Cross‐sex shifts in two brain imaging phenotypes and their relation to polygenic scores for same‐sex sexual behavior: A study of 18,645 individuals from the UK Biobank

Cross‐sex shifts in two brain imaging phenotypes and their relation to polygenic scores for same‐sex sexual behavior: A study of 18,645 individuals from the UK Biobank. Christoph Abé  Alexander Lebedev  Ruyue Zhang  Lina Jonsson  Sarah E. Bergen  Martin Ingvar  Mikael Landén  Qazi Rahman. Human Brain Mapping, February 26 2021. https://doi.org/10.1002/hbm.25370

Abstract: Genetic and hormonal factors have been suggested to influence human sexual orientation. Previous studied proposed brain differences related to sexual orientation and that these follow cross‐sex shifted patterns. However, the neurobiological correlates of sexual orientation and how genetic factors relate to brain structural variation remains largely unexplored. Using the largest neuroimaging‐genetics dataset available on same‐sex sexual behavior (SSB) (n = 18,645), we employed a data‐driven multivariate classification algorithm (PLS) on magnetic resonance imaging data from two imaging modalities to extract brain covariance patterns related to sex. Through analyses of latent variables, we tested for SSB‐related cross‐sex shifts in such patterns. Using genotype data, polygenic scores reflecting the genetic predisposition for SSB were computed and tested for associations with neuroimaging outcomes. Patterns important for classifying between males and females were less pronounced in non‐heterosexuals. Predominantly in non‐heterosexual females, multivariate brain patterns as represented by latent variables were shifted toward the opposite sex. Complementary univariate analyses revealed region specific SSB‐related differences in both males and females. Polygenic scores for SSB were associated with volume of lateral occipital and temporo‐occipital cortices. The present large‐scale study demonstrates multivariate neuroanatomical correlates of SSB, and tentatively suggests that genetic factors related to SSB may contribute to structural variation in certain brain structures. These findings support a neurobiological basis to the differences in human sexuality.

4 DISCUSSION

In this large‐scale study on SSB, we used brain imaging phenotypes from two imaging modalities and a multivariate classification algorithm to extract independent brain covariance patterns related to sex. We then tested for SSB related cross‐sex shifts in such patterns. For the first time, we also examined whether polygenic scores for SSB relate to brain imaging phenotypes.

Our results showed that the PLS classifier was effective in classifying males and females, and that patterns important for classification were less pronounced in non‐heterosexual individuals, indicative of a cross‐sex shift. The analysis of LVs demonstrated that one (LV1) displayed a sex‐by‐SSB interaction. This interaction remained following adjustment for potential confounding variables, including psychiatric diagnoses and victimization experiences, and was driven by the fact that nHeF showed larger LV1 scores than HeF. Since males showed the largest LV scores, this indicates an SSB‐related cross‐sex shift in multivariate brain patterns predominantly in females. This shift in LV1 was not observed in males, which could potentially arise because SSB‐related differences in males might have less of a covarying nature, regionally differ, be more focal, or less pronounced (smaller effect size) compared to females, as indicated by secondary univariate analyses (Figure 6). However, these differences could also be explained by the fact that the SSB measure does not capture all aspects of sexual orientation. While SSB correlates highly with other components of sexual orientation, nHeF and nHeM in our sample may differ in other components such as sexual attractions, sexual identity labels, or romantic attractions (J. M. Bailey et al., 2016). Hence, we cannot exclude the presence of sub‐groups among non‐heterosexual individuals. In line with that notion, in an explorative analysis excluding individuals with one or two reported lifetime same‐sex partners (see Supporting Information), the peak of the LV1 distribution in nHeM was shifted toward smaller values (the mean of females), indicating that a sub‐group of nHeM (e.g., those with more same‐sex partners) may show a more female‐like multivariate brain pattern. However, this effect requires further investigation. Nevertheless, our findings suggest sexuality‐related variation in multivariate brain data, supporting the utility of data‐driven classification and that multivariate pattern analyses are effective at identifying such associations on group level, at least in females.

