Do Newborns Have the Ability to Imitate? We can now rule out some long-standing explanations for why the effect might be difficult to detect, only some research groups observe it, the published literature is biased

Do Newborns Have the Ability to Imitate? Virginia Slaughter. Trends in Cognitive Sciences, Vol 25, Issue 5, pp 377-387, March 13, 2021. https://doi.org/10.1016/j.tics.2021.02.006

Highlights

Although many assume that newborn infants imitate others, new data and analyses suggest it is not a reliable effect.

Meta-analysis of human neonatal imitation studies revealed an overall positive effect which was not moderated by major methodological variations, but did vary by research group.

Future studies of newborn imitation should adopt modern procedures to eliminate potential biases.

Researchers should also test models of how imitation could be learned. Associative Sequence Learning proposes that coincident experience of producing and perceiving body gestures over the first year of life, creates mirror systems to support imitation.

Neonatal imitation is widely accepted as fact and cited as evidence of an inborn mirror neuron system that underpins human social behaviour, even though its existence has been debated for decades. The possibility that newborns do not imitate was reinvigorated recently by powerful longitudinal data and novel analyses. Although the evidence is still mixed, recent research progresses the debate by ruling out some long-standing explanations for why the effect might be difficult to detect, by showing that only some research groups observe it, and by revealing indications that the published literature is biased. Further advances will be made with updated testing procedures and reporting standards, and investigation of new research questions such as how infants could learn to imitate.

Concluding Remarks

When considering all the evidence, it is hard to maintain the conviction that newborns imitate. However, there is still no definitive answer to the question. To find an answer, several things need to happen. Researchers should replace the 40-year-old methodology that has nurtured this controversy with modern approaches to data collection, analysis and reporting. It is also time to ask new questions: are newborns physically capable of imitating (Box 2)? To what extent do adults imitate babies in everyday interactions? Can imitation be trained in the first months of life? It also would be helpful if authors writing about newborns, imitation or mirror neurons, acknowledged the ongoing controversy rather than treating neonatal imitation as a fact.

Box 2

Do Newborns Have Voluntary Control of Oral–Facial Movements?

Putting aside the controversial evidence for and against newborn imitation, Keven and Akins [

57.

] considered whether newborn infants’ sensory–motor and brain development enables imitation. Their detailed analysis drawing on modern accounts of early neuromotor development suggested that imitation of mouth gestures, and tongue protrusion in particular, is beyond the capacity of neonates whose nervous systems are still adapting to postpartum life. It takes months for the newborn brain to coordinate breathing with sucking and swallowing liquids. As these functions mature, newborns engage in repetitive oral activity, including a lot of mouth opening and closing, and tongue protrusion and retraction. These patterned behaviours are involuntary, driven by subcortical brain mechanisms, and increase when newborns are aroused.

Keven and Akins’ analysis suggests that voluntary production of oral–facial movements in response to a matching model is physically impossible in newborns, because these gestures are generated by the brain’s subcortex in the first months of life. This would mean that so-called imitation in the newborn period is simply coincidental, since neonates’ involuntary mouth movements increase in response to the arousing sight of an experimenter’s animated face. This conclusion has been offered previously, based on observations that newborns increase their tongue protrusions in response to various arousing stimuli including light displays and orchestral music [

6.

]. Keven and Akins’ analysis also addresses the claim that newborn imitation fades out around 2–3 months of age: at that stage, the ‘wiring up’ of sucking, swallowing, and respiration functions are complete, so infants no longer involuntarily produce oral–facial movements in response to arousing stimuli.

Keven and Akins’ analysis demonstrates the value of asking different questions in relation to newborn imitation, rather than just focusing on ‘do they, or don’t they?’ However, their analysis was itself controversial, as evident in the open peer commentaries accompanying their article. For instance, some commentators dismissed the analysis as irrelevant to newborn imitation, relying on claims that a range of facial and manual gestures, in addition to tongue protrusion and mouth opening, are imitated by neonates [

58.

,

59.

