Heritability of sedentary behavior: Genetic factors explained 56% of the individual differences in objective sedentary behavior & 26% of the individual differences in self‐reported sedentary behavior

Heritability of objectively assessed and self‐reported sedentary behavior. Nienke M. Schutte  Charlotte Huppertz  Stieneke Doornweerd  Meike Bartels  Eco J.C. de Geus  Hidde P. van der Ploeg. Scandinavian Journal of Medicine & Science in Sports, March 18 2020. https://doi.org/10.1111/sms.13658

Abstract: Understanding the sources of the large individual differences in sedentary behavior is of great importance as this behavior is associated with pre‐mature mortality and non‐communicable diseases. Here, we report on the contribution of genetic and environmental factors to the variation in objectively assessed (accelerometer) sedentary behavior and self‐reported sitting and their shared genetic basis. In addition, the overlap of the genetic risk factors influencing sedentary time and moderate‐to‐vigorous physical activity (MVPA) was estimated. A sample of 800 individuals (twins and their siblings) was equipped with an Actigraph accelerometer for 7 days and reported on their sitting time and time spent on MVPA on those days using the IPAQ‐SF. Genetic factors explained 56% (CI: 44%, 65%) of the individual differences in objective sedentary behavior (Actigraph) and 26% (CI: 0%, 51%) of the individual differences in self‐reported sedentary behavior (IPAQ‐SF). A modest correlation (0.33) was found between these measures, which was for 45% accounted for by genetic influences. The genetic correlation was 0.49 reflecting a partly overlapping set of genes that influenced both measurements. A modest correlation (−0.27) between Actigraph‐derived sedentary time and MVPA was found, which was 13% accounted for by genetic effects. The genetic correlation was −0.31, indicating that there are overlapping genetic variants that increase sedentary time and decrease MVPA or vice versa. To conclude, more than half of the individual differences in objective sedentary time could be attributed to genetic differences, while for self‐reported sitting this was much lower. In addition, using objective measurements, this study confirms that sedentary time is not simply the inverse of MVPA. Future studies are needed to understand the pathways translating genomic variation into variation in these behaviors and how this knowledge might feed into the development of health promotion interventions.

4 DISCUSSION

The main aim of the current study was to extend the scarce literature on the heritability of objective sedentary behavior. A relatively large sample of adult male and female twins and their siblings was equipped with an Actigraph for 7 consecutive days and reported on their sitting time and time spent on MPVA activities. We showed that more than half of the individual differences in objectively measured sedentary time could be attributed to genetic differences (56%). This estimate is comparable to the previously reported estimate of 47% for sedentary time measured objectively using a combined heart rate and movement sensor in an older, mostly female population.15

The heritability estimate for self‐reported sitting time in Dutch adults was much lower (26%) than that for the objective measure, but in good keeping with the heritability of 35% for total self‐reported sitting time in a cohort of older (aged 53‐67) Finnish adults.11 The lower heritability of self‐reported sitting time might in part be explained by recall bias, social desirability bias, or other measurement bias, which in the model are part of the unique environmental component (E), thereby inflating the influence of E. The unstandardized environmental variance in self‐reported sitting time was indeed higher compared with the environmental variance component of objective sedentary time. Another explanation for the lower heritability of our self‐report measure compared with objectively measured sedentary time is that the IPAQ‐questionnaire assesses only sitting time, while objectively measured sedentary time will also include time lying down (daytime napping) and standing still.

A few attempts have been made to identify the genetic variants underlying the heritability of self‐reported sedentary behaviors. In the Québec Family Study, a variant of the melanocortin‐4 receptor (MC4R) gene was found to be associated with a combined measure of self‐reported sedentary time and physical inactivity28 and in the Framingham Heart study an association of the fat mass and obesity‐associated (FTO) gene with sitting time was reported.29 These candidate gene studies are now understood to have been underpowered and confirmation through meta‐analysis of genome‐wide association (GWA) studies in very large samples from multiple cohorts are direly needed.21 A GWA study using accelerometer data of ~100 000 participants from the UK Biobank cohort reported 4 loci for sedentary time (rs26579 near MEF2C‐AS2, rs25981 near EFNA5, rs1858242 near LOC105377146; and rs34858520 near CALN1).30

If self‐reported sitting time and objectively measured sedentary time could be safely mixed in meta‐analyses it would become easier to accrue the sample sizes needed to identify the many genetic variants that may play a role in this complex and likely polygenetic behavioral trait. This requires a significant overlap in the genetic variants that influence self‐reported and objectively measured sedentary time. Our results are mildly encouraging for such future endeavors. Previous studies had shown mixed results when comparing accelerometer‐based sedentary time to survey derived sedentary time ranging from poor to reasonably strong agreement.31, 32 At the phenotypic level, we find a significant but modest correlation of r = 0.33 which fits this pattern of results. However, a bivariate genetic decomposition of the phenotypic correlation showed that the genetic variants that are associated with self‐reported sitting are also associated with objectively measured sedentary behavior. Although the phenotypic correlation is modest only, the genetic correlation (rG = 0.49) might support meta‐analysis across both types of measures in genome‐wide gene‐finding studies; at least a part of the genetic variants relevant to sedentary behavior will be associated with both measures.

Recently, the Sedentary Behavior Research Network (SBRN; a network connecting sedentary behavior researchers and health professionals from around the world) updated its definitions on, among others, sedentary behavior and physical inactivity and thereby supported that an insufficient physical activity level is not the same as sedentary behavior.1 This idea is supported by the modest inverse correlations detected between objective sedentary time and MVPA in this study, matching those observed in earlier studies.16-18 This confirms that sedentary time is not simply the inverse of MVPA. Interestingly, the observed association between occupational sedentary time and occupational MVPA is −0.29, whereas the association between non‐occupational sedentary time and non‐occupational MVPA increases to −0.42, suggesting that outside work time, the association between MVPA and sedentary time is stronger. As a large portion of this is leisure time, it might be that when given the free choice, people who do more physical activity, also sit less.

