Chest beats as an honest signal of body size in male mountain gorillas: Positive correlations among male body size, dominance rank and reproductive success

Chest beats as an honest signal of body size in male mountain gorillas (Gorilla beringei beringei). Edward Wright, Sven Grawunder, Eric Ndayishimiye, Jordi Galbany, Shannon C. McFarlin, Tara S. Stoinski & Martha M. Robbins. Scientific Reports volume 11, Article number: 6879. Apr 8 2021. https://www.nature.com/articles/s41598-021-86261-8

Abstract: Acoustic signals that reliably indicate body size, which usually determines competitive ability, are of particular interest for understanding how animals assess rivals and choose mates. Whereas body size tends to be negatively associated with formant dispersion in animal vocalizations, non-vocal signals have received little attention. Among the most emblematic sounds in the animal kingdom is the chest beat of gorillas, a non-vocal signal that is thought to be important in intra and inter-sexual competition, yet it is unclear whether it reliably indicates body size. We examined the relationship among body size (back breadth), peak frequency, and three temporal characteristics of the chest beat: duration, number of beats and beat rate from sound recordings of wild adult male mountain gorillas. Using linear mixed models, we found that larger males had significantly lower peak frequencies than smaller ones, but we found no consistent relationship between body size and the temporal characteristics measured. Taken together with earlier findings of positive correlations among male body size, dominance rank and reproductive success, we conclude that the gorilla chest beat is an honest signal of competitive ability. These results emphasize the potential of non-vocal signals to convey important information in mammal communication.

Discussion

Our results indicate that mountain gorilla chest beats reliably convey information about the body size of the sender. Larger males consistently emitted chest beats with lower median peak frequencies than smaller males. This finding is an important contribution to the growing literature on honest signaling of body size in acoustic communication, which has predominantly focused on vocalizations5,10,11,12,13,14,15,16,17,18. This is one of a few studies in mammals demonstrating that body size is reliably encoded in a non-vocal acoustic signal. In eland bulls, body size (skeletal measures and muscle mass) was shown to be negatively correlated with the peak frequency of knee clicks21. In adult male gorillas, body size (a composite measure combining crest height and back breadth) is thought to reflect competitive ability because it correlates with dominance rank in multi-male groups and reproductive success31. Additionally, silverbacks chest beat more frequently on days when females are in estrous, presumably as a courtship display28. Taken together, this strongly suggests that the chest beat is an extremely important signal in intrasexual competition and intersexual mate choice in gorillas. Moreover, given that different forms of drumming behaviour, incorporating substrates other than the chest or body, are surprisingly common in a wide range of animals19,20, it is likely that this understudied non-vocal acoustic mode of communication functions to reliably indicate competitive ability in many other species as well.

Our measure of body size, back breadth, likely correlates with a range of morphological traits, including chest volume, pulmonary capacity and hand size. Therefore it is unclear which specific trait or traits are responsible for driving the inverse relationship between back breadth and peak frequency. Moreover, gorillas like other non-human primates possess laryngeal air sacs which are thought to act as resonators, enhancing acoustic signals4,11,24. Indeed, gorillas appear to use laryngeal air sacs during growling vocalizations which often accompany chest beating24. The volume of laryngeal air sacs is likely to be directly correlated with body size, at least within-species (which in orangutans (Pongo) can reach a massive 6 L38). Thus larger males are expected to have larger laryngeal air sacs than smaller males, further lowering the resonating non-vocal frequencies produced whilst chest beating. However, our knowledge of the size and function of laryngeal air sacs in primates and other taxa remains poor39.

Both dominant and subordinate male gorillas emitted chest beats. In general, gorilla males likely chest beat to attract estrous females and intimidate rivals22,28,31. However, younger subordinate males may also chest beat as a means to fine tune this signal and acquire social feedback from conspecifics. The importance of practice is evident as infants as young as one year of age commonly start emitting chest beats during social play22,40. Interestingly, the chest beat rate (number of chest beats per unit time) in the current study (2014–2016) was over three times higher than what was previously reported (1968–1969)23. We are unsure why this is the case, but it could be due to a number of different factors, including a higher number of estrous females per group, younger males, or more intergroup encounters over time41.

Even though we have demonstrated that chest beats reliably convey the body size of the emitter, future studies need to show that receivers actually attend to this information. Gorilla chest beats are thought to play a key role in male–male competition allowing individuals to assess the fighting ability of competitors and thus influence whether they should initiate, escalate or retreat in intra- and intergroup contests22,31,42. Similarly, male gelada baboons (Theropithecus gelada) assess the competitive ability of rivals through vocalizations and compare it to their own, governing how they respond in contests43. Intense contact aggression between males is infrequent in gorillas, which is presumed to reflect the high costs of aggression and their ability to resolve conflicts without resorting to this high risk behaviour (within-group31,42; between-group44). We expect that chest beats to also play a critical role in mate choice22,28,45, providing females with information about the size of the males in their own group and in neighbouring groups, which may influence their decision to transfer to another group. Larger alpha males lead groups with more adult females than smaller males, strongly suggesting that females actively chose to transfer into groups with large alpha males29,30,31. Gorillas may be similar to red deer hinds in their ability to discriminate between the acoustic signals of their current harem-holder stag and those of neighbouring stags46. Lastly, because chest beats can be heard over long-distances, we predict that both male size and the number of different males emitting chest beats are two important factors influencing group movement. Recent work in Bwindi mountain gorillas speculated that one of the functions of chest beats is to mediate how groups use space, with smaller groups with fewer adult males likely avoiding larger ones with more males, which would help to explain their findings that larger groups having more exclusive home ranges and core areas than smaller groups47.

We found no support for body size to influence the duration of chest beats, the number of beats, or the beat rate. Acoustic signals are thought to be energetically expensive to produce34,35,36,37 and we expected chest beats to be as well, with anecdotal accounts of gorillas that emit a high frequency of chest beats showing signs of exhaustion (personal observation). This is in contrast to studies of savannah baboons (Papio ursinus), showing that males with higher competitive ability produce longer vocalizations than weaker ones48,49. It is possible that the duration of chest beats (and the beat rate) decreases over time during periods of high chest beating frequency, and this decrease may be stronger in smaller males. In general the relationship between body size and the duration of vocalizations and other acoustic sounds has been understudied in mammals4,50.

