Formal religious practices statistically predicted increased severity of suicidal thoughts, while belief in God did not; religious conflict was also associated with increased severity of suicidal thoughts

Rabasco, A., & Andover, M. (2021). The relationship between religious practices and beliefs and suicidal thoughts and behaviors among transgender and gender diverse adults. Psychology of Religion and Spirituality, Nov 2021. https://doi.org/10.1037/rel0000453

Abstract: Transgender and gender diverse (TGD) people are at heightened risk for suicidal thoughts and behaviors (James et al., 2016). Some studies have found that religious practices and beliefs are positively associated with suicidal thoughts or behaviors among TGD individuals (Gibbs & Goldbach, 2015), while other studies have found a negative association (Grossman et al., 2016) or no relationship (Yüksel et al., 2017). In order to better understand the relationship between religion and suicidal thoughts and behaviors among TGD people, the present study investigated the relationship between religious practices, belief in God, and religious conflict, and suicidal thoughts and behaviors. TGD adults (N = 180) were recruited and completed questionnaires online assessing religious practices, religious conflict, and suicidal thoughts and behaviors. It was found that formal religious practices statistically predicted increased severity of suicidal thoughts, while belief in God did not. Religious conflict was also associated with increased severity of suicidal thoughts. Specifically, participants who reported currently holding religious beliefs that were not accepting of their gender identity had significantly higher severity of suicidal thoughts compared to participants who reported currently holding religious beliefs that were accepting of their gender identity. No relationship between religious practices and beliefs and suicidal behaviors emerged. These findings underscore the nuanced relationship between religion and suicidality among TGD people. They also point to the potential for religious communities to help reduce suicidal ideation among TGD members by fostering personal religious beliefs that are accepting of diverse gender identities.

Countries and Cultural Differences in the Stigma of Mental Illness: The East–West Divide

Countries and Cultural Differences in the Stigma of Mental Illness: The East–West Divide. Anne C. Krendl, Bernice A. Pescosolido. Journal of Cross-Cultural Psychology, February 21, 2020. https://doi.org/10.1177/0022022119901297

Abstract: Mental illness is a global public health crisis. Although rates of untreated cases stand as a primary problem, stigma is a significant obstacle. Yet, global differences in levels and roots of stigma remain poorly understood. Using the Stigma in Global Context–Mental Health Study (SGC-MHS) data, we analyzed data on two components of stigma—prejudice and discriminatory potential—attached to clinically diagnostic cases of depression and schizophrenia. We examined whether stigma was higher in the East than West. Furthermore, we hypothesized that the link between prejudice and discriminatory potential in the East was due, in part, to cultural differences in the attributions about mental illness. With SGC-MHS’ nationally representative vignette data from over 11,000 respondents in 11 relevant countries (four Eastern, seven Western), analyses replicated past research of higher levels of stigma and more moral attributions in Eastern countries, particularly for depression. Moreover, prejudice-related disclosure spillover concerns predicted discriminatory potential (social distance) in the East, but not the West; this was driven by a greater emphasis on moral attributions in the East. Finally, exploratory analyses found that Western respondents endorsed higher discrimination for minority (vs. majority) group members with mental illness. In Eastern countries, the same pattern emerged for schizophrenia, but the reverse occurred for depression—greater stigma for majority as compared with minority group members. Together, these findings suggest that cultural differences in the sources of prejudice and attributions about the etiology of mental illness contribute, at least in part, to global differences in the profile of stigma.

Keywords: mental health stigma, global, double jeopardy, depression, schizophrenia, mental illness

Paper suggests older humans are actually evolved to be much more physically active for longer than we usually are, & that physical activity is therefore extremely protective against chronic disease and extends life & health

The active grandparent hypothesis: Physical activity and the evolution of extended human healthspans and lifespans. Daniel E. Lieberman et al. Proceedings of the National Academy of Sciences, December 14, 2021 118 (50) e2107621118; https://doi.org/10.1073/pnas.2107621118

Abstract; The proximate mechanisms by which physical activity (PA) slows senescence and decreases morbidity and mortality have been extensively documented. However, we lack an ultimate, evolutionary explanation for why lifelong PA, particularly during middle and older age, promotes health. As the growing worldwide epidemic of physical inactivity accelerates the prevalence of noncommunicable diseases among aging populations, integrating evolutionary and biomedical perspectives can foster new insights into how and why lifelong PA helps preserve health and extend lifespans. Building on previous life-history research, we assess the evidence that humans were selected not just to live several decades after they cease reproducing but also to be moderately physically active during those postreproductive years. We next review the longstanding hypothesis that PA promotes health by allocating energy away from potentially harmful overinvestments in fat storage and reproductive tissues and propose the novel hypothesis that PA also stimulates energy allocation toward repair and maintenance processes. We hypothesize that selection in humans for lifelong PA, including during postreproductive years to provision offspring, promoted selection for both energy allocation pathways which synergistically slow senescence and reduce vulnerability to many forms of chronic diseases. As a result, extended human healthspans and lifespans are both a cause and an effect of habitual PA, helping explain why lack of lifelong PA in humans can increase disease risk and reduce longevity.

Keywords: physical activityexerciselifespanhealthspanevolution

594,196 fifteen-year-olds, 77 countries: girls experience less physical & verbal victimization & have stronger anti-bullying attitudes; physical victims have less –not more--anti-bullying attitudes

Marsh, Herb, Jiesi Guo, Philip D. Parker, Reinhard Pekrun, Geetanjali Basarkod, Theresa Dicke, Roberto H. Parada, et al. 2021. “An Integrative Review of Cross-national Comparisons of Verbal, Relational, and Physical Peer Victimization: Gender Differences, Paradoxical Anti-bullying Attitudes, and Well-being.” PsyArXiv. November 23. doi:10.31234/osf.io/qfmek

Abstract: Current victimization studies and meta-analyses are based mainly on a unidimensional perspective in a few developed OECD countries. This provides a weak basis for generalizability over multiple victimization (relational, verbal, physical) components and different countries. We test the cross-national generalizability (594,196 fifteen-year-olds; 77 countries) of competing victimization models. In support of our three-component model, differentiating the multiple components of victimization facilitated understanding: gender differences (girls experience less physical and verbal victimization and stronger anti-bullying attitudes, but relational differences are small); paradoxical anti-bullying attitudes (physical victims have less –not more--anti-bullying attitudes); and well-being (policy/practice focuses primarily on physical victimization, but verbal and relational victimization effects are larger). These key findings provide theoretical advances with implications for policy, practice, and intervention.

Smell loss was quantified as the single best predictor of COVID19; this specificity was used to create a novel tool, the ODoR-19 (Olfactory Determination Rating Scale in COVID-19) scale, for use in rapid screening

Massively collaborative crowdsourced research on COVID19 and the chemical senses: insights and outcomes. Elisabeth M. Weir et al. Food Quality and Preference, November 26 2021, 104483. https://doi.org/10.1016/j.foodqual.2021.104483

Highlights

• The Global Consortium of Chemosensory Research (GCCR) was founded in Spring 2020.