Our neuroanatomical findings support a number of previous small‐scale reports of sexual orientation‐related differences (Abé et al., 2014; Abé et al., 2018; Manzouri & Savic, 2018a, 2018b; Ponseti et al., 2007; Savic & Lindström, 2008) in that they indicate SSB‐related cross‐sex shifts in brain imaging phenotypes. Intriguingly, the calcarine sulcus (part of the visual cortex) appears to be the most consistently reported structure showing sexual orientation‐related differences (Abé et al., 2014; Abé et al., 2018; Manzouri & Savic, 2018b), which is consistent with results from our secondary univariate analyses (ROI approach: Figure 6, and whole brain analysis: Data S2). We did not replicate sexual orientation differences in the anterior cingulate cortex (Manzouri & Savic, 2018a, 2018b) and hippocampus (Abé et al., 2014) in males. Cross‐sex shifts in brain data are also consistent with a large body of empirical findings demonstrating cross‐sex shifted patterns of gender‐related behavior, cognitive ability (in tasks that typically differ between the sexes), and certain personality traits (Allen & Robson, 2020; Bailey et al., 2016; Li et al., 2017; Rieger et al., 2008; Xu et al., 2017). However, there is considerable overlap in the distribution of LV‐scores between the groups, and the magnitude of the effects for SSB‐related brain differences seem smaller than those reported for the aforementioned behavioral traits. Notably, effect sizes for SSB‐related differences in cortical volumes were also smaller than those of sex differences (Table S3, Data S2).

The imaging variables that loaded most strongly on LV1 (displaying the sex‐by‐SSB interaction) were measures of regional volumes in prefrontal, parietal, and occipital (including visual) cortices. In the context of SSB, the visual cortex is involved in visual perception and processing of sexual stimuli (Georgiadis & Kringelbach, 2012). Prefrontal areas are involved in the integration of sensory information and reward‐value representation of sexual stimuli (Georgiadis & Kringelbach, 2012). Together with the precuneus, involved in self‐referential processes (Cavanna & Trimble, 2006), these areas are also recruited during visuo‐spatial processing and selective visual attention (Cavanna & Trimble, 2006; Georgiadis & Kringelbach, 2012; Paneri & Gregoriou, 2017; Posner & Gilbert, 1999). However, this study does not allow conclusions about causality or the brain regions' functional involvement. It requires further testing how differences in brain structure relate to SSB. Note that although volumes of those brain regions that tended to successfully predict group membership largely overlap with those previously reported in other studies, in contrast to direct group comparisons in univariate analyses, PLS results should not necessarily be interpreted as evidence of structural differences between the groups, but rather as generalized covariance patterns in the brain data that discriminate between them. Another important finding is that while LV1 appeared to capture the hypothesized cross‐sex shift, LV2 appeared to capture a main effect of SSB. This may indicate that SSB‐related multivariate brain patterns may exist that do not follow a cross‐sex shift and are similar in both nHeM and nHeF (regardless of sex). It is also noteworthy that cortical volumetric measures showed the highest loadings, whereas those of subcortical structures and DTI‐based FA values were close to zero, indicating that sex‐related brain phenotype variation may be more pronounced in gray matter than white matter or subcortical measures.

The causes of sexual orientation‐related differences in brain structure are as yet unknown. Both genetic and non‐genetic factors have been proposed to play a role, with the most prominent hypothesis involving prenatal androgen influences (Bailey et al., 2016; Kevin, Khytam, & David, 2018). Genetic influences are modest based on existing twin models and molecular genetic studies (Bailey et al., 2000; Bailey et al., 2016; Ganna & Verweij, 2019; Langstrom et al., 2010) and are almost certainly polygenic in nature (Ganna & Verweij, 2019). Here, we investigated genetic influences on brain phenotypes by testing the associations between polygenic scores for SSB (PS‐SSB) and brain imaging phenotypes. Whereas PS‐SSB did not seem to predict multivariate brain patterns (LVs), we found that PS‐SSB was associated with cortical volumes in individual brain regions. These associations were observed mainly in lateral occipital and temporo‐occipital cortex. In lateral occipital cortex, higher PS‐SSB was associated with lower volumes in both males and females. In temporo‐occipital cortex, higher PS‐SSB was associated with lower cortical volumes in nHeM and larger volumes nHeF. These findings tentatively indicate that genetic factors related to SSB are associated with variation in some cortical structures and that a higher genetic predisposition to SSB has the opposite effect on cortical volume in males and females who reported SSB. These associations were small and PS‐SSB explained little of the variance in brain structure. Notably, we did not find significant genetic correlations in complementary analyses linking previously published SSB and brain phenotype GWASs (Elliott et al., 2018; Ganna & Verweij, 2019). Therefore, these genetic associations should be treated with caution, and additional factors are likely to explain brain variation associated with human sexuality. Mechanisms responsible for how genetic factors influence brain structure, function, and in turn behavior are complex and multi‐factorial. Given the general limitations of the applied methodology (see below), these cannot be derived from this study. We also want to note that, given the wide and overlapping range of LVs and PS‐SSB, as well as the weak classification performance when solely predicting SSB (AUC = 0.57), the present results cannot be used to predict an individual's sexual orientation based on genetic or neuroimaging data.