When dividing total accelerometer wear time into occupational and non‐occupational time, the heritability estimate of occupational sedentary time (45%) is higher than the heritability estimate for non‐occupational sedentary time (28%). This was unexpected as sitting time at work was considered to be more under external environmental rather than under the internal control of behavioral disposition. However, sitting time is known to be strongly associated with type of work with white‐collars generally accumulating higher levels of sedentary behavior than blue collars.33 The type of work will be strongly dependent on educational attainment which has shown to be a heritable trait.34 Possibly, the genetic factors that are associated with educational attainment or other traits that co‐determine the employment setting might contribute to the variation in occupational sedentary time.

The heritability of objectively measured MVPA was 46%. This heritability is comparable to the previously reported estimates of 47% for objective MVPA, based on a combined heart rate and movement sensor15 and estimates of 55% and of 47% for MPA and VPA measured with an accelerometer.35 Self‐reported MVPA from the IPAQ showed a low heritability estimate (14%) and this echoes reports of low heritability of self‐reported MVPA in other adult samples.36, 37 Not surprisingly, we detected only a small correlation of r = 0.11 between objective and self‐reported MVPA. The latter may suffer from a larger measurement error because it includes a broad range of commuting, work, and household activities for which both intensity and duration may be hard to recall. Lee et al (2011) conducted a systematic review of the validity of the IPAQ‐SF and displayed that correlations between VPA/MPA/walking and objective standards showed great variability, ranging from −0.18 to 0.76.38 When self‐report is limited to voluntary leisure time activities of moderate‐to‐vigorous intensity, recall seems to be better. Regular exercise behavior, which is arguably easier to recall than all daily MVPA due to the mostly organized nature of exercise, has shown to be heritable in many adult twin and family samples with estimates higher than 40%.39, 40

Some limitations of this study must be noted. The twin sample used in the current study was relatively highly educated and 75% of the sample were female, which limits generalizability to the general population. This could have reduced the variance in our sample, and therefore have influenced our estimates. In addition, because of the small number of male participants we were unable to stratify our analyses by gender. Finally, as some people nowadays have flexible working hours (working part time or from home), it might be difficult to indicate their workday start and finishing times in the diary we used. Estimates of the genetic contribution to the (co)variance in occupational and non‐occupational sedentary time and MVPA might increase when a stricter distinction between working hours and non‐working hours is achieved as measurement error is reduced.

5 PERSPECTIVE

The majority of the variance in objectively measured sedentary time in a large sample of Dutch twins and their siblings could be explained by genetic factors. As opposed to general beliefs regarding the heritability of health behaviors, high heritability estimates do not signal that interventions are wasted efforts. Interventions on behavioral traits which are proven to be hereditary can have a large mean effect. Biological influences on the trait might explain the variation or individual differences in effect. The key is to identify the individuals who benefit the most from the intervention and exploit these biological influences on sedentary behavior in personalized or stratified interventions. Heritability studies serve to remind us that there is a biological component to individual differences in behavior. Sedentary time is not an exception. Interventions ignoring this underlying biology may prove less effective than those that build on furthering our understanding of the pathways from the genomic level to health behaviors.

Although surgeons & laypeople generally fail to recognize cosmetic surgery benefits beyond mere aesthetics, men & women bragging about cosmetic surgeries are deemed as higher in status; women gain in attractiveness

Folwarczny, Michal, and Tobias Otterbring. 2020. “Cosmetic Surgeries as Conspicuous Consumption: Disclosing Information About Having Undergone Cosmetic Surgery Signals Social Status.” PsyArXiv. December 17. doi:10.31234/osf.io/n4p37

Abstract: Do patients incur cosmetic surgery risks solely for aesthetic reasons, or do they draw additional, status-related benefits? Like other species, humans strive to attain high status in hierarchies as it helps them solve challenges linked to survival and reproduction. Cosmetic surgeries are costly, both bodily and financially. Organisms employ such seemingly self-handicapping actions to signal status. Across a series of studies (N = 1276) on UK and US samples, we demonstrate that although surgeons and laypeople generally fail to recognize cosmetic surgery benefits beyond mere aesthetics, men and women bragging about cosmetic surgeries are deemed as higher in status. Moreover, for women—but not men—status inferences are partially driven by attractiveness perceptions, consistent with an evolutionary account. However, contrary to what evolutionary theories predict, both sexes are keener on cosmetic surgeries after evaluating attractive opposite-sex models. Thus, people may "use the knife" to signal status, especially when mating motives are salient.

Helpers anticipated less appreciation for partial help than help-seekers felt in receiving it

Halfway to My Request Is Not Halfway to My Heart: Underestimating Appreciation for Partial Help. Yilu Wang, Xiaofei Xie. Personality and Social Psychology Bulletin, December 17, 2020. https://doi.org/10.1177/0146167220975276

Abstract: When being asked for help, people sometimes can only offer part of what is requested (i.e., partial help). The present research investigates whether helpers can accurately forecast how much help-seekers appreciate this understudied form of assistance. From multiple helping scenarios and a face-to-face interaction, we demonstrate an asymmetry in helpers’ and help-seeker’s appraisals of partial help: Helpers anticipated less appreciation for partial help than help-seekers felt in receiving it. This asymmetry arose from helpers’ greater valuation of helping outcomes over intentions to be helpful than help-seekers’. Accordingly, when helpers’ intentions were discounted, this asymmetry no longer persisted. Another account—helpers feel worse for breaking norms of helping than help-seekers—was not supported. We discuss several directions for future research on the psychology of partial prosocial behaviors.

