of evidence across many studies. Aside from comparing different types of psychotherapy, none of the studies in our search included experimental manipulations of therapy quality, indicating an important area of research that may be neglected.
A histogram of the pooled effect sizes is presented in Figure 1. A high bar in this histogram indicates that many effect sizes in the literature fell within the range of effect indicated on the x-axis.
For instance, the first bar in the graph indicates that 17 effect sizes included in our review fell in the range between 0.00 and 0.02. Effect sizes are given as r2 type, which reflects the proportion of variance accounted for by therapy quality on therapy outcome (see Fritz, Morris, & Richler, 2012). In summary, most effect sizes were close to zero, indicating that higher therapy quality did not relate to better therapy
outcome. Meta-analyses and more recent studies in general reported smaller effects compared to individual studies and older studies. All meta-analytic effects fell between 0 and 0.005. In general, these exploratory analyses showed an association between therapy quality and therapy outcome that was quite modest, at best.
How good can therapy be? A focus on youth psychotherapy
After synthesizing findings of the studies listed in Table 1, we were interested in applying what could be learned from that synthesis to estimate the extent to which improving therapy quality might improve psychotherapy outcome. For that purpose, we needed a large pool of psychotherapy outcome studies. Because therapy procedures and protocols, as well as required therapist skills, are quite different
for treatment of children and adolescents (herein “youths”) than adults, we thought it best to focus on one or the other age group. While both age groups are important, our past research on youth psychopathology and psychotherapy, plus the fact that we had access to data from 502 randomized controlled trials of youth psychotherapy, led to our focus on therapy with young people. This work
illustrates a procedure that could, of course, be applied in the future to any group, defined by age or any other factor. Using this large youth psychotherapy dataset, we sought to determine the efficacy of an "optimal quality" therapy – that is, a therapy in which all beneficial clinician factors were maximized. In other words, we were not interested in answering the question of "how good is therapy", but rather in answering the question of "how good could therapy be?" Answering this question is akin to an optimization problem in mathematics. First, a function must be specified which describes relevant inputs (therapy quality) and outputs (therapy outcome). The function is then analyzed to identify the point at which a maximal output is achieved based on the inputs. We sought to answer this question based on relevant knowledge regarding youth psychotherapy quality and outcome.
To address these questions using empirical data, we first generated a bivariate distribution function, known as a copula, between therapy quality and treatment outcome drawing upon an extensive meta-analysis of randomized controlled trials (RCTs) of youth psychotherapy. We then utilized our simulated distribution to predict the upper limit of effect size as therapy quality approaches infinity. In other words, we posed the question: if we could design a youth psychotherapy of perfect quality, how effective would it be?
Abstract: Across 50 years of research, extensive efforts have been made to improve the effectiveness of psychotherapies for children and adolescents. Yet recent evidence shows no significant improvement in youth psychotherapy outcomes. In other words, efforts to improve the general quality of therapy models do not appear to have translated directly into improved outcomes. We used multilevel meta-analytic data from 502 randomized controlled trials to generate a bivariate copula model predicting effect size as therapy quality approaches infinity. Our results suggest that even with a therapy of perfect quality, achieved effect sizes may be modest. If therapy quality and therapy outcome share a correlation of 0.20 (a somewhat optimistic assumption given the evidence we review), a therapy of perfect quality would produce an effect size of Hedge's g = 0.83. We suggest that youth psychotherapy researchers complement their efforts to improve psychotherapy quality by investigating additional strategies for improving outcomes.
---
Does well-designed, well-documented, psychologically principled, and carefully implemented psychotherapy lead to better outcomes than therapy of lower quality? Empirical evidence on the association between therapy "quality" and therapy outcome is more mixed than one might expect.
The literature reveals varying opinions on what constitutes a therapy of high quality. One view suggests that an important dimension of therapy quality is the presence of advantageous "specific factors" or "theory-specified factors" in psychotherapies (Castonguay & Grosse, 2005; Webb, DeRubeis, & Barber, 2010). These researchers emphasize the idea that the content of therapy is an important dimension of therapy quality. They stress the frequency with which certain theoretically-driven approaches involving specific content, such as exposure and response prevention for OCD, outperform other psychotherapies (DeRubeis, Brotman, & Gibbons, 2005). The "theory-specified factors"
perspective implies that randomized-controlled trials comparing different types of therapy are of great importance to the scientific literature, as this approach is likely to reveal the types of therapeutic content that are most effective in reducing psychopathology.
While differing specific factors and treatment types have often dominated the discussion of therapy, some influential theorists and researchers have discounted the importance of these factors.
Since 1936, some influential figures in the field have argued that the specific steps followed in therapy may have little impact, relative to the influence of certain common factors (Messer & Wampold, 2002; Rosenzweig, 1936). One prominent version of this perspective has been labeled the "Dodo Bird" conjecture, in reference to the character in Lewis Carol's book Alice in Wonderland, who proclaims: "Everybody has won, and all must have prizes." The Dodo Bird conjecture proposes that diverse types of therapies are equally effective, provided that they possess certain common factors. One aspect of this perspective is the notion that, across a broad range of “bona fide” therapies, the specific factors associated with therapy quality bear little relation to therapy outcome (Wampold et. al, 1997).
Importantly, the common factors approach does not discount the notion that therapy quality matters – it simply emphasizes different types of therapy quality which are independent of therapeutic content, such as adequate therapist training in facilitative interpersonal skills (Anderson, McClintock, Himawan, Song, & Patterson, 2016).
The Dodo Bird hypothesis has generated both controversy and data synthesis, with various meta analyses and reviews cited in support of each position in the debate. Some meta-analyses have failed to identify therapy type as a significant moderator of outcome (e.g., Baardseth et al., 2013; Miller, Wampold, & Verhely, 2008; Wampold et al., 1997), and these have been cited as support for the Dodo
Bird conjecture. Findings of other meta-analyses and some reviews have indicated that the specific procedures performed in therapy matter. For instance, some of these have identified significant between therapy type differences in magnitude of effect size for various treated problems (e.g., Chambless & Ollendick, 2001; Hunsley & DeGuilio, 2002; Weiss & Weisz, 1995; Weisz, Weiss, Han, Granger, &
Morton,1995), and others have identified therapies for which evidence shows adverse effects (Lilienfeld, 2007). The existence of harmful therapies suggests that the dimension of therapy quality is related to therapy outcome, at least on the extreme low end of therapy quality (e.g., where therapy is designed in
opposition to psychological principles). In other relevant work, researchers have shown that type of therapy can have a marked impact when symptoms are especially severe (e.g., Lorenzo-Luaces, DeRubeis, van Straten, & Tiemens, 2017). As these examples indicate, the various syntheses of evidence have suggested that therapy content may matter in some cases but not in all. Both theoretical camps promote the idea that psychotherapy varies in its quality and its quality can be improved, but the camps differ as to how this should be done. Researchers in the specific factors camp have focused on improving therapy content, whereas those in the common factors camp have focused on maximizing factors that exist independent of therapy content, such as therapist skills in interacting with clients.
Both perspectives are relevant to the present paper, in which we focus on the relation between psychotherapy quality and psychotherapy outcome. To define psychotherapy quality in a way that encompasses both perspectives, we have tried to synthesize points from both sides of the debate. The specific factors view suggests that high-quality in therapy will include the use of procedures that have a basis in sound psychological principles and the accumulation of evidence from empirical studies, together with training of therapists in the specific procedures involved, and insuring adherence to the specified protocols (e.g., Chambless & Ollendick, 2001). The common factors view suggests that high quality in therapy will include an array of therapist characteristics, such as skill in the interpersonal
aspects of working with clients. For purposes of the present paper, we include both perspectives, operationally defining "quality of therapy" to include both (1) the specific contents of therapy protocols and the procedures (e.g., therapist training) used to ensure faithful delivery of those contents, and (2) common factors (e.g., therapist interpersonal skills) that may influence the conduct of therapy independently of specific treatment content, provided that the procedures or elements of 1 and 2 are intended to improve client outcome and do not depend upon client factors.