Understanding the appeal of libertarianism: Gender and race differences in the endorsement of libertarian principles

Understanding the appeal of libertarianism: Gender and race differences in the endorsement of libertarian principles. Mary‐Kate Lizotte  Thomas Warren. Analyses of Social Issues and Public Policy, February 26 2021. https://doi.org/10.1111/asap.12237

Abstract: There is a stereotype of libertarians being young, college educated, white men and that the Libertarian Party lacks appeal among women and individuals of color. There is a great deal of research investigating gender differences in public opinion on a number of issues including the provision of government resources and government spending (Barnes and Cassese; Howell and Day). Nevertheless, there is no work specifically investigating why women and nonwhites do not find libertarianism appealing. We test several hypotheses using 2016 American National Election Study data and 2013 PRRI data. We find a sizeable and significant gender gap and race gap in support for libertarian principles. We investigate several explanations for these gaps finding moderate support for self‐interest, racial attitudes, and egalitarianism as reasons for women and African Americans being less supportive of Libertarian Principles. We believe that the modest success of and media attention garnered by Ron Paul and Rand Paul in recent years along with the success of the Libertarian Party presidential ticket in 2016 highlights the need to understand who is drawn to libertarianism and why.

Males were the most eager to view sexually arousing images of the opposite sex, whereas females were more strongly motivated to view less sexual images of couples

Sex Differences in the Motivation for Viewing Sexually Arousing Images. Maiko Kobayashi, Koyo Nakamura & Katsumi Watanabe. Evolutionary Psychological Science, Feb 27 2021. https://rd.springer.com/article/10.1007/s40806-021-00276-y

Abstract: Sexual motivation strongly influences mate choice and dating behavior and can be triggered by merely viewing sexually arousing visual images, such as erotic pictures and movies. Previous studies suggested that men, more than women, tend to search for sexual cues that signal promiscuity in short-term mates. However, it remains to be tested whether sex differences in the motivation to view sexual cues can be observed by using robust and well-controlled behavioral measures. To this end, we employed a pay-per-view key-pressing task. Japanese self-identified heterosexual male and female participants viewed images of men, women, or couples with two levels of sexual arousal (sexual vs. less sexual). Participants could alter the viewing time of a presented image according to their willingness to keep viewing it. Male participants were the most eager to view sexually arousing images of the opposite sex, whereas female participants were more strongly motivated to view less sexual images of couples. Such sex differences may reflect differentiated reproductive strategies between men and women in terms of men’s motivation toward promiscuity and women’s motivation toward long-term relationships.

Discussion

The purpose of this study was to examine whether there are differences between men and women in terms of their motivation to view sexual images. Drawing on SST (Buss & Schmitt, 1993), we hypothesized that our self-identified heterosexual male and female participants would view the opposite-sex images longer than the same-sex images because opposite-sex images can evoke sexual arousal (Chivers & Bailey, 2005; Hahn et al., 2013), and that men would be more eager than women to view the highly sexual images because sexually explicit opposite-sex images suggest sexual accessibility (Buss & Schmitt, 1993). Our results indicate that the motivational salience of sexual images differed between male and female participants. Here, we summarize the main findings and interpret such differences in light of the SST (Buss & Schmitt, 1993).

First, as predicted, our male participants viewed the opposite sex images and couple images longer than the same sex images, irrespective of the sexual arousal of the images. These results confirm that heterosexual males are strongly motivated to view opposite sex images (Baumeister et al., 2001; Hamann et al., 2004). Furthermore, the number of key-presses by the male participants for the opposite sex images in the sexual condition was higher compared to that for the other image. Such prioritized motivational responses to the opposite sex images were also evident in likability and sexual arousal ratings. In the less sexual condition of the opposite-sex images, there were no significant differences in the pay-per-view key pressing, but there were significant differences in subjective likeability and arousal ratings. This result was not reflected in the behavior of opposite sex images with less sexual condition, even though male participants reported higher levels of subjective sexual arousal and preference than female participants. This suggests that the pay-per-view responses reflect sexual motivation to view the images, not merely the subjective evaluations of them (Aharon et al., 2001). These observations of the male participants’ behavior are consistent with the behavioral predictions provided by the SST (i.e., prediction 6: cues to immediately available sex will be valued by men in short-term mates more than in long-term mates because they provide cues to sexual accessibility). Previous studies also suggest that men are likely to prefer visual sexual cues than women, and are thus eager to view nude images of women (Baumeister et al., 2001; Regnerus et al., 2016). Also, recent studies reveal that heterosexual men prefer to view opposite-sex images in both erotic and non-erotic contexts more than heterosexual women do (Lykins et al., 2006; Lykins et al., 2008; Rupp & Wallen, 2007). Taken together, these findings suggest that men tend to value cues to immediately available sex (e.g., promiscuity) in short-term mates (Buss & Schmitt, 1993), possibly leading to men’s greater attraction to sexually arousing visual images (Symons, 1979). Our results support these previous findings by using a behavioral measurement that reflects sexual motivation.