Keywords: helping, help-seeking, social prediction, prosocial behavior

Early blindness does not critically impact on the development of the “social brain,” with social tasks performed on the basis of auditory or tactile information driving consistent node activations like those of the sighted

Social cognition in the blind brain: A coordinate‐based meta‐analysis. Maria Arioli  Emiliano Ricciardi  Zaira Cattaneo. Human Brain Mapping, December 15 2020. https://doi.org/10.1002/hbm.25289

Abstract: Social cognition skills are typically acquired on the basis of visual information (e.g., the observation of gaze, facial expressions, gestures). In light of this, a critical issue is whether and how the lack of visual experience affects neurocognitive mechanisms underlying social skills. This issue has been largely neglected in the literature on blindness, despite difficulties in social interactions may be particular salient in the life of blind individuals (especially children). Here we provide a meta‐analysis of neuroimaging studies reporting brain activations associated to the representation of self and others' in early blind individuals and in sighted controls. Our results indicate that early blindness does not critically impact on the development of the “social brain,” with social tasks performed on the basis of auditory or tactile information driving consistent activations in nodes of the action observation network, typically active during actual observation of others in sighted individuals. Interestingly though, activations along this network appeared more left‐lateralized in the blind than in sighted participants. These results may have important implications for the development of specific training programs to improve social skills in blind children and young adults.

4 DISCUSSION

The study of the neural bases of social cognition in the blind brain has been somehow neglected, with only a few studies specifically investigating whether and how the lack of visual input affects the functional architecture of the “social brain.” Some studies showed similar patterns of brain activity in early blind and sighted individuals during tasks tapping on social cognition abilities (Bedny et al., 2009; Ricciardi et al., 2009), while other studies suggested that social brain networks develop differently following early visual deprivation (Gougoux et al., 2009; Holig et al., 2014). These inconsistencies reported in the neuroimaging literature on social processing in blind individuals may also reflect possible confounds associated with individual studies, for example, the influence of experimental and analytic procedures as well as that of the small sample sizes (Carp, 2012). Moreover, the effects reported by individual studies are harder to generalize to the entire target group (here, the early blind), regardless the specific procedures used (Muller et al., 2018).

In light of this, we pursued a meta‐analytic approach to isolate the most consistent results in the available literature, controlling for possible confounding effects via stringent criteria for study selection. In particular, we aimed to investigate: (a) the neural coding of others' representation in early blind individuals, and (b) the specific brain regions recruited in early blind compared with sighted control individuals, during social processing of others. Although we could count only on a low number of contrasts, preventing more detailed analyses such as a direct comparison of nodes of the social brain possibly differently engaged by auditory and haptic inputs, our sample is in line with current recommendations for ALE meta‐analyses (Eickhoff et al., 2016; Muller et al., 2018).

Our findings demonstrate that the regions typically associated with the key nodes of the AON mediate social cognition abilities in early blind individuals on the basis of non‐visual inputs, as they do during actual observation of others in sighted individuals (Gardner et al., 2015). In particular, we found consistent overlapping activations in the middle temporal gyrus bilaterally, alongside the left fusiform gyrus and the right superior temporal gyrus and finally in the right inferior frontal gyrus of early blind individuals during others' processing. The bilateral activation of the middle temporal gyrus has been previously reported for the AON in a quantitative meta‐analysis on more than 100 studies in sighted individuals (Caspers et al., 2010). Moreover, similar results, including right frontal activation, are reported in a meta‐analysis investigating brain regions showing mirror properties through visual and auditory modalities in sighted individuals (Molenberghs, Cunnington, & Mattingley, 2012).

Of note, we found stronger consistent responses in the AON in the early blind as compared to sighted subjects. This is not surprising, since the studies we included in the meta‐analysis mostly employed auditory inputs (~90% of the studies, only two studies using haptic stimuli) that are the typical stimuli on which blind individuals rely on in social interactions, whereas sighted individuals are mainly guided by visual cues. This may also account for the different pattern of lateralization observed in the activation of the AON in blind and sighted individuals, with the former showing more consistent activations in the left hemisphere particularly in the middle temporal gyrus and fusiform gyrus, while the reverse comparison highlighted the activation of the right part of the middle and superior temporal cortex. The different pattern of hemispheric lateralization may depend on the high familiarity that blind individuals have in recognizing human actions or emotions on the basis of auditory (and haptic) stimuli, with prior evidence suggesting that action familiarity is associated with increasing activity in left part of the AON (Gardner et al., 2015; Ricciardi et al., 2009).

An additional analysis carried out on the whole sample of participants (regardless visual experience) confirmed the common activation in a right temporal cluster, comprising the STG, the TPJ and the MTG regions. This cluster appears to be consistently engaged in both groups during social processing and activations in these regions are likely to play a more general function in the perception of socially relevant stimuli, which is not bound to visual experience (Fairhall et al., 2017). These results fit with the involvement of the right STG and TPJ in a variety of social‐cognitive processes (Bahnemann, Dziobek, Prehn, Wolf, & Heekeren, 2010; Yang, Rosenblau, Keifer, & Pelphrey, 2015), such as biological motion perception (Beauchamp, Lee, Haxby, & Martin, 2003; Grossman et al., 2000; Peelen, Wiggett, & Downing, 2006), mentalizing (Schneider, Slaughter, Becker, & Dux, 2014; Wolf, Dziobek, & Heekeren, 2010), and emotion attribution to others on the basis of both visual and auditory/verbal information (e.g., Alba‐Ferrara, Ellison, & Mitchell, 2012; Ferrari, Schiavi, & Cattaneo, 2018; Gamond & Cattaneo, 2016; Lettieri et al., 2019; Redcay, Velnoskey, & Rowe, 2016; Sliwinska & Pitcher, 2018). These data suggest a two‐stage process in which the STS underpins an initial parsing of a stream of information, whether auditory or visual, into meaningful discrete elements, whose communicative meaning for decoding others' behavior and intentions involves more in‐depth analysis associated with increased activation in the TPJ node (Arioli & Canessa, 2019; Bahnemann et al., 2010; Redcay, 2008). Ethofer et al. (2006) showed that the pSTS is the input of the prosody processing system and represents the input to higher‐level social cognitive computations, associated with activity in the action observation system (Gardner et al., 2015), as well as in the mentalizing system (Schurz, Radua, Aichhorn, Richlan, & Perner, 2014). Accordingly, using visual stimuli Arioli et al. (2018) pointed to the pSTS as the input for the social interaction network, which includes key nodes of both action observation and theory of mind networks. Thus, the STS/TPJ regions may represent a domain‐specific hub associated with the analysis of the meaning of others' actions, regardless of the stimulation modality, and highly interconnected with the action observation and the mentalizing networks.