• Results from GCCR research on COVID19 and the chemical senses are summarized.

• Some open science approaches used by the GCCR are highlighted.

Abstract: In March 2020, the Global Consortium of Chemosensory Research (GCCR) was founded by chemosensory researchers to address then emerging reports of unusual smell and taste dysfunction arising from the SARS-CoV-2 pandemic. Over the next year, the GCCR used a highly collaborative model, along with contemporary Open Science practices, to produce multiple high impact publications on chemosensation and COVID19. This invited manuscript describes the founding of the GCCR, the tools and approaches it used, and a summary of findings to date. These findings are contextualized within a summary of some of the broader insights about chemosensation (smell, taste, and chemesthesis) and COVID19 gained over the last 18 months, including potential mechanisms of loss. Also, it includes a detailed discussion of some current Open Science approaches and practices used by the GCCR to increase transparency, rigor, and reproducibility.

Keywords: GCCRCOVID19anosmiatasteopen sciencesmell

3. Summary of some initial findings from the GCCR

While all the GCCR papers to date have resulted in key insights on COVID-19 and its effects on all three chemosesenses, the first GCCR paper (Parma et al., 2020) provided especially vital information. This analysis asked a simple question: “did self-assessment of taste, smell, and chemesthesis during illness differ from retrospective assessment of chemosensory function prior to illness?” This was determined by asking participants to rate their smell ability on a 0-100 visual analog scale (VAS) during their illness, as well as retrospectively rating their smell ability prior to their illness on the same scale – the difference between these two self-reported ratings was taken as a measure of lost function. Parallel questions were asked for taste and oral chemesthesis. Using data from ∼4000 participants collected in 10 languages, Parma et al. found that a majority of COVID19 positive participants reported a significant drop in ability to smell, with a mean drop of almost 80 points relative to their ability to smell prior to their illness. This suggested anosmia was a characteristic symptom of COVID19 (Parma et al., 2020), confirming the anecdotal reports noted above. Taste and oral chemesthesis were also significantly blunted in individuals with COVID19, with mean decreases of ∼70 and ∼37 points, respectively (Parma et al., 2020). Notably, impairment of chemesthesis was typically accompanied by either taste and/or smell loss, although in other participants, taste and smell loss appeared when normal chemesthesis was preserved. Because the survey was based on self-report of function, rather than assessment with controlled stimuli, reports of taste loss may not actually reflect taste loss (which is very rare with other viral illnesses), but may instead reflect a common taste/smell confusion among the general public (and some clinicians; see (Boltong, Keast, & Aranda, 2011)). However, the survey also asked about alteration of specific taste qualities (i.e., salty, sweet, sour, bitter, and umami/savory) with check-all-that-apply (CATA) question, and significant deficits were also observed. Changes in specific taste qualities were consistently reported by ∼37 to 45% of participants for sweet, sour, salty and bitter; reports were slightly lower for umami/savory (∼25%) but this may reflect lack of familiarity with the concept of umami and/or translation difficulty, rather than any specific robustness of this quality against loss. As noted by Green (Green, 2020), a high endorsement of altered function was reported for salty (∼45%), a quality that is not commonly attributed to odors (in contrast to sweetness or sourness). Collectively, this suggested that reported taste loss is not merely an artifact arising from a taste/smell confusion, an observation that was subsequently confirmed by multiple studies that assess taste function using various stimuli, rather than relying on self-report. Although the quality of these studies is highly variable on balance, they support the view that some of taste loss reported by those with COVID19 reflects true disruption of the taste system.

Aligning with self-reports, over a dozen studies using various stimuli (e.g., strips, homemade solutions) indicate taste loss occurs with COVID19. Although the measures of taste in these studies were often ad hoc (given the urgency of the pandemic), it is still evident that true taste loss (and not merely a semantic taste-flavor confusion) is a characteristic feature of COVID-19. That is, validated methods, like those developed as part of the NIH Toolbox (Coldwell et al., 2013) or used for the National Health and Nutrition Examination Survey (NHANES) Chemosensory Exam (Rawal, Hoffman, Honda, Huedo-Medina, & Duffy, 2015), have not been employed to date. This is wholly understandable given the needs of clinicians and researchers to collect data as quickly as possible during early days of the pandemic, often when few resources were available. Moving forward, a prime goal of chemosensory scientists should be to apply rigorous test methods to study COVID-19 taste loss, especially in those with post-acute sequelae of COVID-19 (PASC). Still, the primary message here is that the preponderance of evidence, even with imperfect measures, indicates taste loss is a verifiable symptom of COVID-19.

COVID19 associated anosmia also appears to be distinct from the transient anosmia experienced with respiratory illnesses such as the common cold. With the common cold, smell loss typically co-occurs with a lack of airflow, as a consequence of nasal congestion – that is, volatile odor active molecules cannot reach receptors on the olfactory epithelium at the top of the nasal cavity, as mucus and/or swelling block the nasal passages. In the first GCCR survey, participants were also asked to report apparent congestion, via a rating of perceived nasal blockage, where a higher score indicated more blockage. The mean pre-COVID19 nasal blockage was almost zero, whereas the mean reported blockage during COVID19 was ∼22 points higher, suggesting some participants experienced some blockage. However, comparison of the distribution of nasal obstruction ratings before and after COVID19 indicated that many participants had little to no blockage during COVID19 (Parma et al., 2020), and more critically, principal components analysis (PCA) indicated ratings of blockage were independent to ratings of smell and taste loss. This implies acute change in olfactory function for COVID19 positive individuals was not attributable to simple conductive losses. Although mechanisms for changes in taste, smell, and chemesthesis remain to be elucidated, these early data suggested disruption of chemosensory function was a hallmark indicator of COVID19 infection.

After reporting that smell and taste loss were cardinal symptoms of COVID19, the GCCR analyzed a second data tranche from the same survey that included ∼15,000 responses in 23 languages collected between 7 April 2020 and 2 July 2020. Besides fully replicating findings from the first study among non-overlapping participants (n=4,825), the new report compared responses in COVID19 positive and negative individuals, all with recent respiratory symptoms (Gerkin et al., 2021). The primary goal was to try to predict COVID19 diagnosis from all reported symptoms, regardless of whether they were chemosensory in nature.

Using both categorical and binary responses, chemosensory symptoms were found to be more strongly associated with COVID-19 diagnosis than fever, cough, or any other non-chemosensory symptoms, including difficulty breathing. In fact, self-reported smell ability during illness was the single most predictive factor for COVID-19, followed by self-reported taste ability during illness. These results highlight the importance of chemosensory changes during COVID19 infection. As anticipated, smell, taste, and chemesthesis were reported to be greatly reduced for COVID19 positive individuals compared to COVID19 negative individuals. Also, this analysis confirmed that nasal obstruction was not predictive of COVID19. Overall, non-chemosensory symptoms were less specific symptoms than smell loss, allowing those with COVID19 to be distinguished from other respiratory illnesses. In summary, smell loss was quantified as the single best predictor of COVID19, and this specificity was used to create a novel tool, the ODoR-19 (Olfactory Determination Rating Scale in COVID-19) scale, for use in rapid screening (Gerkin et al., 2021).