In contrast to the male participants, the female participants displayed different patterns of pay-per-view responses depending on the sexual arousal of the images. From the standpoint of mate choice, the female participants would have also viewed the male images longer than the female images (Chivers & Bailey, 2005; Hahn et al., 2013). However, the female participants in this experiment viewed the couple images longer than the other images, while they decreased the viewing time for all types of images in the sexual condition. Female participants in this study were less responsive than male participants to opposite sex images in all pay-per view key-pressing, subjective likeability and arousal. Previous studies indicate that women react to men’s physical attractiveness as strongly as men react to women’s physical attractiveness (Hahn et al., 2013; Hamann et al., 2004; Wiederman & Dubois, 1998). This indicates that men and women are equally able to identify sexual cues from the opposite sex (Kowalski, 1993). It is noteworthy that many previous findings were based on participants from Western cultures; so, the inconsistency between previous findings and our results may be partially derived from cultural and social differences in sexual attitudes (Thomas et al., 2015). Our results that women decreased viewing time for both sexual and less sexual same sex images ostensibly seem to be inconsistent with some previous findings (e.g., Women react to men’s physical attractiveness as strongly as men react to women’s physical attractiveness (Hahn et al., 2013; Hamann et al., 2004; Wiederman & Dubois, 1998). One possible explanation for the inconsistent results can be provided by cultural differences in expression and social expectations of female sexuality. Indeed, Western women tend to explicitly report higher sexual desire, arousal, and pleasure when experiencing orgasm compared to East Asian women (Brotto et al., 2005; Cain et al., 2003). Also, East Asian women are likely to have automatic thoughts related to sexual guilt (e.g., “I am an immoral person for wanting sex,” or “It is wrong for a woman to initiate sexual activity?”), which may originate from implicit social expectations of female sexuality and thereby motivate them to avoid sexual scenarios they believe immoral (Woo et al., 2011). Although such cultural differences are also found in men, they are reflected in women more strongly (Abramson & Imai-Marquez, 1982). It would be interesting to address this question by conducting a cross-cultural study with East-Asian and Western populations.

Of particular interest is that our female participants viewed the couple images longer than the male and female images in the less sexual condition. Such patterns were also observed in the subjective likeability rating task but not in the subjective arousal task. These results are consistent with previous findings that women are highly motivated to view couple images depicting relationship contexts and emotional bonds (Laan et al., 1994; Carvalgho,  2013). According to the behavioral prediction of the sexual strategies theory, women place more emphasis on romantic relationships than men’s physical attractiveness (Rupp & Wallen, 2007). Indeed, Dewitte (2015) showed that women feel greater sexual desire when primed with visual cues conjuring up romantic relationships. Correspondingly, women experience more intense sexual arousal when viewing pornography with romantic elements (e.g., glancing at each other, kissing, or marriage) than pornography with actual sexual intercourse (Laan et al., 1994). In our study, the female participants displayed prolonged viewing of less sexual couple images compared to the highly sexual couple images. The less sexual couple images often include romantic elements as described above. The female preference for romantic or relational elements likely derives from psychological adaptations for long-term relationship and pair-bonding signals (Buss & Schmitt, 1993; Chivers & Timmers, 2012). Long-term relationships are more advantageous for women than for men (Trivers, 1972), because women tend to be the more heavily investing sex (e.g., fertilization, gestation, placentation, and maternal care). Thus, women’s strong preference for long-term mating cues might reflect the motivation to secure the quantity and quality of external resources for themselves and their offspring from men (Buss & Schmitt, 1993). At the same time, our female participants made key-press responses to reduce the viewing time for images with high sexual arousal (sexual condition), regardless of the image category. This response pattern may be related to an adaptive behavior such as preventing the initiation of sexual intercourse after only brief intervals of time (Buss & Schmitt, 1993) and/or women’s sexual attitudes are influenced by societal norms that place them in a dilemma regarding sexuality, such that female sexuality has historically been suppressed and deemed as immoral (Lemer et al., 2013).