The lack of activation of the parietal cortex in the early blind, with the parietal cortex being another key node of the AON in sighted individuals, is possibly due to the low number of studies specifically focused on hand representation in our database (see Pellijeff, Bonilha, Morgan, McKenzie, & Jackson, 2006; 3/17, see Table 1). Indeed, Caspers et al. (2010) reported that only observation of hand actions was consistently associated with activations within parietal cortex, the observation of non‐hand actions was not. Moreover, although Ricciardi et al. (2009) reported a parietal activation in blind participants during auditory presentation of hand‐executed actions, this activation was much less extensive (particularly in the superior parietal cortex) in the blind compared to sighted controls. Another possible explanation for the lack of parietal activation in the blind in our meta‐analysis (also possibly accounting for the results by Ricciardi et al., 2009) is that the activation within the parietal part of the AON may be mainly driven by object‐related representations (Caspers et al., 2010), which are not present in several of the experiments included in the present analysis. In turn, our studies focused mainly on voice processing (6/17), and in part on face/body representation (4/17), this probably being responsible for the consistent activation we reported in the fusiform gyrus. Indeed, voice processing has been found to activate the fusiform face area in blind individuals (i.e., Fairhall et al., 2017).

The findings of this meta‐analysis suggest that the AON can develop despite the lack of any visual experience, with information acquired in other sensory modalities allowing an efficient representation of other individuals as agents with specific beliefs and intentions (vs. objects moved by physical forces). These results may explain why early blind individuals are able to efficiently interact in the social context and to learn by imitation of others' (e.g., Gamond et al., 2017; Oleszkiewicz et al., 2017; Ricciardi et al., 2009). Our findings suggest that regions of the social brain may work on the basis of different sensory inputs, depending on which sensory modality is available. Moreover, our findings are consistent with the results of a recent meta‐analysis by Zhang et al. (2019) and with prior fMRI studies with blind individuals in the social domain (e.g., Bedny et al., 2009; Ricciardi et al., 2009) suggesting that brain regions that are consistently recruited for different functions in sighted individuals, such as the dorsal fronto‐parietal network for spatial function and ventral occipito‐temporal network for object function, and—as shown here—the AON for social function, maintain their specialization despite the lack of a normal visual experience. This observation on the “social blind brain” is in line with the current, more general perspective on the blind brain that undergoes a functional reorganization due to the lack of visual experience, but whose large‐scale architecture appears to be significantly preserved (e.g., Ricciardi, Papale, Cecchetti, & Pietrini, 2020).

Interestingly, we did not find evidence for any cross‐modal consistent recruitment of the occipital cortex by social tasks in this meta‐analysis. Cross‐modal plasticity typically refers to activation of the occipital cortex of the early blind in response to input acquired in other sensory modalities, like hearing and touch (for reviews, Merabet & Pascual‐Leone, 2010; Singh, Phillips, Merabet, & Sinha, 2018; Voss, 2019), and may account (at least in part) for the superior perceptual abilities of blind subjects in the spared sensory modalities (e.g., Battal, Occelli, Bertonati, Falagiarda, & Collignon, 2020; Bauer et al., 2015). Alternatively, recruitment of the occipital cortex in the blind has been proposed to also subserve high‐level (cognitive) processing (e.g., Amedi, Raz, Pianka, Malach, & Zohary, 2003; Bedny, Pascual‐Leone, Dodell‐Feder, Fedorenko, & Saxe, 2011; Lane, Kanjlia, Omaki, & Bedny, 2015) suggesting that cortical circuits that are thought to have evolved for visual perception may come to participate in abstract and symbolic higher‐cognitive functions (see Bedny, 2017). Indeed, recent evidence has shown that during high‐level cognitive tasks (i.e., memory, language and executive control tasks), there is an increased connectivity between occipital cortex and associative cortex in the lateral prefrontal, superior parietal, and mid‐temporal areas (Abboud & Cohen, 2019), with these regions being also possibly involved in social perception (Caspers et al., 2010). In line with this, we would have expected social tasks to drive activations in the occipital cortex. This was not the case. The only region that showed a sort of cross‐modal response was the fusiform face area, in the ventral stream, probably guided by a high number of studies included in our meta‐analysis focusing on voice processing (cf. Holig et al., 2014; von Kriegstein, Kleinschmidt, Sterzer, & Giraud, 2005). In this regard, it is also worth noting that haptic perception by blind individuals of facial expressions and hand shapes (Kitada et al., 2013, 2014) as well as whole‐body shape recognition via a visual‐to‐auditory sensory substitution device (SSD; Striem‐Amit & Amedi, 2014) led to activations in face and body‐dedicated circuits in the fusiform gyrus, showing that these dedicated circuits develop even in the absence of a normal visual experience. Our meta‐analysis shows that processes related to representation of others do not recruit the occipital cortex in the early blind, suggesting that differently to other cognitive tasks, social tasks may be mediated by higher‐level regions without the need to recruit additional occipital resources. Even if this might be related to the experimental heterogeneities that we highlighted above, the lack of a consistent recruitment of occipital cortex for social tasks we reported contributes to a better understanding of the functional role of “visual” areas in the blind brain.