Interoceptive accuracy, the ability to correctly perceive internal signals arising from the body: Men are better with heart signals; both sexes fail w/gastric or respiratory signals

Sex differences in interoceptive accuracy: A meta-analysis. Freya Prentice, Jennifer Murphy. Neuroscience & Biobehavioral Reviews, November 25 2021. https://doi.org/10.1016/j.neubiorev.2021.11.030

Highlights

• Sex differences in interoceptive accuracy are reported, but results are mixed.

• This meta-analysis sought to confirm the presence or absence of sex differences.

• Poor cardiac accuracy on counting and discrimination tasks was observed in females.

• Effects were less stable for non-cardiac due to varied methods and sample sizes.

• Results were mixed for respiratory, and no differences were observed for gastric.

Abstract: Interoceptive accuracy, the ability to correctly perceive internal signals arising from the body, is thought to be disrupted in numerous mental and physical health conditions. Whilst evidence suggests poorer interoceptive accuracy in females compared to males, raising the possibility that interoceptive differences may relate to sex differences in mental and physical health, results concerning sex differences in interoceptive accuracy are mixed. Given such ambiguity, this meta-analysis aimed to establish the presence or absence of sex differences in interoceptive accuracy across cardiac, respiratory, and gastric domains. A review of 7956 abstracts resulted in 93 eligible studies. Results demonstrated superior accuracy in males across cardiac, but not gastric, tasks, while findings on respiratory tasks were mixed. Effect sizes were consistent across cardiac tasks, but instability and/or moderate heterogeneity was observed across other domains, likely due to the small number of eligible studies. Despite such limitations, results indicate the possibility of sex differences across interoception tasks and domains. Methodological limitations concerning the influence of physiological factors, and directions for future research are discussed.

Keywords: interoceptive accuracycardiac interoceptionrespiratory interoceptiongastric interoceptionsex differencesmeta-analysis

In contrast to psychophysiological reactions, self-reported emotional reactions to threatening stimuli are reliably associated with ideology

The Psychophysiology of Political Ideology: Replications, Reanalyses, and Recommendations. Mathias Osmundsen, David J. Hendry, Lasse Laustsen, Kevin B. Smith, and Michael Bang Petersen. The Journal of Politics, Nov 2021. https://www.journals.uchicago.edu/doi/10.1086/714780

Abstract: This article presents a large-scale, empirical evaluation of the psychophysiological correlates of political ideology and, in particular, the claim that conservatives react with higher levels of electrodermal activity to threatening stimuli than liberals. We (1) conduct two large replications of this claim, using locally representative samples of Danes and Americans; (2) reanalyze all published studies and evaluate their reliability and validity; and (3) test several features to enhance the validity of psychophysiological measures and offer a number of recommendations. Overall, we find little empirical support for the claim. This is caused by significant reliability and validity problems related to measuring threat sensitivity using electrodermal activity. When assessed reliably, electrodermal activity in the replications and published studies captures individual differences in the physiological changes associated with attention shifts, which are unrelated to ideology. In contrast to psychophysiological reactions, self-reported emotional reactions to threatening stimuli are reliably associated with ideology.

Children’s gender accurately identified from their speech: Since young boys & girls overlap almost entirely in gross acoustic cues that drive gender perception for adults, results suggest accuracy based on transmission of more subtle gender information

Perception of gender in children's voices. Santiago Barreda and Peter F. Assmann. The Journal of the Acoustical Society of America 150, 3949 (2021), Nov 23 2021. https://doi.org/10.1121/10.0006785

Abstract: To investigate the perception of gender from children's voices, adult listeners were presented with /hVd/ syllables, in isolation and in sentence context, produced by children between 5 and 18 years. Half the listeners were informed of the age of the talker during trials, while the other half were not. Correct gender identifications increased with talker age; however, performance was above chance even for age groups where the cues most often associated with gender differentiation (i.e., average fundamental frequency and formant frequencies) were not consistently different between boys and girls. The results of acoustic models suggest that cues were used in an age-dependent manner, whether listeners were explicitly told the age of the talker or not. Overall, results are consistent with the hypothesis that talker age and gender are estimated jointly in the process of speech perception. Furthermore, results show that the gender of individual talkers can be identified accurately well before reliable anatomical differences arise in the vocal tracts of females and males. In general, results support the notion that the transmission of gender information from voice depends substantially on gender-dependent patterns of articulation, rather than following deterministically from anatomical differences between male and female talkers.

Narcissistic Individuals Exhibit Poor Recognition Memory; narcissistic individuals’ excessive self-focus predicted this memory deficit

Narcissistic Individuals Exhibit Poor Recognition Memory. Miranda Giacomin, Christopher Brinton, Nicholas O. Rule. Journal of Personality, November 19 2021. https://doi.org/10.1111/jopy.12690

Abstract: Here, we examine face memory among individuals who are self-focused and care little about others’ needs: grandiose narcissists. Given narcissistic individuals’ excessive self-focus and tendency to disregard the needs of others, they may struggle to recognize faces and their surrounding environment. Indeed, narcissistic individuals demonstrated worse recognition memory than non-narcissistic individuals in recognition memory tests for faces (Studies 1 [N = 332] and 2 [N = 261]). This difference also occurred for nonsocial stimuli (i.e., objects, houses, cars), suggesting a broad recognition deficit (Study 3A [N = 178], 3B [N = 203], 3C [N = 274]). Narcissistic individuals’ excessive self-focus predicted this memory deficit (Study 4 [N = 187]). Grandiose narcissism may therefore influence visual recognition memory, highlighting the potential for future research linking personality and cognitive performance.

Perceptions of early news coverage about COVID-19: Citizens had positive attitudes toward their own Covid-19 news sources, but were critical about the news sources others were using to get information about the virus

My pandemic news is better than yours: audience perceptions of early news coverage about Covid-19. Mallory R. Perryman. Communication Research Reports, Nov 23 2021. https://doi.org/10.1080/08824096.2021.2007070

Abstract: This study focuses on how American audiences perceived news coverage during the early days of the Covid-19 pandemic in the United States. Through a survey-experiment of news consumers (N = 767) over a three-day period in mid-March 2020, this study shows that citizens had positive attitudes toward their own Covid-19 news sources, but were critical about the news sources others were using to get information about the virus. Data reveal evidence of presumed media influence, where audiences believed others’ health behaviors were being influenced by pandemic news.