The present study has been based on the sexual strategies theory and has discussed considerations related to reproductive success, such as opposite-sex and couple images, but it is necessary to discuss the results for same-sex sexual images, which are not thought to contribute to reproduction according to the sexual strategies theories. Our female participants were more motivated, more preferred, and more aroused by the same sex images with less sexual condition than male participants. This result may be due to a greater intra-individual variation in female preferences, behavior, attitudes, and responsiveness to cultural influences drives. Greater flexibility in female sexual preferences may also be reflected in a less specific pattern of sexual arousal (Baumeister et al., 2001; Chivers et al., 2004). These response characteristics to same-sex sexual stimuli are important in examining various genders, including LGBT, and can provide valuable insights for discussions that go beyond sexual strategies theory.

Limitations and Directions for Future Research

While the findings of the current study are novel, there exist several limitations to be considered. As mentioned in the introduction, sexual arousal is a multifaceted concept that includes physical, subjective, emotional, and behavioral aspects (Bancroft et al., 2009). Among them, this study focused on the motivation to view sexual images in an experimental setting as indexed by the pay-per-view key-pressing responses. It is important to keep in mind that the pay-per-view responses are not the direct measures of actual sexual behaviors and physiological arousal. Sex differences in psychological reactions to sexual cues await further validation with physiological and subjective measurements. In addition, the visual stimuli we used were limited to images from Western models, while the participants in this study were Japanese. Some studies demonstrate that people are susceptible to recognition errors or biased emotional evaluation when target images are from an unfamiliar group rather than their own group (e.g., other-race-effect; Feng et al., 2012; Herrmann et al., 2007; Hugenberg et al., 2010). Although we confirmed in the preliminary experiment that Japanese viewers were able to evaluate sexual arousal consistently, it may be more appropriate to use sexually arousing images from the same cultural group. However, to the best of our knowledge, the image database including a Japanese erotic category is not publicly available yet. Our findings await validation from future studies by using images from the same and different groups. Lastly, we could not rule out the possibility that unidentified factors other than sexual arousal and the image categories of our image stimuli affected the viewing time in the pay-per-view task because of the lack of experimental control for the components constituting each image, such as the presence of faces, the number of persons, and so on. More detailed analysis is needed for a deeper understanding of what triggers the sex differences in the motivation to view sexual images.

Politics of children in same-sex marriages are like in heterosexual families; on the rare occasion a difference exists, people with same-sex female parents are more progressive, those with same-sex male parents are more conservative

Flores AR, Morrison M (2021) Potential differences between the political attitudes of people with same-sex parents and people with different-sex parents: An exploratory assessment of first-year college students. PLoS ONE 16(2): e0246929; Feb 25 2021. https://doi.org/10.1371/journal.pone.0246929

Rolf Degen disagrees: I would already question the unspoken premise of the above study, which is that parents imprint their political orientation on their children

Abstract: Children were often near the center of public debates about legal marriage recognition for same-sex couples. Obergefell v. Hodges (2015), the case that resulted in legal same-sex marriage recognition, stressed the importance of these children as one of many factors compelling the opinion. Estimates indicated same-sex couples were raising 200,000 children in the United States. Children raised by same-sex couples may be politically socialized in distinct ways compared to children of different-sex couples because lesbians, gay men, and bisexuals tend to hold distinct and progressive political viewpoints on a wide variety of issues. What are the political attitudes of people with same-sex parents? In this exploratory study, we analyze a large, representative survey of first-year college students across the United States; we find few differences between people with same-sex and different-sex parents, and some of those differences may be attributable to households and respondent characteristics. When on the rare occasion a difference exists, we find that people with same-sex female parents are more progressive, but people with same-sex male parents are more conservative. Gender differences also emerged, with some distinctive patterns between males with same-sex parents and females with same-sex parents.

Discussion

What are the political attitudes of people with SS parents, and do they differ from people with DS parents? Prior to matching, people with SS parents are more progressive, except for respondents with SS male parents, who are more conservative on gender equality in the workplace. Differences diminish after matching, suggesting background characteristics that distinguish people with SS parents from people with DS parents likely lead to those differences. We do not find that people with SS female or male parents are much different from people DS parents. Indeed, on some measures people with SS male parents are more conservative than similarly situated people with DS parents. This is contrary to what is expected, and it fails to support our hypothesis. Given the exploratory nature of our study, future work should see if our findings replicate in other samples.