To better understand how quality is defined and operationalized throughout this paper, one can use the metaphor of a psychological scale that measures therapy quality. Our metaphorical scale for quality would include a list of items that derive from both the specific factors and the common factors approach. When we refer to quality as a general principle, we refer to the metaphorical sum-score of all
items on the scale (or perhaps more precisely as an extracted principal component from all items). That is, we aim to represent quality as an abstract dimension comprising all relevant aspects of high-quality therapies.
How much does quality matter?
As noted, researchers have argued over what constitutes a high-quality therapy. But to what degree do these different aspects of therapy quality predict outcome? We reviewed the literature on psychotherapy quality in an exploratory search. Our aim was to identify empirical articles which estimated the relationship between therapy outcome and some aspect of psychotherapy quality. Because research in this area is scarce, we broadened our review of this area to include both adult and youth
focused therapies.
To make sure we had adequately represented diverse views on this issue, we contacted prominent psychotherapy researchers and asked them to recommend studies. To identify researchers, we searched PSYCinfo for the period from January 1990 to January 2018 using the terms "common factors in psychotherapy," "empirically supported psychotherapy," and "psychotherapy quality." We identified
authors of the identified publications who were frequently cited for work related to these topics. In addition, we identified current and past editors of journals in which psychotherapy research is frequently published. The resulting list of authors included 19 prominent researchers with diverse theoretical perspectives: David Barlow, Larry Beutler, Ronald Brown, Dianne Chambless, David Clark, Michelle
Craske, Joanne Davila, Robert DeRubeis, Judy Garber, Mark Hilsenroth, Steven Hollon, Alan Kazdin, Philip Kendall, Michael Lambert, John Norcross, Francheska Pereplechikova, Dan Strunk, and Bruce Wampold. We sent an email 1 to each author requesting that they identify as the most scientifically sound study in which the relationship between quality and outcome was assessed.
1 "Dear Professor ________:
As part of a new study examining the relation between psychotherapy quality and psychotherapy outcome, we are contacting you and a small number of other prominent psychotherapy researchers. We ask you to please identify what you regard as the most scientifically sound study in the literature in which investigators assessed the relation between a credible measure of psychotherapy quality, on the one hand, and therapy outcome, on the other hand.
If you can provide either a PDF or an exact reference for the study you identify, we will be very grateful. Thanks very much for considering our request."
Twelve of the nineteen authors responded to our request. Some of the authors declined to provide a study, noting theoretical concerns with the idea of therapy quality, or concerns related to unfamiliarity with more recent literature on therapy outcomes. Other authors provided more than one study. All studies provided, including results from our own initial literature review, were initially considered as part of the exploratory analysis.
After reviewing the full pool of nominated studies, we excluded several studies from further analyses due to 1) failure to report effect sizes 2) failure to include a discernable measure of therapy quality or 3) use of therapy quality measures that depended, in full or in part, upon client factors (e.g., therapeutic alliance between therapist and client). A list of excluded studies and reasons for exclusion can be found in the supplemental materials.
The results of our exploratory search are presented in Table 1. We measured a variety of different types of therapy quality, ranging from treatment type to therapist competence to therapist facilitative interpersonal skills. Our review included both single studies of therapy quality as well as meta-analyses of evidence across many studies. Aside from comparing different types of psychotherapy, none of the studies in our search included experimental manipulations of therapy quality, indicating an important area of research that may be neglected.
A histogram of the pooled effect sizes is presented in Figure 1. A high bar in this histogram indicates that many effect sizes in the literature fell within the range of effect indicated on the x-axis.
For instance, the first bar in the graph indicates that 17 effect sizes included in our review fell in the range between 0.00 and 0.02. Effect sizes are given as r2 type, which reflects the proportion of variance accounted for by therapy quality on therapy outcome (see Fritz, Morris, & Richler, 2012). In summary, most effect sizes were close to zero, indicating that higher therapy quality did not relate to better therapy
outcome. Meta-analyses and more recent studies in general reported smaller effects compared to individual studies and older studies. All meta-analytic effects fell between 0 and 0.005. In general, these exploratory analyses showed an association between therapy quality and therapy outcome that was quite modest, at best.
How good can therapy be? A focus on youth psychotherapy
After synthesizing findings of the studies listed in Table 1, we were interested in applying what could be learned from that synthesis to estimate the extent to which improving therapy quality might improve psychotherapy outcome. For that purpose, we needed a large pool of psychotherapy outcome studies. Because therapy procedures and protocols, as well as required therapist skills, are quite different
for treatment of children and adolescents (herein “youths”) than adults, we thought it best to focus on one or the other age group. While both age groups are important, our past research on youth psychopathology and psychotherapy, plus the fact that we had access to data from 502 randomized controlled trials of youth psychotherapy, led to our focus on therapy with young people. This work
illustrates a procedure that could, of course, be applied in the future to any group, defined by age or any other factor. Using this large youth psychotherapy dataset, we sought to determine the efficacy of an "optimal quality" therapy – that is, a therapy in which all beneficial clinician factors were maximized. In other words, we were not interested in answering the question of "how good is therapy", but rather in answering the question of "how good could therapy be?" Answering this question is akin to an optimization problem in mathematics. First, a function must be specified which describes relevant inputs (therapy quality) and outputs (therapy outcome). The function is then analyzed to identify the point at which a maximal output is achieved based on the inputs. We sought to answer this question based on relevant knowledge regarding youth psychotherapy quality and outcome.
To address these questions using empirical data, we first generated a bivariate distribution function, known as a copula, between therapy quality and treatment outcome drawing upon an extensive meta-analysis of randomized controlled trials (RCTs) of youth psychotherapy. We then utilized our simulated distribution to predict the upper limit of effect size as therapy quality approaches infinity. In other words, we posed the question: if we could design a youth psychotherapy of perfect quality, how effective would it be?
Paracetamol reduces affective reactivity to other people’s positive experiences; & the experience of physical pain & positive empathy may have a more similar neurochemical basis than previously assumed
A Social Analgesic? Acetaminophen (Paracetamol) Reduces Positive Empathy
Dominik Mischkowski, Jennifer Crocker and Baldwin M. Way. Front. Psychol., March 29 2019. https://doi.org/10.3389/fpsyg.2019.00538
Abstract: Acetaminophen – a potent physical painkiller that also reduces empathy for other people’s suffering – blunts physical and social pain by reducing activation in brain areas (i.e. anterior insula and anterior cingulate) thought to be related to emotional awareness and motivation. Some neuroimaging research on positive empathy (i.e., the perception and sharing of positive affect in other people) suggests that the experience of positive empathy also recruits these paralimbic cortical brain areas. We thus hypothesized that acetaminophen may also impair affective processes related to the experience of positive empathy. We tested this hypothesis in a double-blind, placebo-controlled experiment. Specifically, we administered 1,000 mg acetaminophen or a placebo and measured effects on different measures of positive empathy while participants read scenarios about the uplifting experiences of other people. Results showed that acetaminophen reduced personal pleasure and other-directed empathic feelings in response to these scenarios. In contrast, effects on perceived positivity of the described experiences or perceived pleasure in scenario protagonists were not significant. These findings suggest that (1) acetaminophen reduces affective reactivity to other people’s positive experiences and (2) the experience of physical pain and positive empathy may have a more similar neurochemical basis than previously assumed. Because the experience of positive empathy is related to prosocial behavior, our findings also raise questions about the societal impact of excessive acetaminophen consumption.