Keywords: Presumed media influencemedia perceptionsperceived news habitsthird-person effectfirst-person effectpresumed behavior

Umbrella review: Most adolescents experienced no or negligible effects of social media use on mental health

Social media use and its impact on adolescent mental health: An umbrella review of the evidence. Patti M. Valkenburg, Adrian Meier, Ine Beyens. Current Opinion in Psychology, Volume 44, April 2022, Pages 58-68. https://doi.org/10.1016/j.copsyc.2021.08.017

Abstract: Literature reviews on how social media use affects adolescent mental health have accumulated at an unprecedented rate of late. Yet, a higher-level integration of the evidence is still lacking. We fill this gap with an up-to-date umbrella review, a review of reviews published between 2019 and mid-2021. Our search yielded 25 reviews: seven meta-analyses, nine systematic, and nine narrative reviews. Results showed that most reviews interpreted the associations between social media use and mental health as ‘weak’ or ‘inconsistent,’ whereas a few qualified the same associations as ‘substantial’ and ‘deleterious.’ We summarize the gaps identified in the reviews, provide an explanation for their diverging interpretations, and suggest several avenues for future research.

Keywords: Meta-reviewSocial networking sitesSNSFacebookInstagramWell-beingDepressionDepressive symptoms

Discussion

In this umbrella review, we synthesized the results of 25 recent reviews into the effects of SMU on adolescent mental health. Given that adolescents’ SMU is continually changing, it is important to provide regular research updates on this use and its potential effects. In addition to the many important future directions raised in earlier reviews, we discuss three crucial avenues for future research.

Defining SMU, defining mental health

First, future research needs to consistently define the predictors and outcomes under investigation. Several reviews regularly switched between terms such as digital media use, technology use, and SMU without specifying to which media activities these terms refer. In some studies, emailing and gaming were part of the definitions of SMU, whereas others covered only time spent on SNSs. Such imprecise definitions may greatly hinder our understanding of the effects of SMU on mental health because different types of SMU may lead to different effects on mental health outcomes. For example, time spent on SNS is associated with higher levels of depression [17], whereas emotional connectedness to SNS (‘intensity of use’) [15] and the number of friends on SNS [16] are unrelated to depression. In the world of SM, everything is rapidly new and rapidly old, and, therefore, it is all the more important to define the specific types of SMU under investigation and to hypothesize how and why these types of SMU could affect mental health outcomes.

Likewise, in several reviews, both mental health and well-being were used as catchall terms that were left undefined, which sometimes led to the discussion of a potpourri of cognitive and affective outcomes that each deserve to be investigated in their own right. Our umbrella review confirmed that similar types of SMU can lead to opposite associations with different mental health outcomes [17]. Both SMU and mental health are highly complex constructs. Although most studies have focused on the associations of SMU with depression or depressive symptoms, all other constituent mental health outcomes, including their risk (e.g. loneliness) and resilience factors (e.g. self-esteem), also deserve our full research attention, provided that they are clearly defined and demarcated from other mental health outcomes.

Capturing the content and quality of SM interactions

Several reviews have pointed at a need to move away from possibly biased self-report measures toward more objective measures of SMU use, such as log-based measures of time spent with SM. Indeed, self-report measures of time spent with SM correlate only moderately with similar log-based measures [42,43]. However, although log-based measures are often seen as the gold standard, they have their own validity threats, such as technical errors and the erroneous tracing of SM apps running in the background when the screen is turned off [42,43]. This means that the modest correlations between self-reports and log-based measures could be due to validity issues of self-reports but also of objective measures. More importantly, though, most log-based measures only capture time spent with SM apps, which is just as crude a predictor of mental health as comparable self-report measures. If logging measures only reiterate the ‘screen time’ approach of most self-report research, they provide only a limited way forward.

To arrive at a true understanding of the effects of SMU on mental health, future research needs to adopt measures that capture adolescents' responses to specific content or qualities of SM interactions. In experimental settings, this can be realized by using mock SM sites, such as the Truman Platform (https://socialmedialab.cornell.edu/) or the mock SM site developed by Shaw et al. [44]. In non-experimental settings, there are three approaches that can be combined with survey or experience sampling studies: (1) The ‘Screenomics’ approach developed by Reese et al. [45], which entails end-to-end software that randomly collects screenshots of adolescents’ smartphones, and extracts text and images; (2) phone-based mobile sensing [46], which captures sound via the microphone and text entered via the keyboard; and (3) analysis of SM ‘data download packages’ [47], the archives of SM interactions that each SM user is allowed to download. While each of these methods is promising, they require sophisticated technical skills and specific expertise. Therefore, they can best be achieved in collaborative interdisciplinary projects, which are also better equipped to realize larger samples.

Understanding inconsistent interpretations

Although the majority of the reviews concluded that the reported associations of SMU with mental health were small to moderate, some others interpreted these associations as serious [30], substantial [48] or detrimental [25]. Such disagreeing interpretations can also be witnessed in three recent publications on SMU and mental health by Twenge et al. [49], Orben and Przybylski [3], and Kreski et al. [50], all relying on the same UK-based data set. Such divides in interpretations of the same modest effect sizes are certainly not new in the media effects field. For example, as of the 1980s, there has been a fierce debate among scholars about the effects of game violence on aggression (e.g. see the dispute in Psychological Bulletin about whether this effect is trivial or meaningful [51,52]). Oftentimes, the involved scholars do not disagree that much about the size of the reported effects but just on how to interpret them.

What has often been ignored in such debates is that the effect sizes are just what they are: statistics observed at the aggregate level. Such statistics are typically derived from heterogeneous samples of adolescents who may differ greatly in their susceptibilities to the effects of environmental influences in general [53] and media influences in particular [54]. After all, each adolescent is subject to unique dispositional, social-context, and situational factors that guide their SMU and moderate its effects [55]. Such person-specific antecedents and effects of SMU cannot be captured by the aggregate-level statistics that have been reported in the majority of empirical studies and reviews, including the current one.

If we accept the propositions of media-specific susceptibility theories [54], it is plausible to assume that both optimistic and pessimistic conclusions about the effects of SMU are valid — they just refer to different adolescents. In fact, recent studies that have adopted an idiographic (i.e. N = 1 or person-specific) media effects paradigm [56] have found that a small group of adolescents experienced negative effects of SMU on well-being (around 10–15%) and another small group experienced positive effects (also around 10%–15%). Reassuringly though, most adolescents experienced no or negligible effects [57].

A person-specific approach to media effects requires a large number of respondents and a large number of within-person observations per respondent. Indeed, statistical power is expensive. However, due to rapidly advancing technological (e.g. phone-based experience sampling methods) and methodological developments (e.g. N = 1 time series analyses), such approaches are increasingly within everyone's reach, especially when researchers pool resources in interdisciplinary teams. A person-specific media effects paradigm may not only help academics resolve controversies between optimistic and pessimistic interpretations of aggregate-level effect sizes, but it may also help us understand when, why, and for whom SMU can lead to positive or negative effects on mental health. And above all, it may help us facilitate personalized prevention and intervention strategies to help adolescents maintain or improve their mental health.