There are potentially a few reasons why we do not find support for our expectations. First, there may be differences in the political attitudes of LGB persons who choose to become parents as compared to LGB people in general. For example, in the cumulative General Social Survey, LGB parents are more likely to be political independents than LGB people who are not parents (see S5 Appendix). Thus, LGB parents may not hold as distinctly progressive political attitudes as LGB people in general. This may be particularly important to explain the somewhat more conservative attitudes of people with SS male parents. Second, our sample is of entering college first-years, and this age cohort may be distinctively more progressive on politics [e.g., 52] such that the distinctiveness we would expect to find by having SS parents is muted by an overall more progressive sample. Third, the sample size of people with SS parents is small relative to people with DS parents. While there is a large sample in the HERI survey data, these null patterns may be due to a lack of analytical power. If this is the case, then pooling multiple years of the HERI data may reveal patterns that are significant and distinct.

Our findings further suggest that there are meaningful differences between SS female and SS male households. People with SS female parents have lower household incomes and are more racially and ethnically diverse than people with SS male parents. SS male couples face, on average, greater costs to become parents, and SS female couples are more likely to be raising biological children [2]. Thus, socialization may be different in SS female households and SS male households, and this may intersect with both race and class. This is further supported by the demographic differences we observed in the data, as people with SS female parents are more likely to self-identify as black and have lower household incomes. The overall effects of SS parentage are being primarily driven by both the type of SS couple and the gender of the respondent. Men with same-sex male parents are more conservative, but men with same-sex female parents are more progressive. As prior work indicates that there are differences in the political socialization of boys and girls [34], we find divergences between males and females with SS parents. That most of these differences are among males complements prior work that suggests boys have a more malleable orientation toward politics than girls [33]. Thus, both the gendered nature of politics and gendered differences in political socialization can explain the distinctive patterns we observe for men with SS parents.

There are limitations in our current exploration. The secondary analysis of survey data means that we lack the ability to control the questionnaire design. This means that we have only one indicator of SS parentage. Thus, we lack an opportunity to more fully understand the households and characteristics of the respondents. Our analysis would be more thorough if we had measures of length of time in a SS parent household, aspects of family formation (e.g., if children were biological from a previous heterosexual relationship, if children were born through surrogacy; or if children were adopted), and other aspects of family stability. Prior research suggests the family formation SS households are distinct from DS households [3], so these measures may identify distinct subgroups of individuals with SS parents where their political attitudes are distinct (e.g., people who have had a long tenure of having SS parents with no family disruptions versus people who only recently had SS parents). Future primary data collection efforts can move beyond the current study’s limitations by incorporating such measures to evaluate political attitudes with a fuller understanding of the family formation process. Even with its limitations, our study at least can incorporate some characteristics of parents, which enables us to make more direct comparisons with similarly situated people with DS parents. Large-N studies of political attitudes rarely incorporate such details [14], even though prior work suggests that such details are important to understanding identity and attitude formation [14,32].

Despite these limitations, we present novel data to explore the potential for the distinct political attitudes of people with SS parents. Parental socialization is occasionally a factor in the political orientations of people with SS parents, though in unanticipated ways.

An immigrant female chimpanzee copies an inefficient behaviour without clear function to mitigate risk of rejection in the new tribe

Zoo-housed female chimpanzee adopts local female-specific tradition upon immigrating into a new group. Zoë Goldsborough et al. Behaviour, Feb 25 2021. https://doi.org/10.1163/1568539X-bja10075

Abstract: Wild female chimpanzees typically migrate to a neighbouring community at the onset of sexual maturity, a process that can be dangerous and unpredictable. To mitigate the risk of rejection in the new community, immigrants may employ several behavioural strategies. During the integration of two chimpanzee females at Royal Burgers’ Zoo (Arnhem, The Netherlands) one of the immigrant females rapidly copied a local tradition — the crossed-arm walk — which has been present in the group for over 20 years. She copied the behaviour after meeting only one resident female, and showed the behaviour frequently throughout a 6-month observation period following the introduction. The other immigrant female never adopted the crossed-arm walk, highlighting the variation in behaviour by immigrants upon integration, as well as the potential associated consequences: in a separate observation period 2 years later, the female who copied the local tradition appeared more socially integrated than the other immigrant female.