---
Experiencing and expressing positive empathy for other people’s good fortunes have striking personal and interpersonal benefits (Morelli et al., 2015). A substantial amount of research shows that understanding and sharing in other people’s pleasurable experiences foster psychological health, interpersonal trust, intimacy, and a prosocial orientation, both for the source and the recipient of positive empathy (Smith et al., 1989; Gable et al., 2006; Sallquist et al., 2009; Reis et al., 2010; Morelli et al., 2015; Andreychik and Lewis, 2017). Despite this host of findings on the psychological and relational benefits of positive empathy, however, our understanding of the physiological bases of positive empathy remains limited.
Most recent research on the biological underpinnings of positive empathy has focused on pinpointing its brain correlates using functional magnetic resonance imaging (fMRI; e.g., Immordino-Yang et al., 2009; Mobbs et al., 2009; Morelli et al., 2014; Lamm et al., 2015; Lockwood, 2016; Chiesa et al., 2017). Across fMRI studies, the experience of positive empathy seems to be represented in a complex neuronal network involved in emotional awareness, shared affect, and vicarious reward (e.g., Immordino-Yang et al., 2009; Ebisch et al., 2011; Braams et al., 2013; Apps and Ramnani, 2014; Lamm et al., 2015; Morelli et al., 2015). These studies have shown that positive empathy has a distinct neuronal signature compared to related psychosocial affective experiences, such as personal reward or negative empathy, which is generally defined as responsiveness to other people’s pain (Immordino-Yang et al., 2009; Ebisch et al., 2011; Morelli et al., 2014, 2015; Lamm et al., 2015; Lockwood, 2016). fMRI can contribute to our understanding of the component psychological processes of positive empathy but constitutes a correlational methodology, which limits our ability to make causal conclusions about the different processes underlying empathy (Decety, 2010; Zaki et al., 2016; Lamm et al., 2017).
Pharmacological experiments can supplement existing correlational findings about the nature of empathy, because such studies add a causal approach to the study of empathy’s psychological underpinnings (e.g., Rütgen et al., 2015, 2017; Mischkowski et al., 2016). Recent research suggests that the painkiller acetaminophen (or paracetamol, under its international designation) may be particularly well suited for studying the psychology of empathy, as acetaminophen reduces empathy for pain (Mischkowski et al., 2016). Acetaminophen is one of the most popular medicines in the USA (Kaufman et al., 2002) and easily accessible over the counter. Furthermore, acetaminophen is a potent analgesic, reducing pain in response to heat, electric shock, or cold (e.g., Bromm et al., 1992; Nielsen et al., 1992; Piguet et al., 1998; Yuan et al., 1998; Pickering et al., 2015). In addition to these effects on pain, acetaminophen also reduces psychological reactivity (e.g., DeWall et al., 2010; Randles et al., 2013, 2016; Durso et al., 2015; Roberts et al., 2017). Thus, acetaminophen affects a broad spectrum of psychological processes that are not limited to the processing of physical pain.
Neuroimaging evidence suggests that key brain areas involved in these psychological effects of acetaminophen are likely to be the anterior insula (AI) and anterior parts of the cingulate cortex (dACC). Acetaminophen reduces activation in these areas during physical and emotional pain (DeWall et al., 2010; Pickering et al., 2015). Some researchers have pointed out the centrality of these brain areas for positive empathy, as well (e.g., Immordino-Yang et al., 2009; Apps and Ramnani, 2014; Lockwood, 2016). This shared neural mechanism is plausible as the AI seems to be the core of a limbic cortical network related to emotional awareness, independent of emotional valence (Craig, 2009). Thus, both positive and negative empathy may rely on AI and ACC, even though these types of empathy are differentiable at other levels along the neuroaxis. Because acetaminophen appears to blunt responsiveness for one’s own pain and for the pain of others in brain areas overlapping with those involved in positive empathy, we hypothesize that acetaminophen may also impair people’s ability to experience empathy for others’ positive experiences.
To test this hypothesis, we used unpublished data from a previously published dataset (Study 2; Mischkowski et al., 2016). We administered acetaminophen or an inert placebo to healthy volunteers and tested participants’ empathic responses when reading written scenarios about different protagonists having uplifting, positive experiences. To further probe the effect of acetaminophen on positive empathy, we distinguished between empathic perceptions and empathic affect when measuring positive empathy (e.g., Davis, 1994; Decety and Jackson, 2004; Coll et al., 2017; de Waal and Preston, 2017); two of the core psychological processes of positive empathy are perspective taking and affect sharing – conceptual features of both positive empathy and empathy for pain (Morelli et al., 2015). To measure empathic perceptions, participants rated the perceived positivity of the uplifting experiences in the scenarios and the perceived pleasure in the scenario protagonists. To measure empathic affect, we focused on participants’ ability to affectively share in other people’s positive experiences. Specifically, participants rated personal pleasure for themselves and positive other-directed empathic feelings in response to scenario protagonists’ positive experiences. Finally, we explored a process model in which reductions in empathic perceptions statistically mediated the effects of acetaminophen consumption on reduced empathic affect to test whether the effects of acetaminophen on empathic affect are driven by respective impairments in empathic cognition, or not.
Dominik Mischkowski, Jennifer Crocker and Baldwin M. Way. Front. Psychol., March 29 2019. https://doi.org/10.3389/fpsyg.2019.00538
Abstract: Acetaminophen – a potent physical painkiller that also reduces empathy for other people’s suffering – blunts physical and social pain by reducing activation in brain areas (i.e. anterior insula and anterior cingulate) thought to be related to emotional awareness and motivation. Some neuroimaging research on positive empathy (i.e., the perception and sharing of positive affect in other people) suggests that the experience of positive empathy also recruits these paralimbic cortical brain areas. We thus hypothesized that acetaminophen may also impair affective processes related to the experience of positive empathy. We tested this hypothesis in a double-blind, placebo-controlled experiment. Specifically, we administered 1,000 mg acetaminophen or a placebo and measured effects on different measures of positive empathy while participants read scenarios about the uplifting experiences of other people. Results showed that acetaminophen reduced personal pleasure and other-directed empathic feelings in response to these scenarios. In contrast, effects on perceived positivity of the described experiences or perceived pleasure in scenario protagonists were not significant. These findings suggest that (1) acetaminophen reduces affective reactivity to other people’s positive experiences and (2) the experience of physical pain and positive empathy may have a more similar neurochemical basis than previously assumed. Because the experience of positive empathy is related to prosocial behavior, our findings also raise questions about the societal impact of excessive acetaminophen consumption.
---
Experiencing and expressing positive empathy for other people’s good fortunes have striking personal and interpersonal benefits (Morelli et al., 2015). A substantial amount of research shows that understanding and sharing in other people’s pleasurable experiences foster psychological health, interpersonal trust, intimacy, and a prosocial orientation, both for the source and the recipient of positive empathy (Smith et al., 1989; Gable et al., 2006; Sallquist et al., 2009; Reis et al., 2010; Morelli et al., 2015; Andreychik and Lewis, 2017). Despite this host of findings on the psychological and relational benefits of positive empathy, however, our understanding of the physiological bases of positive empathy remains limited.
Most recent research on the biological underpinnings of positive empathy has focused on pinpointing its brain correlates using functional magnetic resonance imaging (fMRI; e.g., Immordino-Yang et al., 2009; Mobbs et al., 2009; Morelli et al., 2014; Lamm et al., 2015; Lockwood, 2016; Chiesa et al., 2017). Across fMRI studies, the experience of positive empathy seems to be represented in a complex neuronal network involved in emotional awareness, shared affect, and vicarious reward (e.g., Immordino-Yang et al., 2009; Ebisch et al., 2011; Braams et al., 2013; Apps and Ramnani, 2014; Lamm et al., 2015; Morelli et al., 2015). These studies have shown that positive empathy has a distinct neuronal signature compared to related psychosocial affective experiences, such as personal reward or negative empathy, which is generally defined as responsiveness to other people’s pain (Immordino-Yang et al., 2009; Ebisch et al., 2011; Morelli et al., 2014, 2015; Lamm et al., 2015; Lockwood, 2016). fMRI can contribute to our understanding of the component psychological processes of positive empathy but constitutes a correlational methodology, which limits our ability to make causal conclusions about the different processes underlying empathy (Decety, 2010; Zaki et al., 2016; Lamm et al., 2017).