In addition to conveying information on body size (and other phenotypic traits), we would expect it to be important for chest beats to be individual-specific, thereby allowing receivers to discriminate the identity of the emitter. Further study is needed to determine if there are individual signatures to the chest beats. Interestingly, we found smaller within-individual than between-individual coefficients of variation, particularly for chest beat duration and number of beats (39.0 vs. 85% and 31.6 vs. 67.9%, respectively). Notably, several temporal aspects of non-vocal drumming displays by chimpanzees (Pan troglodytes), ruffed grouse (Bonasa umbellus) and great spotted woodpeckers (Dendrocopos major) show significant individual variation, similar to many vocalizations in a wide range of species19,51,52. For example, the buttress drumming of individual chimpanzees significantly differ in the mean duration and the mean number of beats52,53.

The gorilla chest beat has both an acoustic and visual component, making it a multimodal signal. Individuals in visual proximity can benefit from seeing and hearing the gorilla emitting the chest beat, whereas individuals further away rely on the acoustic component. Researchers have been interested in determining whether the different components of multimodal signals convey the same (redundant signal or backup hypothesis) or different information (multiple messages hypotheses)54. Gorillas live in tropical forests with dense vegetation, meaning that it is often difficult to see conspecifics even if they are close by. Therefore, we argue that the evolution of the chest beat as a multimodal signal is at least in part to enhance signal transmission in an environment with limited visibility. We would expect the same messages to be transmitted in both visual and acoustic modalities, which would provide support for the redundant signal hypothesis. However, these two hypotheses are not mutually exclusive, as the chest beat signal may transmit additional information, other than body size, which is then repeated in the visual and acoustic modalities, providing support for both hypotheses.

Women endorsed self-estimates of storge (friendship and intimacy), pragma (practical ventures) and agape (altruistic love) more than men did; males assessed their female partners higher in mania (obsession and possessiveness)

Gender Differences in Estimates of Love Styles for Self and Others. Félix Neto. Sexuality & Culture, Apr 6 2021. https://link.springer.com/article/10.1007/s12119-021-09855-4

Abstract: This study investigated gender differences in how people estimate the intensity and style of love in themselves and in others. The six orientations toward love analyzed were: Eros (sex and passion), Ludus (game-playing), Storge (friendship and intimacy), Pragma (practical ventures), Mania (obsession and possessiveness), and Agape (altruistic love). The sample included 265 students (170 females and 95 males). Respondents evaluated their parents’, romantic partners’, and own overall love and the six love styles. Women endorsed self-estimates of storge, pragma and agape more than men did. Males assessed their female partners higher in mania. Gender differences in estimates of parental love styles were not found. Concerning self-partner differences, participants estimated their partners as being higher in ludic and manic love. Regarding generational differences, children well-tended to assess themselves higher in love than their fathers and mothers. Multiple regressions indicated that erotic, storgic and agapic love styles were significant predictors of overall love for self, romantic partners, and parents. Results are discussed with reference to previous research and some suggestions for further research are also noted.

How Social Relationships Shape Moral Judgment

Earp, Brian D., Killian L. McLoughlin, Joshua Monrad, Margaret S. Clark, and Molly Crockett. 2020. “How Social Relationships Shape Moral Judgment.” PsyArXiv. September 18. osf.io/e7cgq

Abstract: Our judgments of whether an action is morally wrong depend on who is involved and their relationship to one another. But how, when, and why do social relationships shape such judgments? Here we provide new theory and evidence to address this question. In a pre- registered study of U.S. participants (n = 423, nationally representative for age, race and gender), we show that particular social relationships (like those between romantic partners, housemates, or siblings) are normatively expected to serve distinct cooperative functions – including care, reciprocity, hierarchy, and mating – to different degrees. In a second pre- registered study (n = 1,320) we show that these relationship-specific norms, in turn, influence the severity of moral judgments concerning the wrongness of actions that violate cooperative expectations. These data provide evidence for a unifying theory of relational morality that makes highly precise out-of-sample predictions about specific patterns of moral judgments across relationships. Our findings show how the perceived morality of actions depends not only on the actions themselves, but also on the relational context in which those actions occur.

These results support claims that dogs display jealous behavior, and they provide the first evidence that dogs can mentally represent jealousy-inducing social interactions

Dogs Mentally Represent Jealousy-Inducing Social Interactions. Amalia P. M. Bastos et al. Psychological Science, April 7, 2021. https://doi.org/10.1177/0956797620979149

Abstract: Jealousy may have evolved to protect valuable social bonds from interlopers, but some researchers have suggested that it is linked to self-awareness and theory of mind, leading to claims that it is unique to humans. We presented dogs (N = 18; 11 females; age: M = 4.6 years, SD = 1.9) with situations in which they could observe an out-of-sight social interaction between their owner and a fake dog or between their owner and a fleece cylinder. We found evidence for three signatures of jealous behavior in dogs: (a) Jealousy emerged only when the dog’s owner interacted with a perceived social rival, (b) it occurred as a consequence of that interaction and not because of the mere presence of a conspecific, and (c) it emerged even for an out-of-sight interaction between the dog’s owner and a social rival. These results support claims that dogs display jealous behavior, and they provide the first evidence that dogs can mentally represent jealousy-inducing social interactions.

Keywords: dogs, secondary emotion, jealous behavior, jealousy, mental representation, open data

Overall, martial arts & combat sports have no relationship with more or less anger or aggression levels

Effects of martial arts and combat sports training on anger and aggression: A systematic review. Jorge Lafuente, Marta Zubiaur, Carlos Gutiérrez-García. Aggression and Violent Behavior, April 9 2021, 101611. https://doi.org/10.1016/j.avb.2021.101611

Highlights

• The available evidence shows unclear relationship between MA&CS practice and anger and aggression levels.

• However, training in traditional martial arts, which affects meditation, philosophy or kata, seems to be an effective means to lower levels of anger and aggression.