Keywords: chimpanzees; social integration; social learning; behavioural copying; tradition

Check also Differences in nut-cracking efficiency between wild chimpanzee groups: Group belonging and conformity makes them to use inferior tools to be more prosocial

Costly culture: differences in nut-cracking efficiency between wild chimpanzee groups. Lydia V. Luncz et al. Animal Behaviour, Volume 137, March 2018, Pages 63-73. https://www.bipartisanalliance.com/2018/03/differences-in-nut-cracking-efficiency.html

4. Discussion

In this report, we describe how an immigrant female chimpanzee (Moni) copies an idiosyncratic group-specific behaviour soon after being introduced to a new group. Two days after first contact with a resident female (a crossed-arm walker), before meeting any other resident individuals, Moni engages in crossed-arm walking: an inefficient means of locomotion without clear function that is enacted by the majority of females in the new group. The immediacy of the acquisition of this behaviour by the immigrant, as well as the introduction context during which this behavioural copying occurred, both invite us to speculate that Moni may have enacted an integration strategy that facilitated social favourability (as suggested by Moni’s steep increase in social integration over time). Another immigrant female (Erika) who similarly encountered the crossed-arm walkers first and for similar durations during integration — yet never adopted the crossed-arm walk — did not exhibit marked improvements in social integration over time. These findings provide anecdotal evidence that behavioural copying might be an expression of social motivation which in conjunction may facilitate social acceptance in chimpanzees.

Anecdotal evidence should be treated with care (Sarringhaus et al., 2005; Sándor & Miklósi, 2020). Yet, it is noteworthy that the anecdote reported here does not stand on its own. There are at least two other reports showing that chimpanzees may copy behaviourally ineffective/functionless behaviour (Hobaiter & Byrne, 2010; van Leeuwen et al., 2014) and some indications that wild female chimpanzees may gradually (>1 year) adopt local conventions upon immigration (Luncz et al., 2012; Luncz & Boesch, 2014). Hence, it is conceivable that Moni strategically adopted the local convention. Moni’s behavioural copying upon immigration is further reminiscent of studies reporting conformity in migrating animals (Van de Waal et al., 2013; Luncz & Boesch, 2014; Aplin et al., 2015). Especially when individuals are uncertain of their predicament, for instance during migrations, the inclination to align oneself with the (new) majority can take precedence (van Bergen et al., 2004; Morgan et al., 2012; Smolla et al., 2016; Jones et al., 2018). It is noteworthy that chimpanzee introductions in captive settings are notoriously difficult, often resulting in protracted aggression and injuries (Brent et al., 1997). This may further incentivize immigrating individuals to gain social acceptance from the group. In this light, it is relevant to emphasize that Erika, the immigrant who did not copy the crossed-arm walk, was introduced to the new group together with her mother, Marlene. As such, Erika might have been less uncertain/insecure in her new environment compared to Moni, who was introduced alone and had been housed solitary for years prior to her arrival. By extending her behavioural repertoire with the local customary behaviour of crossed-arm walking, Moni might have alleviated her uncertainty by gaining social benefits as expressed by her expedited social integration. The possibility that Moni engaged in behavioural copying in order to increase social favourability is consistent with the fact that Moni selectively directed her grooming efforts towards the two most prolific crossed-arm walkers (Morami and Moniek). Interestingly, though, while crossed-arm walk is shown by the majority of the Burgers’ group, Moni first engaged in the behaviour after having met only one resident female. This suggests the workings of another yet related mechanism that could be sparked by uncertainty, namely copying the behaviour of the first individual one encounters (Galef & Whiskin, 2008; van Leeuwen et al., 2016).

Similarly, given that close affiliative relationships are thought to facilitate social learning (Bonnie & de Waal, 2006; Hobaiter et al., 2014; van Leeuwen et al., 2014; Lamon et al., 2017), it is also possible that Moni copied the crossed-arm walk from Morami given the nature of the social bonds between the females. According to the caretakers, Moni (but not Erika) and Morami responded very positively to one another when introduced, which is supported by the fact that they went from visual contact to sharing an enclosure within one day. However, as Moni engaged in the crossed-arm walk already two days after first meeting Morami, in our view, it is more plausible to infer that Moni proactively tried to establish connections by means of behavioural copying than the inverse alternative where Moni established close social bonds of which the behavioural copying was but an expression. This interpretation is corroborated by the observation that although Moni directed her grooming efforts selectively to Morami and Moniek, this directional social bonding behaviour was not selectively reciprocated. Interestingly, when an entire group of chimpanzees migrated to a resident group, the adoption of local behaviour by immigrant chimpanzees only occurred after affiliative social relationships had been formed (Watson et al., 2015). In conjunction, these findings suggest that chimpanzees may cope with immigration by converging toward locally adaptive information, but that the extent of experienced stress owing to uncertainty (higher when migrating alone — like Moni — than with familiar group members — like Erika and in the study by Watson and colleagues) moderates its immediacy.