]. Others accepted that newborns’ oral–facial movements promote maturation of sucking and swallowing but argued that they simultaneously function as communicative signals in face-to-face interactions with caregivers [

60.

,

61.

].

There is no doubt that imitation is a central element of human development. Indeed, there is a vast literature documenting what children imitate, from whom, and under what circumstances [

55.

]. However, we still do not know when or how this ubiquitous behaviour emerges, which means that we do not truly understand it (see Outstanding Questions). If imitation turns out to be learned rather than inborn, this would not diminish the theoretical significance of imitation for infant–parent bonding, social learning or later-developing interpersonal skills. Rather, it would highlight the brain’s proclivity to create connections between ourselves and others, from the first months of life.

Outstanding Questions

Is there evidence of imitation when newborns are tested with objective measures such as EMG?

Does video modelling of gestures genuinely increase newborns’ imitative response as suggested by the meta-analysis? If so, why?

What accounts for the meta-analytic finding that neonatal imitation varies by research group?

How frequently do infants experience observation–action correspondences during a typical day and is this variable related to production of imitation?

Are different types of observation–action correspondence (e.g., self-observation, mirror exposure, and caregiver mimicry) related to different forms of imitation in infancy?

Can imitation be promoted in infants with observation-action training as predicted by ASL?

Delinquency: Substantial genetic origin for those of persistently bad or aggresive behaviour (heritability = 67%), whereas genetic influences were negligible for lower-risk subgroups

Developmental Trajectories of Delinquent and Aggressive Behavior: Evidence for Differential Heritability. Joshua Isen, Catherine Tuvblad, Diana Younan, Marissa Ericson, Adrian Raine & Laura A. Baker. Child Psychiatry & Human Development, Jan 15 2021. https://link.springer.com/article/10.1007/s10578-020-01119-w

Abstract: The developmental course of antisocial behavior is often described in terms of qualitatively distinct trajectories. However, the genetic etiology of various trajectories is not well understood. We examined heterogeneity in the development of delinquent and aggressive behavior in 1532 twin youth using four waves of data collection, spanning ages 9–10 to 16–18. A latent class growth analysis was used to uncover relevant subgroups. For delinquent behavior, three latent classes emerged: Non-Delinquent, Low-Level Delinquent, and Persistent Delinquent. Liability for persistent delinquency had a substantial genetic origin (heritability = 67%), whereas genetic influences were negligible for lower-risk subgroups. Three classes of aggressive behavior were identified: Non-Aggressive, Moderate, and High. Moderate heritability spanned the entire continuum of risk for aggressive behavior. Thus, there are differences between aggressive behavior and non-aggressive delinquency with respect to heterogeneity of etiology. We conclude that persistent delinquency represents an etiologically distinct class of rule-breaking with strong genetic roots.

Reaping a benefit at the expense of multiple others: We make more selfish choices, and judge others’ selfish choices more lightly, when the social losses are dispersed more thinly across a group

Reaping a benefit at the expense of multiple others: How are the losses of others counted? Meir Barneron, Shoham Choshen-Hillel, Ilan Yaniv. Organizational Behavior and Human Decision Processes, Volume 164, May 2021, Pages 136-146. https://doi.org/10.1016/j.obhdp.2021.02.004

Highlights

• We studied selfish choices that create social loss, harming the welfare of others.

• We theorized that empathy underlies perceptions of the harm caused to others.

• Participants should be sensitive to the individual harm, not to the aggregate harm.

• Our studies supported these predictions and revealed a dispersion effect.

• Rated feelings of empathy mediated the participants’ judgments of selfish decisions.

Abstract: We investigate individual decisions that produce gains for oneself, while imposing losses on a group of others. We theorize, based on the notion of empathy, that decision-makers consider the magnitude of the pain or loss they inflict on an individual in the group, but are largely insensitive to the number of individuals in the group who suffer losses. Studies involving personal choices or judgments of others’ choices largely confirmed these predictions. They also revealed a dispersion effect, whereby participants made more selfish choices, and judged others’ selfish choices more lightly, when the social losses were dispersed more thinly across a group. It appears that decision-makers’ empathy for others who suffer losses is not readily adjusted to the number of people affected or to the aggregated losses. It also appears that empathy mediates judgments of selfish behavior. The findings are related to theories of empathy, and decisions under conflicts of interest.