Politically-motivated reasoning is similar for both men and women, but only men find it particularly attractive to believe that they outperform others

Gender differences in motivated reasoning. Michael Thaler. Journal of Economic Behavior & Organization, Volume 191, November 2021, Pages 501-518. https://doi.org/10.1016/j.jebo.2021.09.016

Highlights

• I experimentally study whether there are gender differences in motivated reasoning.

• I find that there are significant gender differences in motivated reasoning about performance on a knowledge task: men systematically motivatedly reason to think they outperformed others, while women do not.

• I also find that there are sizeable gender differences in overconfidence in the same direction as motivated reasoning.

• I find that gender differences in motivated reasoning is only observed on the question about performance, and that there are no differences in politically-motivated reasoning.

• Results suggest that men and women are both susceptible to motivated reasoning in general, but that only men find it particularly attractive to believe that they outperform others.

Abstract: Men and women systematically differ in their beliefs about their performance relative to others; in particular, men tend to be more overconfident. This paper provides support for one explanation for gender differences in overconfidence, performance-motivated reasoning, in which people distort how they process new information in ways that make them believe they outperformed others. Using a large online experiment, I find that male subjects distort information processing in ways that favor their performance, while female subjects do not systematically distort information processing in either direction. These statistically-significant gender differences in performance-motivated reasoning mimic gender differences in overconfidence; beliefs of male subjects are systematically overconfident, while beliefs of female subjects are well-calibrated on average. The experiment also includes political questions, and finds that politically-motivated reasoning is similar for both men and women. These results suggest that, while men and women are both susceptible to motivated reasoning in general, men find it particularly attractive to believe that they outperformed others.

Keywords: Motivated reasoningOverconfidenceGender differencesExperimental economics

JEL: J16D83C91D91

Three key ways people/organisms can differ in a trait: Mean averages (personality), how variable they are in trait intraindividually over time/context (predictability), & how reactive/responsive the trait is across differing ecologies/contexts (plasticity)

Unifying individual differences in personality, predictability and plasticity: A practical guide. Rose E. O'Dea, Daniel W. A. Noble, Shinichi Nakagawa. Methods in Ecology and Evolution, November 1 2021. https://doi.org/10.1111/2041-210X.13755

Abstract

Organisms use labile traits to respond to different conditions over short time-scales. When a population experiences the same conditions, we might expect all individuals to adjust their trait expression to the same, optimal, value, thereby minimising phenotypic variation. Instead, variation abounds. Individuals substantially differ not only from each other, but also from their former selves, with the expression of labile traits varying both predictably and unpredictably over time.

A powerful tool for studying the evolution of phenotypic variation in labile traits is the mixed model. Here, we review how mixed models are used to quantify individual differences in both means and variability, and their between-individual correlations. Individuals can differ in their average phenotypes (e.g. behavioural personalities), their variability (known as ‘predictability’ or intra-individual variability), and their plastic response to different contexts.

We provide detailed descriptions and resources for simultaneously modelling individual differences in averages, plasticity and predictability. Empiricists can use these methods to quantify how traits covary across individuals and test theoretical ideas about phenotypic integration. These methods can be extended to incorporate plastic changes in predictability (termed ‘stochastic malleability’).

Overall, we showcase the unfulfilled potential of existing statistical tools to test more holistic and nuanced questions about the evolution, function, and maintenance of phenotypic variation, for any trait that is repeatedly expressed.

Successful blinding is an important feature of double-blind randomized controlled trials, & ensures that the safety and efficacy of treatments are accurately appraised; but blinding is not successful among either patients or investigators

A systematic review and meta-analysis of the success of blinding in antidepressant RCTs. Amelia J Scott, Louise Sharpe, Ben Colagiuri. Psychiatry Research, November 24 2021, 114297. https://doi.org/10.1016/j.psychres.2021.114297

Highlights

• Successful blinding is an important feature of double-blind randomized controlled trials, and ensures that the safety and efficacy of treatments are accurately appraised.

• In a range of fields (e.g. chronic pain, general medicine), few trials report assessing the success of blinding.

• We do not know the frequency or success of blinding assessment among antidepressant RCTs within depression.

• Only 4.7% of RCTs examining antidepressants in depression assess blinding.

• Overall, blinding is not successful among either patients or investigators.

Abstract: Successful blinding in double-blind RCTs is crucial for minimizing bias, however studies rarely report information about blinding. Among RCTs for depression, the rates of testing and success of blinding is unknown. We conducted a systematic review and meta-analysis of the rates of testing, predictors, and success of blinding in RCTs of antidepressants for depression. Following systematic search, further information about blinding assessment was requested from corresponding authors of the included studies. We reported the frequency of blinding assessment across all RCTs, and conducted logistic regression analyses to assess predictors of blinding reporting. Participant and/or investigator guesses about treatment allocation were used to calculate Bang's Blinding Index (BI). The BI between RCT arms was compared using meta-analysis. Across the 295 included trials, only 4.7% of studies assessed blinding. Pharmaceutical company sponsorship predicted blinding assessment; unsponsored trials were more likely to assess blinding. Meta-analysis suggested that blinding was unsuccessful among participants and investigators. Results suggest that blinding is rarely assessed, and often fails, among RCTs of antidepressants. This is concerning considering controversy around the efficacy of antidepressant medication. Blinding should be routinely assessed and reported in RCTs of antidepressants, and trial outcomes should be considered in light of blinding success or failure.

Keywords: Randomized controlled trialsBlindingDepressionAntidepressants

Contra Duckworth and Seligman’s seminal work: Only intelligence predicted developmental changes in each measure of academic performance over time, self-control did not

Does Self-control Outdo IQ in Predicting Academic Performance? Alexander T. Vazsonyi, Magda Javakhishvili & Marek Blatny. Journal of Youth and Adolescence, Nov 20 2021. https://link.springer.com/article/10.1007/s10964-021-01539-4

Abstract: Duckworth and Seligman’s seminal work found that self-discipline (self-control) was more salient for academic achievement than intelligence. Very little replication work exists, including in different cultures; the current study addressed these gaps. Data were collected from 6th and 7th grade cohorts of early adolescents (N = 589; age: Mean = 12.34 years, and SD = 0.89; 58% female) over two years. The study tested whether self-control was a stronger predictor than intelligence in explaining academic performance two years later as well as in explaining developmental changes over the course of two years. Path analyses provided evidence that both self-control and intelligence longitudinally predicted teacher-reported academic competence as well as school-reported grades; however, intelligence was a significantly stronger predictor than self-control. In addition, only intelligence predicted developmental changes in each measure of academic performance over time, self-control did not.