Pharmacological experiments can supplement existing correlational findings about the nature of empathy, because such studies add a causal approach to the study of empathy’s psychological underpinnings (e.g., Rütgen et al., 2015, 2017; Mischkowski et al., 2016). Recent research suggests that the painkiller acetaminophen (or paracetamol, under its international designation) may be particularly well suited for studying the psychology of empathy, as acetaminophen reduces empathy for pain (Mischkowski et al., 2016). Acetaminophen is one of the most popular medicines in the USA (Kaufman et al., 2002) and easily accessible over the counter. Furthermore, acetaminophen is a potent analgesic, reducing pain in response to heat, electric shock, or cold (e.g., Bromm et al., 1992; Nielsen et al., 1992; Piguet et al., 1998; Yuan et al., 1998; Pickering et al., 2015). In addition to these effects on pain, acetaminophen also reduces psychological reactivity (e.g., DeWall et al., 2010; Randles et al., 2013, 2016; Durso et al., 2015; Roberts et al., 2017). Thus, acetaminophen affects a broad spectrum of psychological processes that are not limited to the processing of physical pain.
Neuroimaging evidence suggests that key brain areas involved in these psychological effects of acetaminophen are likely to be the anterior insula (AI) and anterior parts of the cingulate cortex (dACC). Acetaminophen reduces activation in these areas during physical and emotional pain (DeWall et al., 2010; Pickering et al., 2015). Some researchers have pointed out the centrality of these brain areas for positive empathy, as well (e.g., Immordino-Yang et al., 2009; Apps and Ramnani, 2014; Lockwood, 2016). This shared neural mechanism is plausible as the AI seems to be the core of a limbic cortical network related to emotional awareness, independent of emotional valence (Craig, 2009). Thus, both positive and negative empathy may rely on AI and ACC, even though these types of empathy are differentiable at other levels along the neuroaxis. Because acetaminophen appears to blunt responsiveness for one’s own pain and for the pain of others in brain areas overlapping with those involved in positive empathy, we hypothesize that acetaminophen may also impair people’s ability to experience empathy for others’ positive experiences.
To test this hypothesis, we used unpublished data from a previously published dataset (Study 2; Mischkowski et al., 2016). We administered acetaminophen or an inert placebo to healthy volunteers and tested participants’ empathic responses when reading written scenarios about different protagonists having uplifting, positive experiences. To further probe the effect of acetaminophen on positive empathy, we distinguished between empathic perceptions and empathic affect when measuring positive empathy (e.g., Davis, 1994; Decety and Jackson, 2004; Coll et al., 2017; de Waal and Preston, 2017); two of the core psychological processes of positive empathy are perspective taking and affect sharing – conceptual features of both positive empathy and empathy for pain (Morelli et al., 2015). To measure empathic perceptions, participants rated the perceived positivity of the uplifting experiences in the scenarios and the perceived pleasure in the scenario protagonists. To measure empathic affect, we focused on participants’ ability to affectively share in other people’s positive experiences. Specifically, participants rated personal pleasure for themselves and positive other-directed empathic feelings in response to scenario protagonists’ positive experiences. Finally, we explored a process model in which reductions in empathic perceptions statistically mediated the effects of acetaminophen consumption on reduced empathic affect to test whether the effects of acetaminophen on empathic affect are driven by respective impairments in empathic cognition, or not.
Thursday, March 28, 2019
A Model for Public Access to Trustworthy and Comprehensive Reporting of Research
A Model for Public Access to Trustworthy and Comprehensive Reporting of Research. Marina Broitman, Harold C. Sox, Jean Slutsky. JAMA, March 28, 2019. doi:10.1001/jama.2019.2807
The Patient-Centered Outcomes Research Institute (PCORI) was authorized by Congress in 2010 to fund comparative clinical effectiveness research. The legislation required the institute to guarantee peer review of all research results and to make those results publicly accessible within 90 days of their receipt, requirements that were the first of their kind for a US-based research funding organization. The authorizing legislation further stipulated that the peer review should assess the scientific integrity of each study and its adherence to the methodological standards established by the PCORI methodology committee.1 The law broadly defined the forms of peer review that would be acceptable.
The PCORI board of governors, after comment from patients, clinicians, professional interest groups, and journal editors, established a peer review process2 requiring all awardees to submit a comprehensive final report for PCORI-based external peer review. After final approval, the institute would post on its website lay and technical abstracts of the report; the complete, approved final report and study protocol; and a summary of the peer review critiques and the authors’ responses to those critiques. This Viewpoint describes the peer review system and the comprehensive report, which are the essential elements of this program, and discusses the problems each raise and the potential benefits.
The PCORI peer review process is similar to the review process at some journals in its use of methods experts and clinician-scientists as external reviewers. However, PCORI peer review is unique in its recruiting of patients, caregivers, health care professionals, and policy makers to critique the relevance and usefulness of the research. The institute engaged a contractor to manage the external peer review process to help ensure its impartiality. Each report receives 4 to 5 external reviews and a comprehensive review from the peer review editor.
The final research report is structured like a journal article, but is 3 to 4 times longer to accommodate a complete account of all study aims, methods, and results. The report also includes an account of the study’s adherence to the PCORI methodology standards1 and a section for patient engagement in research, in which the authors describe their partnership and collaborations with interested groups and individuals (including patients and other health care decision makers) in the development, implementation, and interpretation of the study. Per legislative requirements, the report must describe the study limitations and how the comparative effectiveness of the study interventions differs among various subgroups of study participants.
From October 6, 2016, to February 28, 2019, there were 275 final reports submitted for peer review and 206 had completed all revisions following peer review. As of February 28, 2019, PCORI has posted 177 publicly available lay and technical abstracts based on those reports as well as 41 of the full reports. Posting the study results could jeopardize journal publication; therefore, the institute waits 12 months after completion of peer review to post the final research report on its website unless the main study results have already been published in a journal article.
The institute met its legislative mandates. It established a peer review process and the requirement to write a comprehensive report, and it publishes lay and technical abstracts of the final report within 90 days of completing peer review. The vision of the sponsors of the legislation (ie, prompt public access to all study results following peer review) is achievable but at what cost and with what benefits? It is possible now to describe some of the challenges and speculate about potential benefits.
To assess the effects of requiring a comprehensive report, the institute surveyed 191 investigators about their experiences with final research report preparation and peer review and 52% responded. Some awardees raised complaints about the burden of writing a comprehensive final report and responding to peer review when they are preparing manuscripts to submit to journals. Others reported that writing the final report helped them to identify topics, text, and tables for focused articles. Many did not see an added value from the comprehensive final report, which increased their frustration with the time and effort involved. Survey respondents estimated that their research teams spent between 160 to 255 hours preparing the final report and responding to reviewer critiques.
The peer review process is taking longer than originally expected. Instead of the 4 to 6 months estimated by the PCORI board of governors,2 peer review takes a median of 8 to 9 months from submission to final acceptance. Unlike journals that can quickly reject unsuitable articles, the institute must accept and publicly post all reports. Some reports require many rounds of review and revision, which delays completion of peer review and public release of the results.