In conclusion, our findings support the view that the brain of early blind individuals is functionally organized in the same way of the brain of sighted individuals although relying on different types of input (auditory and haptic) (see Bedny et al., 2009; Ricciardi et al., 2009). In the social domain, this may have important implications for educational programs for blind children. Early blindness may indeed predispose to features of social isolation, including autism (e.g., Hobson et al., 1999; Jure, Pogonza, & Rapin, 2016). It is therefore important to develop training administration guidelines specifically for persons with visual impairment (Hill‐Briggs, Dial, Morere, & Joyce, 2007). In this regard, an interesting approach would be to develop ad hoc auditory/haptic virtual reality social cognition trainings for children with blindness or severe visual impairment, as already employed with autistic children and young adults (e.g., Didehbani, Allen, Kandalaft, Krawczyk, & Chapman, 2016; Kandalaft, Didehbani, Krawczyk, Allen, & Chapman, 2013). Consistent evidence suggests that audio‐based virtual environments may be effective for the transfer of navigation skills in the blind (Connors, Chrastil, Sanchez, & Merabet, 2014; Sanchez & Lumbreras, 1999), and haptic virtual perception may be a valid and effective assistive technology for the education of blind children in domains like math learning (e.g., Espinosa‐Castaneda & Medellin‐Castillo, 2020). This approach—especially audio‐based virtual environments—may thus be extended to the social domain to allow the safe and non‐threatening practice of particular social skills in an educational setting. In this respect, and considering the importance for visually impaired children to study in a mainstream school (e.g., Davis & Hopwood, 2007; Parvin, 2015), school‐based social cognitive interventions on the social participation of children with blindness or severe visual impairment would be particularly critical, with teachers and peers being involved responding and reinforcing blind children' initiated interactions. A detailed description of the neuro‐cognitive processes underlying social cognition skills in blind individuals is thus critical to tailor training protocols aiming at targeting specific neuro‐cognitive functions. This may have also a translational clinical impact on the development of non‐invasive advanced SSDs able to translate social cues that are only visually available (such as face expressions, gestures and body language) to auditory or tactile feedback that can be processed by the intact social brain of visually deprived individuals, in terms of more abstract conceptual signals (see Cecchetti, Kupers, Ptito, Pietrini, & Ricciardi, 2016; Striem‐Amit & Amedi, 2014). These devices may help blind individuals in their interactions both in the physical and virtual (i.e., meetings via Skype, Meet or others) social world.

Kangaroos never domesticated can ask humans for help

Kangaroos display gazing and gaze alternations during an unsolvable problem task. Alan G. McElligott, Kristine H. O'Keeffe and Alexandra C. Green. The Royal Society Biology Letters, December 16 2020. https://doi.org/10.1098/rsbl.2020.0607

Abstract: Domestication is generally assumed to have resulted in enhanced communication abilities between non-primate mammals and humans, although the number of species studied is very limited (e.g. cats, Felis catus; dogs, Canis familiaris; wolves, Canis lupus; goats, Capra hircus; horses, Equus caballus). In species without hands for pointing, gazing at humans when dealing with inaccessible food during an unsolvable task, and in particular gaze alternations between a human and the unsolvable task (considered forms of showing), are often interpreted as attempts at referential intentional communication. We report that kangaroos, marsupial mammals that have never been domesticated, actively gazed at an experimenter during an unsolvable problem task (10/11 kangaroos tested), thus challenging the notion that this behaviour results from domestication. Nine of the 10 kangaroos additionally showed gaze alternations between the unsolvable task and experimenter. We propose that the potential occurrence of these behaviours displayed towards humans has been underestimated, owing to a narrow focus on domestic animals, as well as a more general eutherian research bias.

Fellatio among male sanctuary-living chimpanzees during a period of social tension

Fellatio among male sanctuary-living chimpanzees during a period of social tension. Authors: Jake S. Brooker et al. Behaviour, Dec 15 2020. https://doi.org/10.1163/1568539X-bja10053

Abstract: Same-sex sexual behaviour has been documented across the animal kingdom, and is thought to reflect and enhance dyadic cooperation and tolerance. For instance, same-sex fellatio — the reception of a partner’s penis into another’s mouth — has been reported in several mammalian species other than humans. Although same-sex sexual behaviour is observed in our close relatives, the chimpanzees, fellatio appears to be very rare — as yet there are no published reports clearly documenting its occurrence. At Chimfunshi Wildlife Orphanage in Zambia, we observed an instance of fellatio occurring during a post-conflict period between two adult male chimpanzees (born and mother-reared at the sanctuary) where one of the males was the victim. We discuss this event with respect to the putative functions of homosexual behaviour in great apes. Given its rarity in chimpanzees, this fellatio between adult males also highlights the apparent behavioural flexibility present in our close relatives.

Keywords: chimpanzee; fellatio; same-sex sexual behaviour; homosexual behaviour; sanctuary; behavioural flexibility; social tension

4. Discussion

In this report, we described an instance of same-sex fellatio occurring between two sanctuary-living adult male chimpanzees. Although fellatio has been observed in other mammals (Ogawa, 2006; Tan et al., 2009; Sergiel et al., 2014; Sugita, 2016), including captive/semi-captive bonobos (de Waal, 1988; Clay, personal observation) and chimpanzees (Heesen, personal communication) it has not yet been reported among adult chimpanzees during social tension, with two previous reports noting the occurrence of oral-genital contact among play in immature chimpanzees (Savage & Malick, 1977; Savage-Rumbaugh & Wilkerson, 1978). Moreover, while bonobos habitually engage in diverse same-sex sexual behaviour, fellatio appears to be rare and constrained to play contexts involving immatures (de Waal, 1988; Clay, personal observation). To our knowledge, fellatio has not been reported to occur in post-conflict affiliative interactions among either chimpanzees or bonobos. This observation thus provides relevant insights into the potential diversity of its functions in our closest living relatives.