Death reminders caused less negative affect and more positive affect than toothache reminders; & reactions to death were quite diverse and did not show signs of being dominated by existential anxiety

Storelv, Sina, and Bjørn Sætrevik. 2021. “Nothing Is Certain Except Taxes and the Other Thing: Searching for Death Anxiety in a Large Online Sample.” PsyArXiv. November 19. doi:10.31234/osf.io/3tkzq

Abstract: Philosophical and psychological literature has suggested that death anxiety has a profound impact on our lives, and is a fundamental aspect of what it means to be human. Based on such claims, we wanted to examine how people expressed their thoughts about death when giving short free-text responses in a large online sample. To do so we explored a qualitative dataset where 803 Americans state their thoughts about either death or physical pain (toothache). Comparing these, we found that death reminders caused less negative affect and more positive affect than toothache reminders. We also observed that reactions to death were quite diverse and did not show signs of being dominated by existential anxiety. Qualitative analyses indicate that psychological defense mechanisms do not seem to sufficiently explain the differences between the two conditions. The article also serves as a companion for the open dataset, to facilitate the exploration and reuse by other researchers.

 

The smaller preferences for sexually dimorphic facial cues in older adults compared to young adults suggest that older adults may shift away from mating-oriented psychology as they become less fertile

The Autumn Years: Age Differences in Preferences for Sexually Dimorphic Faces. Chengyang Han, Xiangqian Li, Xiyue Chen, Xue Lei, Chuanjing Liao, Lingshan Zhang, Bingxin Li, Xian Peng & Edward R. Morrison. Archives of Sexual Behavior, Nov 17 2021. https://link.springer.com/article/10.1007/s10508-021-02168-5

Abstract: Life history theory proposes that it is adaptive for older people to shift investment away from reproductive effort (such as mating) to survivorship. However, it remains unclear whether the shift is also present at the psychological level. We investigated this question by comparing preferences for mate choice-relevant cues, sexually dimorphic facial images, between older (60 years and older, n = 92) and younger adults (18–40 years, n = 86). Results showed that older adults had significantly smaller preferences for sexually dimorphic faces of both sexes than young adults. Specifically, both older men and women showed no significant preferences for sexually dimorphic traits when judging opposite-sex faces, and smaller preferences for masculine male faces and feminine female faces when judging same-sex faces. Young adults generally showed strong preferences for masculine male faces and feminine female faces. In Study 2, we confirmed that the absent/reduced preferences in older adults for sexually dimorphic faces did not result from poor visual ability. The smaller preferences for sexually dimorphic facial cues in older adults compared to young adults suggest that older adults may shift away from mating-oriented psychology as they become less fertile.

Consistent low-to-moderate alcohol consumption in early-to-middle adulthood predicted lower depressive symptoms at age 50; his work offers preliminary evidence that such protective effects may be causal

Visontay, Rachel, Louise Mewton, Tim Slade, Izzuddin M. Aris, and Matthew Sunderland. 2021. “Moderate Alcohol Consumption and Depressive Symptoms: A Marginal Structural Model Approach Promoting Causal Inference.” OSF Preprints. November 19. doi:10.31219/osf.io/e2gcm

Abstract

Importance: Prevention of depressive symptoms and disorders is a key public health priority but requires an improved understanding of modifiable risk and protective factors. A salient unanswered question in this context is whether the apparent protective effect of alcohol against depression may be causal.

Objective: To compare the effects of consistent abstinence, occasional, moderate, and heavy alcohol consumption throughout early-to-middle adulthood on depressive symptoms at age 50.

Design: This secondary analysis of the National Longitudinal Survey of Youth (NLSY79) cohort employed a marginal structural model approach in assessing the relationship between alcohol consumption in early-to-middle adulthood (29-37 through 41-49) and depressive symptoms at age 50. Alcohol consumption was based on measurements at 1994, 2002, and 2006, covariates at 1992, 1994, and age 40 (1998-2006), and outcome at age 50 (2008-2016).

Setting: The NLSY79 is a nationally representative, population-based cohort study.

Participants: 5,667 eligible participants at baseline provided valid data on alcohol consumption, depressive symptoms, and covariates of interest.

Exposure: Alcohol consumption was categorised as either abstinence, occasional, moderate, or heavy drinking in 1994, 2002, and 2006.

Main Outcome and Measure: Depressive symptoms at age 50 as measured by the Centre for Epidemiological Studies-Depression Scale short form (CES-D-SF).

Results: Of the 5,667 eligible participants at baseline, 2,862 [50.50%] were female and the mean age was 30.81 [2.24], with 3,593 participants providing valid outcome data for analysis. Results of linear contrasts from marginal structural models were consistent with a J-shaped relationship, where both consistent occasional (b=-0.84, CI= -1.47, -.11) and consistent moderate (b=-1.08, CI=-1.88, -.20) drinkers had significantly reduced predicted CES-D-SF scores at age 50 compared to consistent abstainers. Consistent heavy drinkers were predicted to have increased depressive symptoms, but this was not statistically significant (b=0.34, CI=-0.62, 1.25). In sex-stratified analyses, results were similar for females and males.

Conclusions and Relevance: In this secondary analysis of longitudinal data accounting for time-varying exposure and confounding, consistent low-to-moderate alcohol consumption in early-to-middle adulthood predicted lower depressive symptoms at age 50, compared with those abstaining from alcohol. This work offers preliminary evidence that such protective effects may be causal.

Rolf Degen summarizing... Comic book bodies are supernormal stimuli that cater to the unrealistic sexual imagination of a predominantly male audience

Burch, R. L., & Widman, D. R. (2021). Comic book bodies are supernormal stimuli: Comparison of DC, Marvel, and actual humans. Evolutionary Behavioral Sciences, Nov 2021. https://doi.org/10.1037/ebs0000280

Abstract: This study expanded upon Burch and Johnsen’s (2020) work on exaggerated bodies in Marvel comic book characters by also examining DC characters and actual humans. Compared to Marvel, DC men were not significantly taller but were significantly thinner and had significantly smaller shoulder to waist ratios. DC women were almost identical to Marvel women in height and weight, but DC women had smaller waist to hip ratios, making them curvier. Comic book bodies were then compared to actual humans; champion male bodybuilders, most frequently searched women on 1 of the most popular pornography websites, and a nationally representative U.S. sample. DC men had shoulder to waist ratios on par with champion bodybuilders while Marvel exceeded them. Both DC and Marvel women had lower waist to hip ratios than the Internet pornography sample. The average U.S. woman’s WHR was similar to the maximum WHR for the comic book and pornography sample, and the minimum U.S. woman’s WHR was similar to the average WHR for those samples. These findings support Burch and Johnsen (2020) and provide a better picture of how comic book depictions are hypersexualized supernormal stimuli.

Our review of the malevolent creative processes suggest that we have unintentionally avoided uncomfortable truths around who is capable of generating & instantiating malevolent ideas

Malevolent Creativity and Malevolent Innovation: A Critical but Tenuous Linkage. Samuel T. Hunter, Kayla Walters, Tin Nguyen, Caroline Manning & Scarlett Miller. Creativity Research Journal, Nov 21 2021. https://doi.org/10.1080/10400419.2021.1987735

Abstract: Interest is growing in the dark side of creativity and recent research has been instrumental in improving our understanding of the phenomenon. However, such efforts have also revealed confusion regarding the definition and operationalization of the dark side of creativity and malevolent creativity in particular. In response, we offer definitional clarity for both the generation of novel, malevolent ideas (i.e., malevolent creativity) as well as the implementation of those ideas (i.e., malevolent innovation). In addition, we present a framework outlining how and why malevolent ideas transition from ideation to implementation. This framework considers influences linked to both ability and willingness to engage in malevolent processes, spanning intrapersonal and interpersonal factors. Our review reveals a complex but tenuous link between malevolent creativity and innovation and one that requires consideration of the processes connecting the two. Moreover, our review of the malevolent creative processes suggest that we have unintentionally avoided uncomfortable truths around who is capable of generating and instantiating malevolent ideas. Implications and a plan for moving research forward are discussed.