These problems are present and real, whereas the most substantial benefits lie in the future. First, the public is likely to benefit from a full report of research even when the results are unlikely to change practice. Because inconclusive studies are the least likely to be published in a scientific journal,3 the published body of evidence is incomplete and is likely biased toward positive results,4 which is a problem for systematic reviewers, guideline developers, and many others who rely on evidence to make decisions, including clinicians and patients. Journal articles and research registries each play a key role in informing the public, but a comprehensive final research report can fill a gap in public reporting by providing an in-depth account of a study, including all results and lessons learned from doing the research, regardless of study success.
Second, study authors may benefit from the institute’s peer review of their final research report before they submit manuscripts to a journal. Researchers can use the critiques by the PCORI peer reviewers to anticipate the concerns of journal reviewers and shape journal manuscripts accordingly. When the final research report for the institute is prepared (after publication of a journal article), authors can include information that journals typically do not publish such as a narrative account of how the study unfolded (including explanations of key decisions) and a full account of the patients and others who partnered with the researchers to conduct the study.
Dual peer review and publication could cause problems, especially when the description of research in a journal article conflicts with the final report. These differences are best handled by transparent reporting of the reasons for the discrepancies. When report authors disagree with the recommendations from the peer reviewers, both sides of the disagreement are captured in the peer review summary.
Third, a comprehensive final report supports the goal of increasing the efficiency of research by providing essentially unlimited space in which to describe how a 3- to 5-year study developed and evolved and to transmit all results and lessons learned to other researchers and funding agencies.5 Posted final research reports that provide all study results, including unpublished secondary or inconclusive results, may provide leads for others to investigate, describe pitfalls to avoid, or describe a line of investigation that led nowhere and should be avoided.
Fourth, the funder that requires a final research report can learn from systematically examining the research that it has supported, especially if reports have been peer reviewed. Ongoing review of its body of funded research could inform many aspects of the work of a funding agency such as the choice of high-priority research topics for funding announcements, instructions to applicants, the evaluation of research proposals, postaward negotiations to strengthen the study, and monitoring research while it is in progress. Peer review of adherence to the PCORI methodology standards has identified several recurring methodological shortcomings that the institute must address.
In the future, these potential benefits of requiring a peer-reviewed, publicly available comprehensive final report will be weighed against the costs. In a few years, it will be possible to determine if these final reports have expanded the reach of each research study, whether they are used in systematic reviews, and how lessons learned from peer review of the final reports have changed the way that the institute does its work. For the present, it may be enough to hope that an openly accessible peer-reviewed comprehensive final research report will help to increase public trust in research. It is possible that the sponsors of the legislation were on to something important when they set the institute on this path. However, the realization of their vision is in its infancy and its putative benefits are largely speculative. There is still much to learn.
The Patient-Centered Outcomes Research Institute (PCORI) was authorized by Congress in 2010 to fund comparative clinical effectiveness research. The legislation required the institute to guarantee peer review of all research results and to make those results publicly accessible within 90 days of their receipt, requirements that were the first of their kind for a US-based research funding organization. The authorizing legislation further stipulated that the peer review should assess the scientific integrity of each study and its adherence to the methodological standards established by the PCORI methodology committee.1 The law broadly defined the forms of peer review that would be acceptable.
The PCORI board of governors, after comment from patients, clinicians, professional interest groups, and journal editors, established a peer review process2 requiring all awardees to submit a comprehensive final report for PCORI-based external peer review. After final approval, the institute would post on its website lay and technical abstracts of the report; the complete, approved final report and study protocol; and a summary of the peer review critiques and the authors’ responses to those critiques. This Viewpoint describes the peer review system and the comprehensive report, which are the essential elements of this program, and discusses the problems each raise and the potential benefits.
The PCORI peer review process is similar to the review process at some journals in its use of methods experts and clinician-scientists as external reviewers. However, PCORI peer review is unique in its recruiting of patients, caregivers, health care professionals, and policy makers to critique the relevance and usefulness of the research. The institute engaged a contractor to manage the external peer review process to help ensure its impartiality. Each report receives 4 to 5 external reviews and a comprehensive review from the peer review editor.
The final research report is structured like a journal article, but is 3 to 4 times longer to accommodate a complete account of all study aims, methods, and results. The report also includes an account of the study’s adherence to the PCORI methodology standards1 and a section for patient engagement in research, in which the authors describe their partnership and collaborations with interested groups and individuals (including patients and other health care decision makers) in the development, implementation, and interpretation of the study. Per legislative requirements, the report must describe the study limitations and how the comparative effectiveness of the study interventions differs among various subgroups of study participants.
From October 6, 2016, to February 28, 2019, there were 275 final reports submitted for peer review and 206 had completed all revisions following peer review. As of February 28, 2019, PCORI has posted 177 publicly available lay and technical abstracts based on those reports as well as 41 of the full reports. Posting the study results could jeopardize journal publication; therefore, the institute waits 12 months after completion of peer review to post the final research report on its website unless the main study results have already been published in a journal article.
The institute met its legislative mandates. It established a peer review process and the requirement to write a comprehensive report, and it publishes lay and technical abstracts of the final report within 90 days of completing peer review. The vision of the sponsors of the legislation (ie, prompt public access to all study results following peer review) is achievable but at what cost and with what benefits? It is possible now to describe some of the challenges and speculate about potential benefits.
To assess the effects of requiring a comprehensive report, the institute surveyed 191 investigators about their experiences with final research report preparation and peer review and 52% responded. Some awardees raised complaints about the burden of writing a comprehensive final report and responding to peer review when they are preparing manuscripts to submit to journals. Others reported that writing the final report helped them to identify topics, text, and tables for focused articles. Many did not see an added value from the comprehensive final report, which increased their frustration with the time and effort involved. Survey respondents estimated that their research teams spent between 160 to 255 hours preparing the final report and responding to reviewer critiques.
The peer review process is taking longer than originally expected. Instead of the 4 to 6 months estimated by the PCORI board of governors,2 peer review takes a median of 8 to 9 months from submission to final acceptance. Unlike journals that can quickly reject unsuitable articles, the institute must accept and publicly post all reports. Some reports require many rounds of review and revision, which delays completion of peer review and public release of the results.
These problems are present and real, whereas the most substantial benefits lie in the future. First, the public is likely to benefit from a full report of research even when the results are unlikely to change practice. Because inconclusive studies are the least likely to be published in a scientific journal,3 the published body of evidence is incomplete and is likely biased toward positive results,4 which is a problem for systematic reviewers, guideline developers, and many others who rely on evidence to make decisions, including clinicians and patients. Journal articles and research registries each play a key role in informing the public, but a comprehensive final research report can fill a gap in public reporting by providing an in-depth account of a study, including all results and lessons learned from doing the research, regardless of study success.
Second, study authors may benefit from the institute’s peer review of their final research report before they submit manuscripts to a journal. Researchers can use the critiques by the PCORI peer reviewers to anticipate the concerns of journal reviewers and shape journal manuscripts accordingly. When the final research report for the institute is prepared (after publication of a journal article), authors can include information that journals typically do not publish such as a narrative account of how the study unfolded (including explanations of key decisions) and a full account of the patients and others who partnered with the researchers to conduct the study.
Dual peer review and publication could cause problems, especially when the description of research in a journal article conflicts with the final report. These differences are best handled by transparent reporting of the reasons for the discrepancies. When report authors disagree with the recommendations from the peer reviewers, both sides of the disagreement are captured in the peer review summary.
Third, a comprehensive final report supports the goal of increasing the efficiency of research by providing essentially unlimited space in which to describe how a 3- to 5-year study developed and evolved and to transmit all results and lessons learned to other researchers and funding agencies.5 Posted final research reports that provide all study results, including unpublished secondary or inconclusive results, may provide leads for others to investigate, describe pitfalls to avoid, or describe a line of investigation that led nowhere and should be avoided.