To our knowledge, the crossed-arm walk is the first female-specific tradition in chimpanzees ever reported. While sex-specific preferences in play object choices have been found in juvenile chimpanzees (Kahlenberg & Wrangham, 2010), and sex differences in rates of social learning (Lonsdorf et al., 2004), there are no reports on sex-specific conventions in chimpanzees or primates in general. The crossed-arm walk tradition was presumably instigated by Morami, who was pregnant at the time. Given that the form of the crossed-arm walk (which closely resembles how a chimpanzee would carry an (deceased) infant), and the female-specific expression of the behaviour, it is tempting to speculate that maternal instincts could have played a role in the inception and spread of the behaviour. In this light, it is of interest to note that Erika is the only female in the group who has never had an infant.

The reported observations and inferences warrant differential scrutiny (Sándor & Miklósi, 2020). Moni’s adoption of the crossed-arm walk provides an objective account of chimpanzees’ capacity to copy behavioural sequences (Hobaiter & Byrne, 2010; van Leeuwen et al., 2014), yet proponents of the “zone of latent solutions” approach (Tennie et al., 2020) would challenge this notion by arguing that the crossed-arm walk was merely individually reinvented by Moni. In our view, however, the speed at which Moni adopted the crossed-arm walk, in conjunction with the idiosyncrasy of the crossed-arm walk posture/gait, defies — probabilistically — the reinvention hypothesis. The link between Moni’s crossed-arm walk adoption and her facilitated social integration compared to the immigrant who did not copy the crossed-arm walk (Erika) is impossible to prove based on the reported observations. There are myriad reasons why Moni might have become more socially integrated than Erika — for instance, a difference in personality, a difference in life histories (i.e., Moni was hand-raised while Erika was mother-reared), and the differences in introduction contexts. Events during the observation period could also have affected differences in integration, for instance, Moni experienced a stillbirth during Period 1 and received increased affiliation from certain group members afterwards (Goldsborough et al., 2020). Therefore, our anecdotal report could best be interpreted as (i) evidence that chimpanzees can (and are motivated to) alter their behaviour upon integration into a new group (likely owing to social influences), and (ii) a tentative pointer to the possibility that in non-human animals behavioural similarity may induce relative favourability, just like in humans (e.g., McPherson et al., 2001). Tracking behavioural responses of animals integrating into new groups may thus represent an interesting approach for examining animals’ phenotypic plasticity and exploring the evolutionary origins of behavioural copying and its ramifications for social acceptance.

I Want You to Want Me: A Qualitative Analysis of Heterosexual Men's Desire to Feel Desired in Intimate Relationships

I Want You to Want Me: A Qualitative Analysis of Heterosexual Men's Desire to Feel Desired in Intimate Relationships. Sarah Hunter Murray &Lori Brotto. Journal of Sex & Marital Therapy, Feb 24 2021. https://doi.org/10.1080/0092623X.2021.1888830

Abstract: Current sexual scripts for heterosexual relationships in the Western world stipulate that men should be the ones to initiate sexual activity, push to the next level of physical intimacy, and to desire women (and not be desirable themselves). However, there is building evidence that sexual scripts and gender roles are not only limited, they may be evolving and shifting over time. The purpose of the current study was to explore the degree to which feeling desired is considered important to heterosexual men in intimate relationships as well as how heterosexual men feel desired by their partners. Three hundred men between the ages of 18 and 65 were recruited from the online platform Reddit. Using Thematic Analysis, we determined that the vast majority of men in this study felt that feeling desired was very important to their sexual experiences. Men in this study listed several ways they felt desired, many that fell outside of traditional gender roles such as romantic, non-sexual touch and having women initiate sexual activity. The findings add to a growing body of literature which suggests traditional sexual scripts for heterosexual men may be limiting and not accurate for all men’s sexual experiences.

Daily stressors may serve as a proxy to engagement in social activities, where a lower level of engagement is related to better physical and emotional well-being but lower levels of cognitive functioning

Charles, S. T., Mogle, J., Chai, H. W., & Almeida, D. M. (2021). The mixed benefits of a stressor-free life. Emotion., Feb 2021. https://doi.org/10.1037/emo0000958

Abstract: Research documents the pernicious effects of daily stressors on well-being, but often ignored in these studies are people reporting no stressors. The current study compared adults who reported no daily stressors with adults who reported at least one stressor across 8 consecutive days on measures of well-being. Of the 2,804 respondents (age range = 25–75 years, M = 53.46) from the Midlife in the United State Survey daily diary study, 10% reported experiencing no stressors across 8 days. Those reporting no stressors were generally older, male, unmarried, and were less likely to work, provide or receive emotional support, or experience positive daily events. They reported greater daily affective well-being and fewer chronic health conditions but had lower levels of cognitive functioning. Findings suggest that daily stressors may serve as a proxy to engagement in social activities, where a lower level of engagement is related to better physical and emotional well-being but lower levels of cognitive functioning.