Keywords: Judgment and decision makingSelfish vs prosocial behaviorEmpathySocial preferenceConflict of interestDecision ethics

People ascribe differing degrees of genetic influence to the same phenotype depending on whether it is expressed in socially favored or disfavored ways

Genetic attributions and perceptions of naturalness are shaped by evaluative valence. Matthew S. Lebowitz, Kathryn Tabb & Paul S. Appelbaum. The Journal of Social Psychology, Apr 9 2021. https://doi.org/10.1080/00224545.2021.1909522

Abstract: Genetic influences on human behavior are increasingly well understood, but laypeople may endorse genetic attributions selectively; e.g., they appear to make stronger genetic attributions for prosocial than for antisocial behavior. We explored whether this could be accounted for by the relationship of genetic attributions to perceptions of naturalness. Participants read about positively or negatively valenced traits or behaviors and rated naturalness and genetic causation. Positively valenced phenotypes were rated significantly more natural and significantly more genetically influenced than negatively valenced phenotypes, and the former asymmetry significantly mediated the latter (Experiments 1 and 2). Participants’ interpretation of what “natural” meant was not synonymous with valence or genetic attributions (Experiment 3). People ascribe differing degrees of genetic influence to the same phenotype depending on whether it is expressed in socially favored or disfavored ways, potentially representing a significant threat to public understanding of genetics.

KEYWORDS: Geneticssocial cognitioncausal attributionmotivated reasoning

Check also Antisocial behaviour was consistently rated as less genetically influenced than prosocial behaviour; asymmetry may stem from people’s motivating desire to hold wrongdoers responsible for their actions:

Asymmetrical genetic attributions for prosocial versus antisocial behaviour. Matthew S. Lebowitz, Kathryn Tabb & Paul S. Appelbaum. Nature Human Behaviour, volume 3, pages 940–949 (2019), July 29 2019. https://www.bipartisanalliance.com/2019/09/antisocial-behaviour-was-consistently.html

In all, results suggest that the relationships between physical activity, mental health, and well-being are tenuous, at best

Klussman, K., Langer, J., & Nichols, A. L. (2021). The relationship between physical activity, health, and well-being: Type of exercise and self-connection as moderators. European Journal of Health Psychology, Apr 2021. https://doi.org/10.1027/2512-8442/a000070

Rolf Degen's take: https://twitter.com/DegenRolf/status/1380794815277850624

Abstract

Background: Most people are comfortable asserting the beneficial effects of physical exercise on mental health and well-being. However, little research has examined how different types of physical activity affect these outcomes.

Aims: The current study sought to provide a comprehensive understanding of the differential relationships between different types of physical activity and various aspects of health and well-being. In addition, we sought to understand the role of self-connection in these relationships. Method: One hundred forty-three participants completed a questionnaire designed to measure their current weekly activity as well as their current health and well-being. Specifically, we examined three intensities of activity (walking, moderate, and vigorous) and three types of activity (team-based, community-based, and not team nor community-based) on self-reported health, anxiety, depression, affect, flourishing, job satisfaction, life satisfaction, and meaning in life. In addition, we examined self-connection as a possible moderator of these relationships.

Results: Results suggested that physical activity was inconsistently related to health and well-being, and activity intensity and type were important to understanding these relationships. In contrast, self-connection reliably related to health and well-being and moderated the relationship between activity type and the presence of meaning.

Limitations: The cross-sectional, self-report nature of the study limits its contribution. In addition, we only examined a subset of all physical activities that people engage in.

Conclusion: In all, results suggest that the relationships between physical activity, mental health, and well-being are tenuous, at best. Future research needs to examine these relationships further and continue to examine self-connection to determine how to best increase health and well-being through physical activity. 

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.