• Regarding the age of subjects, there is a predisposition to reduce anger in the adult population.

• In addition, young subjects with violent or behavioral problems show a positive response to working with martial arts

Abstract: Martial Arts and combat sports (MA&CS) are the subject of a dispute. On the one hand, they have been considered an ideal means to acquire emotional self-control. On the other hand, they have been considered aggressive practices which may promote violent behaviors. The current systematic review aims to analyze the evidence of the effects of MA&CS participation in anger and aggression, and the quality of this evidence. The review was conducted according to the PRISMA-P protocol. The studied variables were study type and aims, sample, interventions and procedures, measurements and outcomes. Nine studies (three cohort studies and six randomized controlled trials) were selected for inclusion. The following results should be viewed with much caution, as the volume of studies and the methodological quality of most of them is not optimal. Training in traditional martial arts seems to be an effective means to lower levels of anger and aggression. Regarding the age of subjects, there is a predisposition to reduce anger in the adult population. In addition, young subjects with violent or behavioral problems show a positive response to working with martial arts. However, the available evidence, overall, shows no relationship between MA&CS practice and anger and aggression levels.

Keywords: Martial artsCombat sportsAngerAggressionReview

Bodies were perceived as more threatening as they had added musculature & portliness, & less threatening with more emaciation, but threatening faces exerted the most influence when paired with non-threatening bodies

McElvaney TJ, Osman M, Mareschal I (2021) Perceiving threat in others: The role of body morphology. PLoS ONE 16(4): e0249782, Apr 8 2021. https://doi.org/10.1371/journal.pone.0249782

Abstract: People make judgments of others based on appearance, and these inferences can affect social interactions. Although the importance of facial appearance in these judgments is well established, the impact of the body morphology remains unclear. Specifically, it is unknown whether experimentally varied body morphology has an impact on perception of threat in others. In two preregistered experiments (N = 250), participants made judgments of perceived threat of body stimuli of varying morphology, both in the absence (Experiment 1) and presence (Experiment 2) of facial information. Bodies were perceived as more threatening as they increased in mass with added musculature and portliness, and less threatening as they increased in emaciation. The impact of musculature endured even in the presence of faces, although faces contributed more to the overall threat judgment. The relative contributions of the faces and bodies seemed to be driven by discordance, such that threatening faces exerted the most influence when paired with non-threatening bodies, and vice versa. This suggests that the faces and bodies were not perceived as entirely independent and separate components. Overall, these findings suggest that body morphology plays an important role in perceived threat and may bias real-world judgments.

4. Discussion

In two preregistered studies, we found evidence supporting the hypothesis that systematic changes in body morphology can significantly influence how threatening a person appears. Judgment of threat was primarily driven by facial information, with the odds of perceiving a person as more threatening increasing nearly threefold with each unit increase in perceived facial threat. However, larger bodies also tended to be seen as more threatening than smaller bodies, both in the absence and presence of facial information. Indeed, the odds of perceiving a person as more threatening increased more than one and a half-fold with each unit increase in perceived body threat. While the association between body size and perceived negative traits is not novel, this represents the first study, to our knowledge, to demonstrate that perceived threat can shift significantly with systematic changes in body morphology. Using this methodology, we were able to directly measure the effects of body morphology on perceived threat. In Experiment 1, bodies were perceived as more threatening the larger they became, most notably with increased musculature. This finding was replicated in Experiment 2.

Our findings are consistent with Palmer-Hague, Twele & Fuller [30], who found that perceived threat in facial stimuli was significantly predicted by BMI. They are also somewhat in line with Hu et al. [25], who found that more muscular builds tend to be seen as more dominant. More generally, these results dovetail with the growing literature on the capacity of appearance to significantly affect character trait inferences, while also adding to the sizeable obesity stigma literature. It appears that larger people may be perceived as more threatening. This would make sense from an ecological theory perspective, with size potentially serving as an inferred cue of strength. This increased perceived threat may contribute to biases against larger people [28, 29]. For example, in the realm of courtroom decision-making, it has been shown that defendants who appear untrustworthy are more likely to fall victim to harsher sentencing [6]. It is conceivable that people who appear threatening may also be more severely judged.

The study also contributes to the literature on the joint processing of bodies and faces. In line with the emotion recognition literature, we found that two stimuli sharing the same facial information can be perceived as significantly different depending on body information. This common interaction of face and body information in both this study and previous work on emotion recognition is perhaps unsurprising given the link between emotions and trait perception. The perception of emotional expressions has been shown to fuel, and can directly contribute to, overgeneralisations about other people’s trait characteristics [45–47]. Indeed, work by Montepare & Dobish [48] showed that actors posed with angry emotional expressions were perceived to be high in trait dominance and low in trait affiliation, while actors posing with surprise and happiness were seen as high in both trait dominance and affiliation.

However, the current study diverges from findings in emotion perception in the nature of the observed interaction of the face and body information. In contrast with work on combined emotional faces and bodies stimuli [15, 43], the contribution of the body here was maximised when paired with faces of low threat signal, rather than ambiguous threat signal. This could be attributable to the more transient nature of emotions in comparison to more stable character traits. Emotions are short and distinct feelings, which tend to have a specific cause [17], while character traits tend to be consistent over many years [18]. Similarly, the perceived emotion of a face can be rather malleable, and highly dependent on contextual and body cues [13]. Hence, contextual cues may be of particular importance when the facial cue is ambiguous. However, a face that signals a “neutral” level of a character trait such as threat may not be ambiguous or uninterpretable. Rather, it may be signalling a “medium” level of threat, an amount that can be processed and interpreted.

These results suggest that, rather than simply summing the independent threat level of the face and body, the two are integrated into a single judgment, that tends to be more heavily driven by the face. In this way, the perception of the compounds diverged from the mere sum of their separately perceived properties. The relative contributions of face and body seem to be driven by discordance, with faces exercising their greatest influence when paired with discordant bodies, and vice versa. This may be attributable to a pop-out effect, in that faces that may not appear to “match” the accompanying body (and vice versa) may be more likely to capture attention, and thus more strongly drive the judgment of the overall compound [49]. Although not providing direct evidence for holistic processing per se, this significant interaction lends some support to the hypothesis forwarded by Aviezer, Trope & Todorov [10]; that people do not perceive others as separate body and face components. Rather, it seems likely they are perceived as elements of a greater, whole-person unit. In this case, the signals of threat from face and body are integrated such that their respective strengths are dependent on the nature of their paired signal. The holistic person-perception hypothesis has found rather consistent support, from the emotion/identity identification literature [11] to findings on gaze detection [12]. However, this study represents the first evidence for such complimentary face and body processing in the area of trait/character inference.