---

From the Encyclopedia of Creativity, 3rd ed, p 177.

Malevolent Creativity

Creativity is often beneficial, however, people also generate novel ways to harm and hurt (Baas et al., 2019). Examples of malevolent creativity include data fabrication of scientists, dirty tricks in political campaigns and firms falsifying information. Provocative and threatening circumstances trigger malevolent creativity (Baas et al., 2019), so it is likely that competition increases creative malevolent responses.

Anecdotes support this notion. For example, to compete with Virgin Atlantic, British Airways resorted to dirty tricks, which included circulating rumors that Virgin CEO Richard Branson had HIV and telling Virgin’s customers that their flights had been canceled. In addition, the fierce competition in science leads some scientists to perform biased peer review, sabotage competitors, and engage in questionable research practices.

There is also empirical support that competition breeds malevolent creativity. In studies conducted in our lab, people who were engaged in a competitive game against another person came up with more malevolent uses for a brick (e.g., using a brick as a weapon, or to sink a body) than non-competing others (see e.g., Baas et al., 2019). Together, these findings suggest that competition may also fuel a much darker side of creativity by facilitating the generation of ideas that are malevolent in nature.

Financial crises and political radicalization: How failing banks paved Hitler's path to power, and to more pogroms and deportations in the most affected areas

Financial crises and political radicalization: How failing banks paved Hitler's path to power. Sebastian Doerr, Stefan Gissler, Jose-Luis Peydro and Hans-Joachim Voth. BIS Working Papers No 978, November 22 2021. https://www.bis.org/publ/work978.htm

Summary

Focus: Do financial crises fan the flames of fanaticism? Many have argued that the financial crisis of 2007–09 not only wrought havoc on employment and output but that its problematic aftermath of failing financial institutions, public bailouts and austerity may also have paved the way for populists around the world. We examine the canonical case of a radical movement's rise to power: Hitler's Nazi party, which took office in the wake of the severe 1931 banking crisis in Germany – a turning point in modern history.

Contribution: Several cross-country studies have concluded that a link exists between financial crises and right-wing populist movements. What is still missing are studies demonstrating that a financial shock can lead to a broad-based radicalisation of the electorate, with major political consequences. It has also remained unclear how economic and financial shocks interact with cultural identity in the turn toward radicalisation.

Findings: Using newly collected data on the exposure of individual cities to the failure of Danatbank – the bank at the heart of Germany's 1931 financial crisis – we show that a financial shock led to a generalised radicalisation of the electorate. This directly helped the Nazi party to gain power. Importantly, we demonstrate that the financial shock interacted with pre-existing cultural attitudes: the surge in support for the Nazis in response to the shock was greatest in places with a previous history of antisemitism. Voters were radicalised both at the ballot box and in their actions. Once the Nazis were in power, both pogroms and deportations were more likely to occur in places worse affected by the banking crisis.

Abstract: Do financial crises radicalize voters? We study Germany's 1931 banking crisis, collecting new data on bank branches and firm-bank connections. Exploiting cross- sectional variation in pre-crisis exposure to the bank at the center of the crisis, we show that Nazi votes surged in locations more affected by its failure. Radicalization in response to the shock was exacerbated in cities with a history of anti- Semitism. After the Nazis seized power, both pogroms and deportations were more frequent in places affected by the banking crisis. Our results suggest an important synergy between financial distress and cultural predispositions, with far-reaching consequences.

Keywords: financial crisis, political extremism, populism, anti-Semitism, culture, Great Depression.

JEL classification: E44, G01, G21, N20, P16.

Sniffing the human body volatile hexadecanal blocks aggression in men but triggers aggression in women; our results imply that sniffing babies may increase aggression in mothers but decrease aggression in fathers

Sniffing the human body volatile hexadecanal blocks aggression in men but triggers aggression in women. Eva Mishor et al. Science Advances, Vol 7, Issue 47. Nov 19 2021. DOI: 10.1126/sciadv.abg1530

Abstract: In terrestrial mammals, body volatiles can effectively trigger or block conspecific aggression. Here, we tested whether hexadecanal (HEX), a human body volatile implicated as a mammalian-wide social chemosignal, affects human aggression. Using validated behavioral paradigms, we observed a marked dissociation: Sniffing HEX blocked aggression in men but triggered aggression in women. Next, using functional brain imaging, we uncovered a pattern of brain activity mirroring behavior: In both men and women, HEX increased activity in the left angular gyrus, an area implicated in perception of social cues. HEX then modulated functional connectivity between the angular gyrus and a brain network implicated in social appraisal (temporal pole) and aggressive execution (amygdala and orbitofrontal cortex) in a sex-dependent manner consistent with behavior: increasing connectivity in men but decreasing connectivity in women. These findings implicate sex-specific social chemosignaling at the mechanistic heart of human aggressive behavior.

Discussion

Impulsive aggression is a major factor in the human condition, yet how exactly aggression is triggered or blocked in the human brain remains unclear (11, 12). Moreover, real-world human impulsive aggression is one of the most sexually dimorphic behaviors (40), yet what brain mechanisms underlie this dimorphism also remains unclear (12). In animals ranging from insects to rodents, aggression is sexually dimorphic at levels ranging from genes to cells, and this dimorphism in aggression has been linked to dimorphism in the olfactory system (41). Here, we find the same in humans. We observed that sniffing a body volatile, namely, HEX, significantly decreased aggression in men yet significantly increased aggression in women. In both men and women, HEX increased brain activity in the AG, a cross-modal integrating hub involved in social cognition (42). In other words, in humans, like in rodents, a “social odor” activates the “social brain.” Moreover, HEX modulated functional connectivity between these substrates of social appraisal (AG) and a network previously associated with aggression. This included modulation of functional connectivity with the temporal pole (TP), an area similarly implicated in social appraisal (43) and aggression (44), and modulation of functional connectivity with the amygdala and OFC, namely, substrates implicated in aggressive execution (10, 12). All this modulation occurred in a sex-dependent manner consistent with behavior: HEX increased connectivity in men but decreased it in women. Thus, HEX may lead to increased or decreased aggression through increased or decreased control by the AG over the amygdala through a circuit involving the TP and OFC. This modulation of social behavior through modulation of functional brain connectivity was similarly observed following intranasal administration of oxytocin, which reduced OFC connectivity with the amygdala, and in this may have reduced negative emotional arousal (45). This further points to what may be considered a physiological counterpart of this brain mechanism: As stress increases, men become more aggressive and women become less aggressive (46). As stress decreases, men become less aggressive and women become more aggressive (47). In this manner, a non–sex-specific effect of HEX on the stress response (always reducing stress) may evolve into a sex-specific effect of HEX on aggression (increased aggression in women yet decreased aggression in men).