Fourth, the funder that requires a final research report can learn from systematically examining the research that it has supported, especially if reports have been peer reviewed. Ongoing review of its body of funded research could inform many aspects of the work of a funding agency such as the choice of high-priority research topics for funding announcements, instructions to applicants, the evaluation of research proposals, postaward negotiations to strengthen the study, and monitoring research while it is in progress. Peer review of adherence to the PCORI methodology standards has identified several recurring methodological shortcomings that the institute must address.
In the future, these potential benefits of requiring a peer-reviewed, publicly available comprehensive final report will be weighed against the costs. In a few years, it will be possible to determine if these final reports have expanded the reach of each research study, whether they are used in systematic reviews, and how lessons learned from peer review of the final reports have changed the way that the institute does its work. For the present, it may be enough to hope that an openly accessible peer-reviewed comprehensive final research report will help to increase public trust in research. It is possible that the sponsors of the legislation were on to something important when they set the institute on this path. However, the realization of their vision is in its infancy and its putative benefits are largely speculative. There is still much to learn.
The human nose could have evolved to separate olfactory inputs to enhance stereo olfaction; as humans became more sedentary in the Neolithic, maybe other functions appeared (detecting disease in newly dense human settlements)
The navigational nose: a new hypothesis for the function of the human external pyramid. Lucia F. Jacobs. Journal of Experimental Biology 2019 222: jeb186924. February 6 2019, doi: 10.1242/jeb.186924
ABSTRACT: One of the outstanding questions in evolution is why Homo erectus became the first primate species to evolve the external pyramid, i.e. an external nose. The accepted hypothesis for this trait has been its role in respiration, to warm and humidify air as it is inspired. However, new studies testing the key assumptions of the conditioning hypothesis, such as the importance of turbulence to enhance heat and moisture exchange, have called this hypothesis into question. The human nose has two functions, however, respiration and olfaction. It is thus also possible that the external nose evolved in response to selection for olfaction. The genus Homo had many adaptations for long-distance locomotion, which allowed Homo erectus to greatly expand its species range, from Africa to Asia. Long-distance navigation in birds and other species is often accomplished by orientation to environmental odors. Such olfactory navigation, in turn, is enhanced by stereo olfaction, made possible by the separation of the olfactory sensors. By these principles, the human external nose could have evolved to separate olfactory inputs to enhance stereo olfaction. This could also explain why nose shape later became so variable: as humans became more sedentary in the Neolithic, a decreasing need for long-distance movements could have been replaced by selection for other olfactory functions, such as detecting disease, that would have been critical to survival in newly dense human settlements.
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ABSTRACT: One of the outstanding questions in evolution is why Homo erectus became the first primate species to evolve the external pyramid, i.e. an external nose. The accepted hypothesis for this trait has been its role in respiration, to warm and humidify air as it is inspired. However, new studies testing the key assumptions of the conditioning hypothesis, such as the importance of turbulence to enhance heat and moisture exchange, have called this hypothesis into question. The human nose has two functions, however, respiration and olfaction. It is thus also possible that the external nose evolved in response to selection for olfaction. The genus Homo had many adaptations for long-distance locomotion, which allowed Homo erectus to greatly expand its species range, from Africa to Asia. Long-distance navigation in birds and other species is often accomplished by orientation to environmental odors. Such olfactory navigation, in turn, is enhanced by stereo olfaction, made possible by the separation of the olfactory sensors. By these principles, the human external nose could have evolved to separate olfactory inputs to enhance stereo olfaction. This could also explain why nose shape later became so variable: as humans became more sedentary in the Neolithic, a decreasing need for long-distance movements could have been replaced by selection for other olfactory functions, such as detecting disease, that would have been critical to survival in newly dense human settlements.
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Human olfactory navigation
Olfaction is often underestimated as a sensory basis for navigation (Jacobs, 2012). This neglect is particularly acute in the study of human navigation (Jacobs et al., 2015).
This is partly because primates, and particularly humans, have
erroneously been assumed to have exceptionally poor olfactory abilities (Laska et al., 2000; McGann, 2017; Shepherd, 2004). Yet, in many species, including humans, the largest gene superfamilies are those for olfactory receptors (Hasin-Brumshtein et al., 2009). And while primates are indeed highly visual (Smith et al., 2007, 2014),
visual acuity does not preclude the use of olfaction for long-distance
movements in other highly visual animals such as birds (Wallraff, 2005).
Descriptive reports of humans using odors to navigate have a long history (Porteous, 1985; Gatty, 1983), especially in the visually impaired (Koutsoklenis and Papadopoulos, 2011),
although there are to date only two experimental studies of olfactory
navigation in humans. In the first study, humans were shown to
accurately follow an odor trail of chocolate across a grassy field, and
their accuracy was enhanced by stereo olfaction (Porter et al., 2007). In another study, humans were able to learn and map an arbitrary location in a room using only odor gradients (Jacobs et al., 2015).
Clearly,
the human ability to orient to odors is not as highly developed as that
of olfactory specialists, such as the domestic dog. First, the human
internal nasal chamber is smaller than expected for a mammal of its body
size (Zwicker et al., 2018).
Its chamber lacks an olfactory recess, a feature found in the domestic
dog that separates the olfactory air stream from the respiratory air
stream. The recess is thought to retard and enhance the processing of
air to extract odors (Craven et al., 2010, 2007).
But
to make the analogy with birds once again: just because human olfaction
is inferior does not mean it is not functional. Modern birds also have a
reduced olfactory system in comparison to their archosaur ancestors (Zelenitsky et al., 2011). Yet, bird olfactory bulb size may be adapted to different ecological niches (Corfield et al., 2015),
including long-distance travel: diverse bird species rely primarily on
olfaction for orientation during migration and experimental displacement
(Wallraff, 2005; Gagliardo, 2013; Holland et al., 2009; Wikelski et al., 2015).
Air-borne odors can be stable across time and hence may offer unique
value to navigators, as a long-distance sensory highway (Safi et al., 2016).
This property of air-borne odors could lead to selection for olfactory
navigation skills, even in highly visual and auditory species, such as
birds and bipedal apes.
Stereo olfaction
Comparative
studies can offer clues as to what properties of the human nose would
support such olfactory navigation. A primary function would be stereo
olfaction, or the spatial separation of paired sensors to increase the
accuracy of directional orientation, similar to stereo audition (von Békésy, 1964). von Békésy's (1964) hypothesis has been supported by studies from a wide range of invertebrate and vertebrate species: honey bee (Apis mellifera) (Martin, 1965), desert ant (Cataglyphis fortis) (Steck et al., 2010), fruit fly (Drosophila melanogaster) (Borst and Heisenberg, 1982), terrestrial snail (Achatina fulica) (Chase and Croll, 1981), giant garden slug (Limax maximus) (Gelperin, 1974), blacktip shark (Carcharhinus limbatus) (Gardiner et al., 2015) and sharks in general (Gardiner and Atema, 2010), brown bullhead catfish (Ictalurus nebulosus) (Bardach et al., 1967; Johnsen and Teeter, 1980), the bifurcated tongue of snakes (Schwenk, 1994), laboratory rat (Rattus norvegicus) (Rajan et al., 2006; Khan et al., 2012), eastern American mole (Scalopus aquaticus) (Catania, 2013), domestic dog (Canis lupus familiaris) (Craven et al., 2010) and human (Porter et al., 2007).
The manipulation of crossing the inputs also eliminates the ability to
orient in space to odors, both in animals with antennae (Martin, 1965) and in those with nares (Catania, 2013).