While we found strong evidence for our primary hypotheses, we found no effect of participant height or BMI on perceived threat. This could be attributed to the manner in which the stimuli were presented. Participants were presented with an image on screen, as opposed to judging a real-sized potential threat. In a more realistic environment, it may be that people judge potential threats in terms of the personal threat posed. In this sense, a large person may feel less threatened by a person of average build than would a small person. Here, the potential effect of relative size may have been nullified. In addition, we found that the relation between perceived attractiveness and perceived threat was somewhat inconsistent. Although more attractive faces were perceived as less threatening, males found more attractive muscular bodies to be more threatening in Experiment 1. This may be due to the male participants not finding the bodies attractive in a romantic sense, but rather in recognition of a typically attractive male form [50]. In this case, the more muscular bodies were perceived as more attractive, but did not detract from the signalled threat. However, as the current study did not record the sexual orientation of the participants, this interpretation is somewhat speculative. Future studies investigating perceived attractiveness and threat should record the sexual orientation of participants to elucidate more clearly the nature of this interaction.

In addition to our primary hypotheses, we also observed significant effects of age and education in our first experiment. Older participants tended to perceive less threat in the stimuli, which is in line with previous work [39]. Contrary to expectations, it was also noted that participants with third-level degrees tended to perceive more threat than those without a degree, which is contrary to previous indications that participants of lower educational status show more hostile reactivity to ambiguous social scenarios [40]. However, it has also been shown that those of lower social rank and education may be more adept at tracking hostility [40]. As our stimuli did not overtly indicate hostility, these participants may have thus ascribed lower threat ratings.

A number of limitations of the current study should be mentioned. First, our study was limited to body stimuli which consisted entirely of images of white males. In order to generalise these findings, it would be useful to replicate the study using both female and male stimuli. It would be particularly relevant to repeat this with stimuli of varying races given the documented bias of young black men being perceived as bigger and more physically threatening than white men [51, 52]. Furthermore, our stimuli were entirely CG. While this lent us a level of control over body morphology that would have been impossible with images of real people, it limits the ecological validity of our findings. Future studies could attempt to use photo-editing software to systematically vary the body morphology of images of real people. Finally, the stimuli presented in this study were relatively small, displayed on a computer screen. A study utilising virtual reality (VR) apparatus [53] to display life-sized human stimuli to participants, while manipulating facial information and body morphology, may tap into a more ecological measurement of perceived threat. Furthermore, a VR study could also manipulate the participants’ own virtual height, thus exploring the impact of discrepant size on perceptions of threat.

This study reinforces the notion that morningness and eveningness as explicit identities are associated with political ideology: Author found a relationship between morning orientation and conservatism

Political ideology and diurnal associations: A dual-process motivated social cognition account. Aleksander Ksiazkiewicz. Politics and the Life Sciences , First View , pp. 1 - 16, Apr 8 2021. https://doi.org/10.1017/pls.2021.4

Abstract: Social scientists have begun to uncover links between sleep and political attitudes and behaviors. This registered report considers how diurnal morning-night associations relate to political ideology using data from the Attitudes, Identities, and Individual Differences Study, a large-scale online data collection effort. Measures encompass perceived cultural attitudes and social pressures regarding diurnal preferences and explicit and implicit measures of both morning-night attitudes and morning-night self-concepts. Together, the analyses demonstrate a relationship between morning orientation and conservatism for explicit morning-night self-concepts and, to a lesser extent, explicit morning-night attitudes. This relationship is not present for implicit associations, and associations with perceived cultural attitudes and social pressure are also largely absent. This study reinforces the notion that morningness and eveningness as explicit identities are associated with political ideology.

Attending to Social Information: What Makes Men Less Desirable

Attending to Social Information: What Makes Men Less Desirable. Ryan C. Anderson. Sexuality & Culture, Apr 8 2021. https://rd.springer.com/article/10.1007/s12119-021-09858-1

Abstract: Mate copying is a type of social influence whereby the desirability of a potential mate is modified as a result of being romantically chosen by an opposite-sex other. While research into mate copying typically focuses on how an individual’s desirability can be raised by having a previous partner, it can also be lowered. Here we present two studies that look at how a previous partner can influence how one is romantically perceived. Study 1 presented women (N = 103) with profiles of men alongside mate-relevant information offered by the former partners of the men, and had them rate the long-term desirability of the featured men. Using a similar methodology, Study 2 (N = 284) varied who was providing the information. Study 1 found that a man’s perceived desirability is lowered when a previous partner offers negative information about the relationship. Study 2 found that a man’s perceived romantic desirability can be lowered depending on who his previous partner was and how long they were romantically associated for. It was concluded that relationship decisions about a prospective romantic partner are influenced by both implicit and explicit information provided by their former partners.

Rolf Degen summarizing... People tend to belittle the extent of their meat consumption to mitigate the cognitive dissonance triggered by the meat paradox

Meat‐related cognitive dissonance: The social psychology of eating animals. Hank Rothgerber  Daniel L. Rosenfeld. Social and Personality Psychology Compass, April 7 2021. https://doi.org/10.1111/spc3.12592

Rolf Degen's take: https://twitter.com/DegenRolf/status/1380174005051740172

Abstract: As the practice of eating animals as meat faces increased scrutiny for its ethical, health, and environmental implications, a subfield devoted to its psychology has begun to flourish. Researchers have been especially interested in understanding how individuals morally care for animals and wish them no harm yet simultaneously eat them as food. Merging theories of cognitive dissonance, moral disengagement, and neutralization, the current review aims to provide a framework of meat‐related cognitive dissonance (MRCD) that explains this belief–behavior inconsistency. First, we evaluate the existing research on mechanisms that (a) prevent MRCD from occurring and (b) reduce MRCD once it has occurred. Second, we highlight promising avenues for further research on MRCD. The purpose of this review, ultimately, is to synthesize findings from this emerging area of research and to highlight its exciting future directions for the field of social psychology.