Homosexual interactions, such as those reported here between Max and David, have been hypothesised to reinforce same-sex alliances and increase the propensity to support and cooperate (Kirkpatrick, 2000; Moscovice et al., 2019). Creating such connections may facilitate alliance formation and provide greater opportunities for future cooperation and support during agonism between non-kin. As a low-ranking chimpanzee, it is possible that Max’s request for fellatio in this case may have been driven by a motivation to associate with potential coalition partners, with genital contacts having been shown to facilitate coalitionary support in bonobos, the close relative of chimpanzees (Moscovice et al., 2019). As our closest phylogenetic relatives, studying genital contacts in chimpanzees, including fellatio, in specific contexts may provide clarity on the evolutionary origins of same-sex sexual behaviour within and between the sexes.

Our observation may also reflect fellatio serving a reassurance and alliance testing function by a subordinate male, akin to genital touches and mounting commonly observed between wild male chimpanzees during socially tense periods such as before boundary patrols and intergroup encounters (Wittig et al., 2016; Samuni et al., 2019). It has been proposed that engaging in intimate, risky behaviour such as fellatio can be used to test social relationships and tolerance (Kirkpatrick, 2000).

Chimpanzees are behaviourally innovative and spontaneously develop unique behaviour that may culturally transmit, even if such actions appear to lack adaptive benefits (van Leeuwen et al., 2014). As chimpanzees are not known to habitually engage in same-sex sexual interactions, Max’s repeated attempts to initiate genital contact for reassurance may also represent a behavioural innovation. Observing Max’s group in varying contexts would be necessary to detect whether he possesses a more general tendency for same-sex sexual interactions. Further, longitudinal investigations may show that idiosyncratic sexual behaviour, such as fellatio, is culturally transmitted over time.

Although the functions of fellatio remain to be explored in great apes, its initiation by a lower ranking to a dominant male in a socially tense context makes a novel contribution to the literature. Given the apparent overlaps between this behaviour and genital contacts occurring among the close sister species, the bonobos, systematically comparing sexual behaviours during periods of social tension between Pan would provide greater clarity on how sexual behaviours may be adapted and deployed to fortify and repair social relationships.

The More Who Die, the Less We Care: Evidence from Natural Language Analysis of Online News Articles and Social Media Posts

The More Who Die, the Less We Care: Evidence from Natural Language Analysis of Online News Articles and Social Media Posts. Sudeep Bhatia et al. Risk Analysis, August 25 2020. https://doi.org/10.1111/risa.13582

Abstract: Considerable amount of laboratory and survey‐based research finds that people show disproportional compassionate and affective response to the scope of human mortality risk. According to research on “psychic numbing,” it is often the case that the more who die, the less we care. In the present article, we examine the extent of this phenomenon in verbal behavior, using large corpora of natural language to quantify the affective reactions to loss of life. We analyze valence, arousal, and specific emotional content of over 100,000 mentions of death in news articles and social media posts, and find that language shows an increase in valence (i.e., decreased negative affect) and a decrease in arousal when describing mortality of larger numbers of people. These patterns are most clearly reflected in specific emotions of joy and (in a reverse fashion) of fear and anger. Our results showcase a novel methodology for studying affective decision making, and highlight the robustness and real‐world relevance of psychic numbing. They also offer new insights regarding the psychological underpinnings of psychic numbing, as well as possible interventions for reducing psychic numbing and overcoming social and psychological barriers to action in the face of the world's most serious threats.

Chimpanzees have diverse behavioral repertoires yet lack more complex cultures than humans; invention and social information use in a cumulative task and chimpanzees fail at that

Why do chimpanzees have diverse behavioral repertoires yet lack more complex cultures? Invention and social information use in a cumulative task. Gillian L. Valeai et al. Evolution and Human Behavior, December 16 2020. https://doi.org/10.1016/j.evolhumbehav.2020.11.003

Abstract: Humans are distinctive in their dependence upon products of culture for survival, products that have evolved cumulatively over generations such that many cannot now be created by a single individual. Why the cultural capacity of humans appears unrivalled in the animal kingdom is a topic of ongoing debate. Here we explore whether innovation and/or social learning propensities may constrain the ability of one of our closest living relatives, chimpanzees (Pan troglodytes), to master an extractive foraging and tool-use task designed to afford opportunities for cumulative culture to develop. We further explore the potential demographic characteristics associated with novel task solutions. Chimpanzees (N = 53) were inventive, flexibly exploring the novel task, albeit complex inventions were rare and shaped by prior individual experience with similar tool-use tasks. However, they displayed no evidence of cumulative cultural learning. Communities displayed richer behavioral repertoires and had greater task success than chimpanzees tested in an asocial control condition, but their solution complexity did not surpass what individuals invented. The lack of social transmission of complex and beneficial solutions in contexts like those we studied provides one explanation for the limited cumulative culture observed in this species.

Keywords: CultureCumulative cultureCumulative cultural evolutionInnovationSocial learningTool use

Why Has Burglary Declined by 80 Percent Across Four Decades in the US? Household security, largely absent in the 1970s, improved gradually over time (juveniles finding burglary increasingly difficult)

Farrell, Graham. 2020. “Why Has Burglary Declined by 80 Percent Across Four Decades in the United States? Evidence Relating to the Security Hypothesis.” SocArXiv. January 18. doi:10.31235/osf.io/c78wz

Abstract: Residential burglary imposes significant financial and emotional costs upon victims and society overall. Yet residential burglary in the US has declined by over 80 percent across the last four decades, representing a major social phenomenon that remains largely unexplained. International research indicates a need for investigation of the security hypothesis. Here, 50 years of burglary studies are examined chronologically. A consistent narrative emerges which indicates that household security, largely absent in the 1970s, improved gradually over time. Improvement occurred via three mechanisms: the increased prevalence, quality, and routine use of security fixtures and fittings. In addition, crime displacement declined as fewer household presented easy crime opportunities, and burglars’ average age increased ( juveniles finding burglary increasingly difficult). The likelihood that 50 years of diverse evidence points in the same direction by chance, and without significant contrary evidence, seems remote. Hence the conclusion is that gradual household security improvements played a central role in the decline in residential burglary over time. Implications for theory, policy, and further research are identified.