The
critical variable in stereo olfaction is the physical separation of the
catchment areas in the fluid, whether air or water, in which odorants
are suspended. Sensor mobility will be critical in determining the
volume of fluid sampled and the separation of the catchment areas, with
greater separation allowing for greater accuracy in orientation. For
example, a honey bee with two fixed antennae oriented less accurately to
an odor source than a bee with two mobile antennae (Martin, 1965). For vertebrates with nares, Stoddart (1979)
proposed that the key variable may instead be the length and
flexibility of the neck, suggesting this could explain why vertebrates
with less flexible necks, such as salamanders, have more widely spaced
nares. This increased nasal breadth would theoretically increase the
separation of the samples and hence compensate for the lack of head
mobility seen in vertebrates with less flexible necks (Stoddart, 1979).
The same reasoning has been used to study the separation of nostrils in
sharks such as the hammerhead shark, where computational models predict
that this separation increases the shark's accuracy in directional
orientation (Rygg et al., 2013; Gardiner and Atema, 2010).
A
third principle that has been proposed to enhance stereo olfaction, in
addition to using the movement of antenniform structures or increasing
the spatial separation of the nares, is the addition of a tube-like
vestibule to the nares. The use of tube noses to increase the accuracy
of stereo olfaction was first proposed by Stoddart (1979)
to explain the distribution of tube noses in several bat families
(Vespertilionidae subfamilies Nyctimeninae and Murininae; also in
Pteropodidae). A recent study of the physics of siphons offers direct
support for Stoddart's (1979)
hypothesis. When fluids are siphoned into a simple vertical tube, the
size and separation of the catchment area are determined by the velocity
of movement of the fluid and the height of the tube entrance from the
bed on which it stands. The greater the distance between the bed and the
siphon opening, the greater the spatial separation between the siphon
and the catchment area from which the siphon draws in fluids. There is a
further additive effect of fluid velocity, such that a tall tube,
pulling in fluid at a higher velocity, will be sampling from areas that
are farther apart than a siphon that is flush with the bed's surface or
is pulling in fluids at a lower velocity (True and Crimaldi, 2017).
This
result has important implications for understanding the adaptive
significance of tube noses. A longer tube would therefore increase the
spatial separation of odor samples, effectively increasing the distance
between the sensors. Additionally, the further separation of these
samples could be controlled by varying the intensity of the inhalation,
which would increase the velocity of the fluid, further separate the
catchment areas and thus further enhance stereo olfaction.
The
hypothesis that a tube nose enhances stereo olfaction may explain the
presence of this trait not only in bats but in birds. Tube-nosed
seabirds (Procellariiformes), which include shearwaters and albatrosses,
are well known for their ability to orient to odors, such as the krill
metabolites that are odor proxies for the presence of prey (Nevitt, 2008).
Tube-nosed seabirds are also thought to use olfaction to orient during
long-distance movements over water, in the absence of proximal visual
landmarks (Reynolds et al., 2015; Safi et al., 2016; Dell'Ariccia et al., 2014). In addition, the relative size of the olfactory bulbs is also larger in aquatic bird species (Corfield et al., 2015).
It is therefore possible that the demands faced by these seabirds have
led to the evolution of tube-like appendages to further separate
catchment areas and thus enhance olfactory navigation accuracy.
It
is interesting that tube noses have evolved in vertebrate taxa that
have evolved powered flight; relatively larger olfactory bulbs are
associated with increased space use in homing pigeons (Mehlhorn and Rehkämper, 2009), which navigate using odors (Wallraff, 2005).
Mapping an odor gradient may be done more accurately with the greater
number of samples possible over larger distances and hence may be more
valuable in species using long-distance movements, such as flying
insects and vertebrates (Jacobs and Menzel, 2014).
But this logic might also apply to terrestrial vertebrates that cover
large distances, e.g. cursorial vertebrates, such as carnivores and
humans; relatively larger olfactory bulbs are also found in terrestrial
carnivores that range over longer distances (Gittleman, 1991).
If increases in space use are associated with an increased use of
olfactory navigation, then this constraint may be relevant to the genus Homo, the first hominid to significantly increase space use and leave Africa (Antón et al., 2014). To answer this, we must first consider the question of the hominid nose in the context of other primates.
Olfaction in Homo
Perhaps external nose morphologies in primates, including Homo, can also be explained by the olfactory spatial hypothesis (Jacobs, 2012). As a catarrhine, the genus Homo
is one of the least olfactory primates, yet it is the only primate to
have evolved a large external nose. The only exception to this is the
catarrhine proboscis monkey (Nasalis larvatus), but in this
case the external nose is used by males in audiovisual communication and
does not appear to be specialized for olfaction (Koda et al., 2018).
The human external nose shows several unique features (Figs 1 and 2).
The external pyramid encloses generally inferior-orienting nares, a
trait not found in other great apes. The pyramid encloses the nares
within the alae nasi, the cartilaginous structures surrounding each
naris, separated by a third structure, the columella, a protrusion
between the two alae. No current hypothesis posits a respiratory
function for the alae nasi or columella.
Yet, such
structures could theoretically enhance olfaction, specifically stereo
olfaction. It is a testable hypothesis that the alae nasi could act as
tube noses, where a greater length of nasal vestibule would correspond
with greater separation of the catchment areas of inspired air. The
unique inferior orientation of the human nares, separated by the
columella, might also further separate the geometry of the catchment
areas during inspiration. Finally, the external pyramid itself could
increase the distance between the nares and, to a greater extent than
that seen in platyrrhine monkeys, could also enhance stereo olfaction.
These predictions could be tested by measuring the effect of nasal
metrics on a human's accuracy in orienting to an odor gradient. Using
standard methods, it should be possible to measure the effect of nasal
breadth on orientation accuracy to odors distributed in plumes. If
supported, then the navigational nose hypothesis could then be used to
address the remaining questions about the human external nose: why did
it appear when it did and why did nasal breadth and height subsequently
become so variable in modern humans?
Why did it evolve?
The external pyramid first appeared in Homo erectus (Franciscus and Trinkaus, 1988) (Fig. 6). Early Homo evolved in an increasingly unpredictable climate, with periods of great aridity, and forest habitats changing to grasslands (Antón et al., 2014). This change in climate and habitat structure led to selection in Homo
for a suite of traits to increase bipedal locomotory efficiency, such
as increased lower limb length, which allowed archaic humans to forage
more economically for widely dispersed resources (Steudel-Numbers, 2006; Bramble and Lieberman, 2004; Kuhn et al., 2016; Antón et al., 2014; Antón, 2012; Lieberman, 2011).
Fig. 6.
A reconstruction of Homo erectus. An early African Homo erectus, based on the skull KNM-ER 3733. Reproduced with permission from Gurche (2013).
Another major behavioral shift in Homo
at this time was an increase in carnivory, a shift that brought the
genus into direct competition with other mammalian carnivores (Churchill et al., 2016).
Given this interspecific competition between humans and other African
carnivores, it may be most fruitful to ask not what species humans are
most closely related to but to which species they are most ecologically
similar (Schaller and Lowther, 1969).
Humans were competing not only with cursorial carnivores but also with
olfactory specialists, species that used olfaction both to detect prey
and to orient in space. Carnivory, space use and olfactory bulb size may
be generally associated, as they are in terrestrial carnivores (Gittleman, 1986) and theropod dinosaurs (Zelenitsky et al., 2011, 2009); a similar association between carnivory, space use and olfaction may be seen in piscivorous birds (Wikelski et al., 2015) and sharks (Nosal et al., 2016).
Many African carnivores, such African lions (Panthera leo), wild dogs (Lycaon pictus) and spotted hyenas (Crocuta crocuta), are also highly social and hunt cooperatively (Smith et al., 2012). To compete in this environment, Homo sapiens also became, like their competitors, increasingly social, both hunting and breeding cooperatively (Hrdy, 2007).