People tend to assign higher attractiveness to an individual viewed from the back than head on; this tendency is pronounced when males rate the attractiveness of women

Romantic Bias in Judging the Attractiveness of Faces from the Back. Fuka Ichimura, Miho Moriwaki & Atsunori Ariga. Journal of Nonverbal Behavior, Apr 8 2021. https://rd.springer.com/article/10.1007/s10919-021-00361-7

Abstract: People tend to assign higher attractiveness to an individual viewed from the back than head on. This tendency is pronounced when males rate the attractiveness of women. This study investigated reasons for the previously observed gender difference in this bias, focusing on the social relationship between raters (participants) and rated models (stimuli). To manipulate the assumed social relationship, we explicitly instructed participants in advance to rate the front/back view of an opposite-gender individual as a romantic partner (romance-based condition) or as a friend (friend-based condition). The back-view bias was robustly observed in both male and female raters under every condition. More importantly, male raters showed an enhanced back-view bias under the romance-based condition compared to the friend-based condition, whereas female raters showed less bias, irrespective of the assumed social relationship. We discuss these results in terms of gender differences in criteria used to form judgments of attractiveness.

Attractive people are not only seen more favorably, but also more accurately, maybe due to their acceptance being relatively decoupled from their behaviors, which lowers inhibitions and allow for better "study" of their personalities

The Good Target of Personality Judgments. Marie-Catherine Mignault and Lauren J. Human. In The Oxford Handbook of Accurate Personality Judgment, edited by Tera D. Letzring and Jana S. Spain. Mar 2021, DOI 10.1093/oxfordhb/9780190912529.013.7

Abstract: Being a good target, judgeable, or high in expressive accuracy plays a fundamental role in the accuracy of personality judgments. In line with Funder’s realistic accuracy model (RAM), targets are responsible for the quality and quantity of information—or cues—they provide to judges, and have the potential to influence how much attention and cognitive resources judges dedicate to those cues. In this chapter, target characteristics are discussed, such as psychological adjustment and social skills, which influence each stage of the RAM, thereby distinguishing good targets from targets that are more elusive or difficult to read. To conclude, possible intra- and inter-personal benefits of expressive accuracy and potential ways to enhance expressive accuracy are considered.

Keywords: good target, judgeability, expressive accuracy, personality judgment, psychological adjustment, social skill, realistic accuracy model

Estimating the Effect Size of Moral Contagion in Online Networks: Each message is 12% more likely to be shared for each additional moral-emotional word

Brady, William J., and Jay J. Van Bavel. 2021. “Estimating the Effect Size of Moral Contagion in Online Networks: A Pre-registered Replication and Meta-analysis.” OSF Preprints. April 7. doi:10.31219/osf.io/s4w2x

Abstract: Over 4 billion people now use social media platforms. As our social lives become more entangled than ever before with online social networks, it is important to understand the dynamics of online information diffusion. This is particularly true for the political domain, as political elites, disinformation profiteers and social activists all utilize social media to gain influence by spreading information. Recent work found that emotional expressions related to the domain of morality (moral emotion expression) are associated with increased diffusion of political messages--a phenomenon we called ‘moral contagion’. Here, we perform a large, pre-registered direct replication (N = 849,266) of Brady et al. (2017), as well as a meta-analysis of all available data testing moral contagion (5 independent labs, 27 studies, N = 4,821,006). The estimate of moral contagion in the available population of studies is positive and significant (IRR = 1.12, 95% CI = [1.06, 1.19]), such that each message is 12% more likely to be shared for each additional moral-emotional word. The mean effect size of the large, pre-registered replication (IRR = 1.15) better estimated the effect size of the available population of studies than the original study (IRR = 1.20). These findings reinforce the importance of replication and producing a pre-registered analysis to generate accurate estimates of effect size for future studies.

Rolf Degen summarizing... People are surprisingly reluctant to pressure others to behave prosocially, even if they themselves would act prosocially

Do People Intervene to Make Others Behave Prosocially? Viola Ackfeld, Axel Ockenfels. Games and Economic Behavior, April 6 2021. https://doi.org/10.1016/j.geb.2021.03.005

Rolf Degen's take: https://twitter.com/DegenRolf/status/1379814104395882496

Abstract: We experimentally investigate people's willingness to intervene in others' decision-making in order to promote a charitable donation. We find that only a minority of those subjects who would donate themselves enforce the donation by banning the selfish choice from the decision-maker's choice menu. Bans are more acceptable if they are implemented only after the decision-makers could choose between the selfish and the prosocial option themselves. Also, many subjects decide against offering decision-makers a monetary incentive to switch from the selfish to the prosocial choice. We discuss potential hypotheses about underlying motivations for the (non-) usage of interventions, with a special focus on the hypothesis that interventions to promote prosocial choice are more acceptable the more they respect the autonomy of others.

Keywords: Charity experimentProsocial behaviorAutonomyBansIncentives

Pursued & implemented past civic activism in the offline sphere can mobilize further durable online political participation; the path from online to offline form of political behavior was found to be non-significant

A longitudinal study of the bidirectional causal relationships between online political participation and offline collective action. Maria Chayinska, Daniel Miranda, Roberto González. Computers in Human Behavior, April 7 2021, 106810. https://doi.org/10.1016/j.chb.2021.106810

Highlights

•Using an exploratory approach, the present study provides a rigorous analysis of the bidirectional causal relationships between online political participation and offline collective action by assessing the strength, the direction, the dynamics, and the persistence of their effects in the real-life study context.

•Two longitudinal panel studies were conducted among university students (Study 1) and nationally representative sample of adults (Study 2) in the socio-political context of Chile.

•Using longitudinal cross-lagged modelling, the study provides compelling longitudinal evidence to the assumption that pursued and implemented past civic activism in the offline sphere can mobilize further durable online political participation, whereas the reverse path from online to offline form of political behavior was found to be consistently non-significant.