COVID-19: the emoji density (average number of emojis per tweet) and the relative popularity of specific emojis have changed

How has the coronavirus (COVID-19) pandemic affected global emoji usage? Anwesha Das. Journal of Human Behavior in the Social Environment, Dec 14 2020. https://doi.org/10.1080/10911359.2020.1838383

Abstract: Over the past few decades, emojis have emerged as a popular form of non-linguistic expression in computer-mediated communication. Various factors have been known to affect emoji usage patterns (such as age, gender, platform diversity etc.). The aim of the current study is to explore if the onset of the coronavirus pandemic (2019–20) has affected emoji usage patterns across various countries. The present study was conducted on two sets of tweets, collected before (July, 2019) and during the pandemic (March, 2020). The results suggest that although the usage of specific emojis has not changed noticeably (that is, the popular emojis mostly remained the same), the emoji density (average number of emojis per tweet) and the relative popularity of specific emojis have changed. This could potentially point toward a sense of insufficiency of emojis to express the sentiments associated with the pandemic.

Discussions and conclusions

Emoji usage and their patterns can provide significant insight into human behavior in CMC. In addition, the scope of understanding the different factors affecting emoji usage is vast.

In the present work, emoji usage was compared between two datasets (one collected before and the other after the start of the pandemic), and different characteristic parameters were explored for the purpose of this comparison.

Current results do not show any significant shift in the use of the popular emojis before and after the start of pandemic. It was observed that across all four country-clusters, the most popular emojis more or less remained the same. In addition to this, no emoji that can be associated with the pandemic was present in the top 10 emojis used for each cluster, suggesting that on a general scale, the pandemic does not seem to have altered the most commonly used emojis. Further, the average sentiment score of the emojis used (by country-cluster, for the top 5 emojis) remained approximately the same before and after the start of the pandemic.

However, an interesting point to note here is that across the first three clusters (with the maximum number of COVID-19 patients), the relative popularity of some of the most popular emojis dropped after the start of the pandemic. For example, in cluster 1, the “tears of joy emoji” (the most popular emoji across all clusters), made up 34.36% of all the emojis used, whereas after the start of the pandemic, it made up only 14.69%. A similar pattern is seen in cluster 2 as well, where initially the “tears of joy” emoji makes up 17.72% of all emojis, whereas it makes up only 5.00% after the start of the pandemic. In cluster 3, the values are 7.46 and 4.59 before and after the start of the pandemic, respectively, that is the difference closes in. In cluster 4, this difference almost levels out. A similar pattern is also observed amongst a few of the other top 5 emojis. As mentioned earlier in this paper, the emoji usage density dropped for 75% of the countries (by approximately 40%) in the first three clusters. Hence, indicating that the average usage of emojis by countries which are most affected by the pandemic dropped.

Although this difference is subtle, this could potentially indicate toward a shift in general public sentiment—a possible explanation being that there is a sense of insufficiency in emojis being able to convey the emotions associated with the pandemic. Another explanation could be that people associate emojis to a (comparatively) lighthearted conversation (Danesi, 2016), whereas the pandemic calls for more serious expressions, where emojis may be inadequate.

Nevertheless, it is important to mention here that a number of other factors could possibly affect global emoji usage and emoji usage amongst country-clusters (say clusters having countries with vastly differing economies etc.). The current study aimed to look at only one such possible factor, namely, the onset of the COVID-19 pandemic.

Dishonest behavior is positively correlated with happiness; happiness may provide the cognitive flexibility necessary to reframe and rationalize dishonest acts

Do Happy People Cheat Less? A Field Experiment on Dishonesty. Erez Siniver. Journal of Behavioral and Experimental Economics, December 15 2020, 101658. https://doi.org/10.1016/j.socec.2020.101658

Highlights

• An experiment is designed to examine the effect of happiness on dishonest behavior.

• Dishonest behavior is found to be positively correlated with happiness.

• The positive relationship between dishonesty and happiness is not gender driven.

Abstract: Results of an experimental study designed to examine the effect of happiness on dishonest behavior are reported and analyzed. Passersby on the streets of Tel Aviv were asked to answer the Oxford Happiness Questionnaire (OHQ), which contains 29 multiple-choice questions for measuring Subjective Well-Being (SWB). Each question is answered according to a uniform six-point Likert scale. After filling out the questionnaire, they were invited to perform the Fischbacher and Follmi-Heusi (2013)’s die-under-the-cup (DUTC) task, which incentivizes dishonest behavior. Past research has found a positive relationship between a person's level of honesty and their reported SWB. However, that result is based entirely on a subject's responses to a direct-question survey that simply asks whether he behaves ethically. The present study examines the relationship between dishonest behavior and SWB based on experimental data. Happiness was found to be positively correlated with dishonest behavior, implying that happy people cheat more than unhappy people. A possible explanation for this unexpected result is that happiness may provide the cognitive flexibility necessary to reframe and rationalize dishonest acts. This may pave the way for the commission of dishonest acts by altering how people evaluate the moral implications of their behavior.