The ability to hunt cooperatively, even before the development of
weaponry, changed many aspects of human socio-ecology. One behavior that
may have evolved at this time is the use of endurance pursuit to
capture large game (Carrier et al., 1984; Bramble and Lieberman, 2004). Endurance pursuit requires accurate spatial orientation, while tracking and returning to camp (Liebenberg, 2008). Such long-distance travel could also have selected for new navigational skills, such as olfactory navigation.
There
are additional navigational costs of carnivory beyond prey search and
handling. Carnivory carries with it a higher risk of foraging with zero
return than does foraging for non-meat foods. Hence, a primary mechanism
that has been shown to insure against such risk is to maintain large
social networks for food sharing (Grove, 2009).
In models of hunter–gatherer food sharing, greater cooperation and the
elimination of free riders is supported primarily by increased mobility (Lewis et al., 2014).
One of the true costs of carnivory may therefore be the need for
cooperative hunting and a widely dispersed social network for food
sharing, a behavior that would be made efficient with more accurate
spatial navigation.
Thus, olfactory navigation in Homo
could have represented an important new technical skill to increase the
efficiency of space use. This, in turn, would have selected for
mechanisms of stereo olfaction. It has also been proposed that it was
these adaptations for increased mobility that allowed archaic humans to
subsequently expand their species distribution (Kuhn et al., 2016); by 1.8 million years ago, Homo erectus had expanded out of Africa and become established in Georgia, Indonesia and possibly China (Antón et al., 2014).
Implications for sex differences
Both
the conditioning hypothesis and the navigational hypothesis posit that
the human external nose evolved as an adaptation for long-distance
movement. Thus, both hypotheses are predicated on the same ecological
demand: increased space use in an arid environment, necessitating
efficient conditioning and efficient navigation. Individual differences
in long-distance travel should therefore be reflected in nasal
structure.
Although men generally have larger range sizes than women (Gaulin, 1992), women may also forage over long distances (Jones et al., 1994).
Both may orient using odor and hence both could benefit from stereo
olfaction. The advantage of stereo olfaction may operate at different
spatial scales. In a landscape defined both by arrays of local landmarks
and distant cues that supply compass directions, females weight
proximal landmark cues more heavily than do males (Jacobs and Schenk, 2003; Chai and Jacobs, 2010; Bettis and Jacobs, 2013).
But it is not clear at what scale stereo olfaction is most effective
when tracking an odor plume; stereo olfaction is clearly important in
close-range orientation to odors (Catania, 2013; Porter et al., 2007).
Unlike a distant visual object that provides direction, plumes are not
contiguous in space but are a collection of discrete filaments (Murlis et al., 1992).
Thus, the local structure must be analyzed to deduce the global
structure. In this light, stereo olfaction might be valuable for the
analysis of both close and distant resources. The key factor is the
added value of a second sensor, as has been recently demonstrated in an
information theoretical model of optimal sampling for spatial
orientation in an empirically measured odor plume (Boie et al., 2018).
In short, the evolution of the external pyramid could have been equally
adaptive for women building high-resolution maps of resources near the
home base or men building low-resolution maps of distant resources.
The
use of long-distance foraging by men, in particular endurance pursuit,
may also explain sex differences in the relative size of the external
and internal nose. In a sample of European-descent Americans, men had
larger external noses, both absolutely and relative to body size, than
did women (Holton et al., 2014).
In a study using crania from diverse worldwide populations, males also
had a relatively larger nasal chamber volume than women, including
relative larger choanae, i.e. the posterior opening leading to the lungs
(Bastir et al., 2011).
The authors conclude that the larger internal chamber and choanae in
males would allow a greater volume of air to be conditioned during
exercise (Bastir et al., 2011).
A similar sex difference in internal nose dimensions has been
documented in imaging studies of German and Chinese adults, with men
showing a relatively larger nasal aperture than women (Schlager and Rüdell, 2015).
Such
sex differences in nose morphology could have arisen via sexual
selection in males for enhanced respiration during long-distance travel.
The choanae, for example, which are relatively larger in males, have a
purely respiratory function (Bastir et al., 2011). Thus, while the original appearance of the external nose in Homo erectus
may have been due to natural selection for increased space use in both
sexes of the species, other nasal structures could have been shaped by
sexual selection to enhance a male's ability to compete with other men,
such as in endurance pursuit. Male hunting skill in hunter-gatherer
societies can often be interpreted as a trait driven by female choice
and may be the product of both natural selection for foraging and sexual
selection for male–male competition (Hawkes and Bird, 2002).
Sexual
selection for navigation might also explain patterns in olfactory bulb
size. In a German sample, both absolute olfactory bulb size and
olfactory function developed gradually between the ages of 6 and 17 (Hummel et al., 2011).
It increased throughout adulthood to peak around age 40 and then
declined in both women and men, although the absolute size of the
olfactory bulb was consistently larger in men (Buschhüter et al., 2008). Forty is also the age at which mortality begins to increase in hunter–gatherers, peaking at a model adult death of 70 years (Gurven and Kaplan, 2007). Finally, olfactory bulb size is positively correlated with olfactory function (discrimination and threshold) in humans (Buschhüter et al., 2008; Hummel et al., 2011, 2013; Mazal et al., 2016; Seubert et al., 2013).
This suite of characters in human males could be an adaptation for
efficient foraging, a difference that might emerge at puberty and extend
over the peak hunting years, where accurate spatial orientation to
odors might be enhanced by a larger external nose, while the capacity
for oxygen exchange would be increased by a larger internal nasal
chamber and choanae.
In contrast, women might have
evolved a different suite of olfactory specializations, in addition to
the stereo olfaction afforded by an external nose. Women consistently
outperform men on measures of odor identification, for both social and
non-social odors (Doty and Cameron, 2009).
In a cross-cultural study of Japanese, Italian and German participants,
women more accurately identified the sex and individual identity of an
axillary odor (Schleidt et al., 1981); in a study of American college students, women could more accurately identify their own axillary odor than could men (Platek et al., 2001). Thus, in social encounters, women may have access to more accurate olfactory information than men.
These
sex differences could arise from sex differences in olfactory system
plasticity. The olfactory system changes rapidly (e.g. within months) if
given repeated exposures to an odor, even in humans that are initially
anosmic to the odorant (e.g. androsterone) (Wysocki et al., 1989). Repeated exposures both decreased the threshold of detection and increased absolute olfactory bulb size in the subject (Haehner et al., 2008). Even when only one nostril is exposed to the odor, both olfactory bulbs increased 11–13% in volume after 4 months (Negoias et al., 2017).
This effect of repeated exposure decreasing the threshold of detection
for an odor is significantly stronger in women than in men (Dalton et al., 2002).
Therefore,
experience-dependent sex differences in social experiences and hence
olfactory exposure could lead to the observed female advantage in
olfactory identification. These female advantages might also arise via
sexual selection, in this case selection for enhanced social
intelligence. This form of neural plasticity could also support related
skills, such as tracking and mapping the distribution of other
resources, e.g. food and medicinal plants, that could be identified most
accurately by odor. Relevant to this, a new study has demonstrated that
a human's ability to identify odors co-varies with their ability to
learn landmark locations in a virtual environment. These cognitive
skills also co-varied with the size and integrity of brain structures
involved in both spatial navigation (right hippocampus) and olfaction
(left orbitofrontal cortex) (Dahmani et al., 2018), in accordance with the olfactory spatial hypothesis (Jacobs, 2012).
This tight relationship between olfaction and spatial memory could have
evolved via selection for mapping resources via chemical cues.
The
predictions of these proposed sex-specific specializations, whether
long-distance travel in men or resource tracking in women, are amenable
to empirical testing. Re-framing the human external nose as an olfactory
structure could lead to new insights into human perception and brain
plasticity and their modulation by natural and sexual selection.
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