The above detailed neuroanatomy and mechanism may underlie a direct circuit from reception to action without the mediation of conscious perception. This echoes rodent circuitry, where OR37B projections bypass the olfactory cortex and connect directly to the paraventricular nucleus of the hypothalamus, where HEX reduces activity in corticotrophin-releasing cells, thus reducing activation of the hypothalamus-pituitary-adrenal axis (16). Although we cannot trace connectivity of a single olfactory receptor subtype in humans, it is tempting to liken the downstream activation in the absence of olfactory cortex activation we observed in response to HEX to the circuit detailed in rodents.

The sex dimorphism in our behavioral and brain results dovetails with previous findings obtained using functional brain imaging (48) and EEG (15) to depict a level of functional brain sex dimorphism in response to social odors that is not matched by any other sensory stimulus that we are aware of. Human functional brain responses to basic auditory and visual cues are generally nondissociable by sex (49), yet here, we could use them alone to discriminate men from women at 79.6% accuracy. This begs the question: what behavioral setting could underlie selection for a body volatile that increases aggression in women but decreases it in men? Or in other words, what could be the ecological relevance of these results? In this respect, we call attention to the setting of infant rearing. Parents across cultures are encouraged to sniff their babies (50), an action that activates brain reward circuits in women (51). Our results imply that sniffing babies may increase aggression in mothers but decrease aggression in fathers. Whereas maternal aggression has a direct positive impact on offspring survival in the animal world (52), paternal aggression has a negative impact on offspring survival (53). This is because maternal aggression (also termed maternal defense behavior) is typically directed at intruders, yet paternal aggression, and more so nonpaternal male aggression, is often directed at the offspring themselves (54, 55). If babies had a mechanism at their disposal that increased aggression in women but decreased it in men, this would likely increase their survival. With the hypothesis in mind that HEX provides babies with exactly such a mechanism, we first note that infant rearing is the one social setting where humans have extensive exposure to conspecific feces, a rich source of HEX (22). We also turned to a recently published analysis of baby-head volatiles (56), yet in contrast to our hypothesis, this report did not mention HEX. We turned to the authors of that report, who explained that the published analysis was not tuned to the near semivolatile range of HEX. With our question in mind, they (now coauthors T.U. and M.O.) sampled an additional 19 babies (fig. S10A), using gas chromatography (GC) × GC–mass spectrometry, and observed that HEX is one of the most abundant baby-head volatiles, evident in 17 of the 19 babies (fig. S10, B and C). Moreover, they also searched for the two additional known ligands of OR37, namely, pentadecanal and heptadecanal, and found both, albeit at levels much lower than HEX. Pentadecanal was evident in 15 babies but only at an average peak area of 56% that of HEX, and heptadecanal was evident in 16 babies but only at average peak area of 45.5% that of HEX (HEX greater than pentadecanal and peptadecanal: Kruskal-Wallis χ2 = 7.65, df = 2, P = 0.02) (fig. S10C). This outcome renders our overall ecological hypothesis plausible and retrospectively supports our selection of HEX as a testing target. In summary, babies emit HEX from their head. This is expected to trigger aggression in women but block aggression in men, and both of these impacts are expected to increase baby survival.

Given all the above, should we label HEX as a human pheromone? Sniffing human bodily secretions such as sweat and tears drives assorted behavioral and physiological effects (7, 24), and body odors may reflect assorted emotional states (57), including aggression (13, 14), but the identity of specific molecular components involved in human social chemosignaling has remained elusive (58). Moreover, the current view on human social chemosignals is that, to the extent that they exist, they likely entail alterations in the ratios of components in complex body odor bouquets and not single molecular species (59). Yet, here, we identify one component, namely, HEX, whose effects can be seen as consistent with those of a mammalian pheromone (60). Previously, the steroidal molecules estratetraenol (EST) and androstadienone (AND) had been proposed as human pheromones, yet this labeling was often rejected, primarily because EST and AND do not clearly trigger or block behavior, nor do they have obvious ecological relevance (59, 61). Here, HEX had a pronounced effect on behavior and, moreover, on the behavior of aggression, a domain dominated by pheromonal communication in most mammals (3). The notion of pheromonal communication was once considered dependent on a functional vomeronasal system, a system that humans may not have (62). More recent views, however, blur this distinction and highlight pheromonal communication through the main olfactory system as well (63–65). Given all this, we think that had we presented an equivalent set of results obtained from mice, very few would argue the pheromone label. In turn, if HEX is a human pheromone, is it a cuing pheromone that is emitted consistently by the sender or a signaling pheromone that is emitted only during appropriate behavioral context (61)? Here, we reach at the primary limitation of this study: Although we think of HEX as a signal, we did not measure its emission as a function of behavior. Had we measured HEX emission under different conditions and found that its emission increased under the endurance of aggression, this would have closed the loop of a signaling pheromone. Such an effort, however, was far beyond the scope of the current study and remains the key missing component for labeling HEX a human signaling pheromone.

Beyond this, we would like to acknowledge several additional limitations in this study: First, although we used various control conditions across experiments (eugenol, mineral oil, and blank air), we did not test any other potential OR37 ligands. The rationale for selecting HEX was detailed in Introduction, but future testing of additional potential ligands remains an important question. Second, we do not know whether the concentrations of HEX that we used were physiological. This is because we do not know the concentrations that humans emit (the existing reports are relative), and we do not know the concentration that actually reached our participants using the current paradigms (e.g., experiment 1 sniff-jar versus experiment 2 olfactometer). Third, regarding our imaging results, we reiterate that correlation is not causation. We identify a brain pattern associated with HEX, and it is tempting to suggest that this pattern is responsible for the observed effects, yet this can only be proven by experiments where the brain mechanism is perturbed, experiments that are very difficult to conduct in human participants. Last, we also acknowledge that our suggested ecological relevance in infant rearing was not directly tested in this study. One may note that there are various forms of aggression, and whereas our tasks measured interpersonal aggression, our infant-rearing hypothesis alludes to paternal/maternal aggression. Thus, although we think it is a plausible hypothesis, it remains to be experimentally verified, and here serves only as an example of possible ecological relevance for our results.

Despite the above limitations, we conclude in stating that sniffing the body odor constituent HEX blocks aggression in men but triggers aggression in women. HEX may exert its effects by modulating functional connectivity between the brain substrates of social appraisal and the brain substrates of aggressive execution. This places chemosignaling at the mechanistic heart of human aggression and poses but one added example to the rapidly growing body of evidence implicating social chemosignaling as a major, albeit mostly subconscious, power in human behavior.