Abstract: The longitudinal causal relationships between individuals’ online and offline forms of civic participation requires further understanding. We provide a robust test of four competing theoretical perspectives to establish the direction of causality between online political participation and offline collective action as well as the persistence of their longitudinal effects. Two longitudinal panel studies were conducted in the socio-political context of Chile. Study 1 involved university students (a 2-year, 5-wave longitudinal study, N wave 1 = 1221, N wave 2 = 954, N wave 3 = 943, N wave 4 = 905, and N wave 5 = 786) and Study 2 used a nationally representative sample of adults (a 3-year, 3-wave longitudinal study, N wave 1 = 2927, N wave 2 = 2473 and N wave 3 = 2229). Results from both studies supported the spillover perspective compellingly showing that offline participation fostered subsequent online collective action over time, whereas the reverse causal path from online political participation and offline collective action was consistently non-significant. In Study 2, previous offline collective action predicted increased online participation after controlling for the effects of age, gender, and educational level. The need for further fine-grained longitudinal research on the causal relations between offline and online collective action is discussed.

Keywords: collective actioncivic activismlongitudinal studyprotestChile

Exploring the relationship between sex and gender, country income level, and COVID-19

Recorded but not revealed: exploring the relationship between sex and gender, country income level, and COVID-19. Sarah Hawkes et al. The Lancet, April 06, 2021. https://doi.org/10.1016/S2214-109X(21)00170-4

In 2020 we witnessed a seeming exponential spread of information about COVID-19. From understanding the pathogen to understanding its effect on populations, we have a wealth of evidence for decision making in pandemic control. Nonetheless, there remain some fundamental areas of investigation and response for which evidence remains oddly and inconsistently absent. The role of sex and gender in understanding the testing-to-outcome pathway of the pandemic is one such area.

Identifying the contribution of sex and gender to SARS-CoV-2 infection yields important evidence on both biological mechanisms that underlie differences in illness outcomes,1 and social and structural dynamics that influence individuals' risk and vulnerability depending on their position in the gender hierarchy in any country or community.2 Such information can help identify sites for tailored individual-level and population-level health interventions that are more responsive to sex and gender and potentially more effective. The minimum starting point for analysing the contribution of sex and gender to the COVID-19 pandemic, and identifying opportunities for reducing health inequities, requires data that is sex-disaggregated, which can be analysed to understand and explain gendered inequalities.3

---

As we move towards the global distribution of COVID-19 vaccines, we believe that this moment must serve as a wake-up call for the importance of recording sex-disaggregated data accompanied by gender analysis. Monitoring the coverage of the vaccine by sex will be a vital component of ensuring equity and promoting equality. It could lead to more effective vaccine programmes. For example, a population-based survey in the USA found higher rates of COVID-19 vaccine scepticism in females compared with males.

10

 Will vaccine scepticism lead to lower uptake rates in women? We will not know unless we acknowledge that the purpose of sex-disaggregated data is not only to record it, but also to reveal it publicly, analyse it (including from a gender perspective) and, crucially, act on it.

Infidelity in Relation to Sex and Gender: The Perspective of Sociobiology Versus the Perspective of Sociology of Emotions

Infidelity in Relation to Sex and Gender: The Perspective of Sociobiology Versus the Perspective of Sociology of Emotions. Joanna Wróblewska-Skrzek. Sexuality & Culture, Apr 7 2021. https://rd.springer.com/article/10.1007/s12119-021-09845-6

Abstract: It is not the main intention of this paper to prove that people are unfaithful, neither does it present the scale of the phenomenon, as it is hard, for objective reasons, to obtain reliable data on the subject. The text analyses the motives for, and consequences of infidelity from two different perspectives: sociobiology and the sociology of emotions, while gender constitutes the axis of analysis. Regardless of whether we will explain infidelity as motivated by human nature, drives, desires and genes, or treat it as a social construct, the argumentation for infidelity remains different for men and for women. What is more, both subdisciplines bring into light different consequences of infidelity for representatives of either sex.

Cultural Correlates of Infidelity

Ulrick Beck and Elisabeth Beck-Gernsheim, having analyzed different types of sexual behaviors among men and women, propose a solution which centers around the cultural differences regarding sexuality and love. In their opinion, the development of a relationship between two sexes, starting with the first meeting and finishing with the sexual intercourse, proceeds according to an invisible protocol, socially pre-defined, of which the individual is usually completely unaware (Beck & Beck-Gernsheim, 2013, p. 87). Not biology, but culture and the process of socialization, especially socialization towards gender roles, plays a decisive role in this process.

Biological explanations of human sexual drives are discarded with the concept of social scripting developed by Edwarda Otto Laumanna and Johna Henry Gagnona. The idea is based on the assumptions that: (1) patterns of sexual behaviors are shaped culturally and locally, which means that the designates of the word “sex” [i.e. sexual intercourse] can vary extremely across cultures; (2) throughout their lives individuals accumulate social scripts of sexual behavior, including those considered deviant in their culture, by means of primary and secondary socialization, e.g. through media; (3) individuals are only “mirrors reflecting social patterns of sexual behaviors, although they can modify them, adapting social patterns individually” (Szlendak, 2011a, p. 219).

It seems justified to analyze the motives behind infidelity, as well as the social functioning of men and women in the context of infidelity, from the perspective of gender. The concept of socio-cultural gender, as noted by Anna Titkow, reveals the meaning and spectrum of differences between women and men, which constitute their status and the rules defining the relationships among them in a given culture. It allows for a closer look at their “struggle” and the cognitive dissonances which they have to deal with (Titkow, 2011, p. 32). From this point of view, if one wants to address the question of the motives behind infidelity in a given society, they should trace the cultural determinants of femininity and masculinity, the social attitudes towards sexuality, as well as the entire set of relationships between the private life and the social structure (Szlendak, 2002, p. 140).