Key words: HappinessSubjective Well-BeingEthicsDishonestyLyingDie-Under-the-Cup Task

Find higher fertility among men with higher cognitive ability among Swedish men using taxation & conscription registers; low income & low cognitive ability independently predict low fertility & high childlessness

Do income and marriage mediate the relationship between cognitive ability and fertility? Data from Swedish taxation and conscriptions registers for men born 1951–1967. Martin Kolk, Kieron Barclay. Intelligence, Volume 84, January–February 2021, 101514. https://doi.org/10.1016/j.intell.2020.101514

Highlights

• We find higher fertility among men with higher cognitive ability among Swedish men using population-level taxation and conscription registers

• Low income and low cognitive ability independently predict low fertility and high childlessness

• Strong evidence of lower access to marriage and reproduction among low status men in contemporary Sweden

Abstract: Recent evidence suggests a positive association between fertility and cognitive ability among Swedish men. In this study we use data on 18 birth cohorts of Swedish men to examine whether and how the relationship between cognitive ability and patterns of childbearing are mediated by income, education and marriage histories. We examine whether the expected positive associations between cognitive ability and life course income can explain this positive association. We also explore the role of marriage for understanding the positive gradient between cognitive ability and fertility. To address these questions we use Swedish population administrative data that holds information on fertility histories, detailed taxation records, and data from conscription registers. We also identify siblings in order to adjust for confounding by shared family background factors. Our results show that while cognitive ability, education, income, marriage, and fertility, are all positively associated with each other, income only explains a part of the observed positive gradient between fertility and cognitive ability. We find that much of the association between cognitive ability and fertility can be explained by marriage, but that a positive association exists among both ever-married and never-married men. Both low income and low cognitive ability are strong predictors of childlessness and low fertility in our population. The results from the full population persist in the sub-sample of brothers.

Keywords: FertilityChildlessnessCognitive abilityIncomeSweden

6. Discussion

In our paper, we show that while income is strongly associated with cognitive ability, men with below average cognitive ability have fewer children, even after adjusting for income. We also find that these differences are magnified for childlessness, and are also very strong for entry into marriage. Consistent with previous research, we find that income and fertility are very strongly associated (Chudnovskaya, 2019; Kolk, 2019), but that the relationship between cognitive ability and fertility persists net of the mediation of income. This is particularly true at lower income levels. Men with low cognitive ability who are above the median in cumulative income between age 18 and 45 have approximately the same number of children as men who score highly on cognitive ability. However, men with low cognitive ability are much less likely to find themselves in the top half of the cumulative income distribution. Among ever-married individuals, the association between cognitive ability and fertility is strongly attenuated, and only really suggests lower fertility among men with the lowest scores on cognitive ability. When comparing full biological brothers with each other, we find a strong positive fertility and cognitive ability gradient even after adjusting for income. Overall, our results indicate that the primary reason that we observe low fertility among men with lower cognitive ability is because of their failure to attract a partner for stable unions for childbearing. In addition to confirming previous findings on cognitive ability and fertility in Sweden (Kolk & Barclay, 2019), the findings of this study provide evidence for the importance of partnership formation for fertility, as well as showing that the intelligence-fertility association persists even after taking cumulative income into account.

Another intriguing empirical pattern that we have observed is that, although men with high cognitive ability have more children overall, men of average cognitive ability had more children than men with high cognitive ability scores among those who never married. These never-married men with high cognitive ability are too few to affect the population-level intelligence-fertility gradient, but may indicate a sub-population that either voluntarily abstains from childbearing and marriage, or in other ways have life trajectories that are associated with high education and income but not traditional patterns of family formation. In our full population analyses, when adjusting for cumulative income, we find that the men with the highest cognitive ability scores have slightly lower fertility and higher childlessness than men with median cognitive ability scores. After adjusting for income we observe slightly lower fertility among high IQ never-married men (left-panels of Fig. 6, Fig. 7), as well as slightly lower fertility among men with high cognitive ability (see Fig. 1). However, our finding that higher cognitive ability men have higher childlessness and lower fertility than men with similar incomes but average cognitive ability is not replicated in sibling comparison models.

In our sibling comparison models we consistently observe lower fertility among men in the bottom half of the cognitive ability distribution. The difference between our population level models and the sibling models is intriguing. Although the results from our population level models are key to understanding how cognitive ability may be distributed in the following generation (though without data on women we cannot speculate about this), the sibling comparison models effectively adjust for all factors shared in the family of origin. It is certainly possible that the results in the full population are confounded by factors that are jointly associated with both cognitive ability as well as fertility outcomes, for example negative experiences in early adulthood such as health shocks or substance abuse.

We believe that our study highlights the importance of examining and interpreting gross associations between cognitive ability and fertility by taking account of the associations between cognitive ability and mediating dimensions of social status and partnership formation. The sociological and demographic literature suggests great variation across the West in the associations between income and fertility, and education and fertility. The findings from our Swedish data may not generalize to other countries. In other high-income countries, the interrelationships between education, income, marriage, and fertility, differ in important ways from Sweden, and our results may to some extent be contingent on the aggregate positive relationships between status and marriage and family formation in Sweden. Nevertheless, we think that the fertility disadvantage of very low cognitive ability men is likely widespread across OECD contexts and that using datasets where such individuals are fully included is important if researchers are to be able to make population-level inferences. Future research on cognitive ability and fertility is therefore advised to pay careful attention to contemporary research in family sociology, demography, and economics on the overall relationship between status and fertility in the focal society. Importantly, the associations between income and fertility and education and fertility typically differ by gender. Unfortunately, we cannot examine any gender differences in the intelligence-fertility gradient in Sweden as we have male-only conscription data.

Our findings also contribute towards the increasing evidence for social polarization of childbearing in many Western countries. We find that the proportion childless and the proportion that never-marry is very substantial among men with lower cognitive ability. We find large separate effects where both low income and low cognitive ability are each strongly associated with a higher probability of childlessness and low completed fertility. When a man has both low income and low cognitive ability, fertility is even lower. This corresponds to the findings from a growing literature that shows that men with low income, low levels of education, worse health, and low cognitive ability, are much less likely to find a childbearing partner in Scandinavia (Barclay & Kolk, 2020; Jalovaara et al., 2019; Jalovaara & Fasang, 2020; Kolk, 2019). Fertility in Scandinavia has traditionally been characterized by relatively small social differences between groups. Our findings of differences by cognitive ability in probabilities of childlessness and ever-marriage of 20 to 30 percentage points clearly show that partnership and childbearing are increasingly less likely for many men with low cognitive ability in contemporary Sweden.