Why are we unfaithful? Of course, we can agree with the common stereotype stating that “men want only sex, while women want love.” Still, one might ask if it is actually true and whether it entails that women do not want sex. Nowadays, both women and men seek sexual pleasure to the same extent, as they perceive it as a basic component of their lives and relationships (Giddens, 2007, p. 85). When a relationship does not provide satisfaction in this regard, sexual needs will be fulfilled outside of it. The need for sexual fulfillment and pleasure is becoming increasingly important in the context of building a reflexive project of self. Sex bears, for men and women alike, a great promise of intimacy, something which—as Anthony Giddens puts it—touches upon the crucial aspect of the “self”. Nevertheless, considering their different starting points, implications of that fact are different for either sex (Giddens, 2007, p. 98–99). That is why in the case of adultery men and women will act—to quote Arlie Hochschils—in accordance with “gender strategies” (Turner & Stes, 2009, p. 57), so as to alleviate negative emotions triggered by the former. All of that for the sake of exciting experiences.

In consequence, engagement in any kind of sexual activity nowadays is related to the individual pursuit of pleasure. The fact that women and men in the modern world engage in “family oriented” activities originates from their egocentric and hedonistic impulses. According to Tomasz Szlendak, the contemporary times are governed by “the logic of individual autonomy” (Szlendak, 2011a, p. 226). As a result, if we are not able to fulfill our erotic and emotional needs within the family, we get involved in affairs. Men betray more often because they are licensed to do so by the pervasive male supremacy. Male infidelity is socially acceptable. Women betray their partners equally often, although they do not admit it—this results from the social expectations.

Results from this study indicate that marijuana use is not a reliable gateway cause of illicit drug use; as such, prohibition policies are unlikely to reduce illicit drug use

Is marijuana really a gateway drug? A nationally representative test of the marijuana gateway hypothesis using a propensity score matching design. Cody Jorgensen & Jessica Wells. Journal of Experimental Criminology, Apr 6 2021. https://rd.springer.com/article/10.1007/s11292-021-09464-z

Abstract: Marijuana use has been proposed to serve as a “gateway” that increases the likelihood that users will engage in subsequent use of harder and more harmful substances, known as the marijuana gateway hypothesis (MGH). The current study refines and extends the literature on the MGH by testing the hypothesis using rigorous quasi-experimental, propensity score-matching methodology in a nationally representative sample. Using three waves of data from the National Longitudinal Study of Adolescent to Adult Health (1994–2002), eighteen propensity score-matching tests of the marijuana gateway hypothesis were conducted. Six of the eighteen tests were statistically significant; however, only three were substantively meaningful. These three tests found weak effects of frequent marijuana use on illicit drug use but they were also sensitive to hidden bias. Results from this study indicate that marijuana use is not a reliable gateway cause of illicit drug use. As such, prohibition policies are unlikely to reduce illicit drug use.

Found a significant, negative relationship between resting metabolic rate and Extraversion; less extraverted individuals had a 30% higher RMR than the most extraverted ones; seems an allocation energy trade-off

Bergeron P, Pagé A, Trempe M (2021) Integrating humans into pace-of-life studies: The Big Five personality traits and metabolic rate in young adults. PLoS ONE 16(4): e0248876. doi:10.1371/journal.pone.0248876

Abstract: The pace-of-life syndrome (POLS) predicts that personality and metabolism should be correlated if they function as an integrated unit along a slow-fast continuum. Over the last decade, this conceptual framework has been tested in several empirical studies over a wide array of non-human animal taxa, across multiple personality traits and using standardized measures of metabolism. However, studies associating metabolic rate and personality in humans have been surprisingly scarce. Here, we tested whether there was covariation among personality scores, measured using the Big Five Inventory test, resting metabolic rate (RMR) and preferred walking speed (PWS) in a cohort of young human adults aged between 18 and 27 years old. We found a significant, negative relationship between RMR and Extraversion; less extraverted individuals had a 30% higher RMR than the most extraverted ones. No other personality traits correlated with RMR and none correlated with PWS. The negative correlation between Extraversion and RMR may suggest an allocation energy trade-off between personality and basal metabolism. Our results yielded equivocal support for the POLS and emphasized the need for more research on human to test the generality of this conceptual framework and further assess its validity.

Discussion

Our goal was to examine the correlations between the Big Five personality traits and metabolism in young adults. This research was inspired by the vast literature on the POLS using non-human animals, with the hope that standardized personality traits could contribute to reducing the measurement noise around this construct [7]. Our main result was that Extraversion correlated negatively with RMR. All other traits showed no correlations with RMR, and none of the traits was correlated with PWS.

While never reported before, the significant correlation between Extraversion and RMR is coherent with previous personality work. According to DeYoung’s cybernetic model [14], Extraversion and Openness share a common variance and can be regrouped under the metatrait Plasticity, which indicates one’s “tendency toward behavioral exploration, using motor output to pursue potentially rewarding possibilities […]”. In addition, when assessed using the 44-item Big Five Inventory test (as in the present study), Extraversion included several questions pertaining to the facet Activity [26]. This language is strikingly similar to that used in animal studies, in which “activity” and “exploration” scores are personality traits that have been shown to covary with metabolism [3]. In fact, when used in animal studies, “personality” cannot be dissociated from behavior since observing the animal’s behavior is the only way in which researchers can infer the animal’s personality [27]. It therefore may not come as a surprise if, in our dataset, the only significant correlation between RMR and personality was obtained with Extraversion, the trait highest in visibility and the one that can be most accurately assessed by other raters [28]. Thus, our results suggest that the components of personality linked to behavior and movements are attuned to the body metabolism.

The negative correlation between RMR and Extraversion, however, adds to a growing number of reports failing to support the POLS [7]. More specifically, the POLS would predict that personalities associated with energy-demanding behaviors should positively correlate with basal energy expenditure and not the opposite [3]. In contrast, Careau et al. [29] suggested that a negative correlation between personality and metabolism could be observed if “fast” personalities are maintained via an energetic allocation trade-off with metabolism. In other words, individuals could be able to sustain energetically demanding personalities (or the behaviors associated with these personalities) by spending less energy at rest. Such a trade-off has been observed between metabolic rate and boldness in fall field crickets (Gryllus pennsylvanicus) [30] and with activity in mosquito fish (Gambusia holbrooki) [31]. In humans, there have been suggestions that total daily energy expenditure is bounded to a fixed level such that an increase in daily energy expenditure (e.g., by engaging in physical activity) is associated with a corresponding decrease in basal energy expenditure [32]. Our results support the energy trade-off model and suggest that the energy cost associated with Extraversion (and, indirectly, the metatrait Plasticity) are compensated for by a decrease in basal metabolic rate. This conclusion is also coherent with Terracciano et al.’s observation that individuals who scored high on Extraversion saved energy by increasing their walking efficiency [23]. Whether individuals can energetically “afford” to be extraverted because of their metabolism or whether metabolism adapts to sustain the energetically demanding behaviors of some personality traits remains open for investigation.

The finding that Agreeableness, Conscientiousness, Neuroticism and, to a certain extent, Openness were not correlated with RMR can be interpreted in different ways. First, because these traits mainly encompass facets related to internal thoughts and affective states, it is possible that they vary independently from metabolism. However, we cannot exclude the possibility that a relationship does exist, but we were unable to capture it. As demonstrated before, these traits are higher in evaluativeness compared to Extraversion, indicating that social norms and values can influence how one responds to their associated questions [28]. Since our experiment was conducted on a small and intimate university campus, it is possible our participants’ responses were, intentionally or unintentionally, biased. This possibility could explain the rather low Cronbach’s alpha that we reported for these traits. In our context, an other-rater procedure may have led to a more accurate evaluation. Alternatively, our analysis may have been underpowered to detect a relationship of this size, making a larger sample size more desirable in future studies. Considered together, our results demonstrate the importance of further exploring the energetic costs of personality traits and their possible variations over the full life span.

The failure to observe a relationship between personality and PWS on a treadmill is difficult to interpret because the participants’ familiarity with this equipment was not homogenous in our sample. Future studies may want to utilize a more ecological measurement, such as the average walking speed over a 24-hour period assessed using a GPS or smartphone. In addition, the correlative nature of this research, using a single point measurement per subject and small sample size, requires caution in inferring causality since our approach does not allow for distinguishing among- and inter-individual contributions to the observed phenotypic correlation [33]. Additionally, we cannot exclude the possibility that a third, unmeasured trait affects the observed phenotypic correlation. For instance, ethnicity and time since last exercise could have been relevant control variables [22]. Nevertheless, our results raise important questions about the expected relationship between personality and metabolism within the POLS conceptual framework and highlight the importance of better understanding models of energy allocation. 

It is difficult for people to be persuaded by competing media accounts during a contentious election campaign; the real consequence of online partisan media may be an erosion of trust in mainstream news

The consequences of online partisan media. Andrew M. Guess et al. Proceedings of the National Academy of Sciences, April 6, 2021 118 (14) e2013464118; https://doi.org/10.1073/pnas.2013464118

Significance: Popular wisdom suggests that the internet plays a major role in influencing people’s attitudes and behaviors related to politics, such as by providing slanted sources of information. Yet evidence for this proposition is elusive due to methodological difficulties and the multifaceted nature of online media effects. This study breaks ground by demonstrating a nudge-like approach for exploring these effects through a combination of real-world experimentation and computational social science techniques. The results confirm that it is difficult for people to be persuaded by competing media accounts during a contentious election campaign. At the same time, data from a longer time span suggest that the real consequence of online partisan media may be an erosion of trust in mainstream news.

Abstract: What role do ideologically extreme media play in the polarization of society? Here we report results from a randomized longitudinal field experiment embedded in a nationally representative online panel survey (N = 1,037) in which participants were incentivized to change their browser default settings and social media following patterns, boosting the likelihood of encountering news with either a left-leaning (HuffPost) or right-leaning (Fox News) slant during the 2018 US midterm election campaign. Data on ≈ 19 million web visits by respondents indicate that resulting changes in news consumption persisted for at least 8 wk. Greater exposure to partisan news can cause immediate but short-lived increases in website visits and knowledge of recent events. After adjusting for multiple comparisons, however, we find little evidence of a direct impact on opinions or affect. Still, results from later survey waves suggest that both treatments produce a lasting and meaningful decrease in trust in the mainstream media up to 1 y later. Consistent with the minimal-effects tradition, direct consequences of online partisan media are limited, although our findings raise questions about the possibility of subtle, cumulative dynamics. The combination of experimentation and computational social science techniques illustrates a powerful approach for studying the long-term consequences of exposure to partisan news.

Keywords: mediapoliticspolarizationcomputational social science

Brain shape shares significant signal w/most neuropsych traits, as well as all behavioral– cognitive and subcortical volume traits; in contrast, face shape does not show significant sharing with any neuropsych disorders or behavioral–cognitive traits

Shared heritability of human face and brain shape. Sahin Naqvi, Yoeri Sleyp, Hanne Hoskens, Karlijne Indencleef, Jeffrey P. Spence, Rose Bruffaerts, Ahmed Radwan, Ryan J. Eller, Stephen Richmond, Mark D. Shriver, John R. Shaffer, Seth M. Weinberg, Susan Walsh, James Thompson, Jonathan K. Pritchard, Stefan Sunaert, Hilde Peeters, Joanna Wysocka & Peter Claes. Nature Genetics, Apr 5 2021. https://www.nature.com/articles/s41588-021-00827-w

Abstract: Evidence from model organisms and clinical genetics suggests coordination between the developing brain and face, but the role of this link in common genetic variation remains unknown. We performed a multivariate genome-wide association study of cortical surface morphology in 19,644 individuals of European ancestry, identifying 472 genomic loci influencing brain shape, of which 76 are also linked to face shape. Shared loci include transcription factors involved in craniofacial development, as well as members of signaling pathways implicated in brain–face cross-talk. Brain shape heritability is equivalently enriched near regulatory regions active in either forebrain organoids or facial progenitors. However, we do not detect significant overlap between shared brain–face genome-wide association study signals and variants affecting behavioral–cognitive traits. These results suggest that early in embryogenesis, the face and brain mutually shape each other through both structural effects and paracrine signaling, but this interplay may not impact later brain development associated with cognitive function.