Tuesday, January 11, 2022

Judgments About Male Victims of Sexual Assault: 2019 female cohort more likely to attribute encouragement to victim (27% in 2019 vs 4% in 1984) & to believe that the victim derived pleasure or had less stress (25% vs 5%) than female victims

Judgments About Male Victims of Sexual Assault by Women: A 35-Year Replication Study. Emma K. PeConga, Jacqueline E. Spector, Ronald E. Smith. Journal of Interpersonal Violence, January 3, 2022. https://doi.org/10.1177/08862605211062990

Abstract: Sexual assault of men by women has received increasing attention in recent years, as has research on rape myths about male victims. This study is a cross-generational replication of a 1984 study of college students’ judgments about male and female victims in a scenario involving a sexual assault carried out by male or female assailants. The 1984 data (n = 172) were compared with those of a 2019 cohort (n = 372) in a 2 (participant gender) x 2 (assailant gender) x 2 (victim gender) x 2 (cohort) factorial design to assess potential generational changes in perceptions of victims. Judgments by male participants of male victims of assaults carried out by women changed notably over time. The 2019 male cohort was less likely to judge that the victim initiated or encouraged the incident (40% in 1984 compared with 15% in 2019) and derived pleasure from it (47.4% in 1984 compared with 5.8% in 2019). In contrast, the 2019 female cohort was more likely to attribute victim encouragement (26.9% compared with 4.3% in 1984) and pleasure to the male victim (25% in 2019 compared with 5% in 1984). A similar gender pattern occurred in judgments of how stressful the event was for the male victim. Analysis of the 2019 data revealed that overall, despite scientific and cultural shifts that have occurred over the past three decades, participants continued to judge the male victim of assault by a female to have been more encouraging and to have experienced more pleasure and less stress than in any other assailant/victim gender combination. Results are discussed in relation to gendered stereotypical beliefs and male rape myths, as well as possible sensitization to power differentials inspired by the #MeToo movement. We emphasize the need for greater awareness and empirical attention to abuse that runs counter to preconceived notions about sexual victimization.

Keywords: rape, sexual assault, rape myths, male victimization, gender

Vascular and blood-brain barrier-related changes underlie stress responses and resilience in female mice and depression in human tissue

Vascular and blood-brain barrier-related changes underlie stress responses and resilience in female mice and depression in human tissue. Laurence Dion-Albert, Alice Cadoret, Ellen Doney, Fernanda Neutzling Kaufmann, Katarzyna A. Dudek, Beatrice Daigle, Lyonna F. Parise, Flurin Cathomas, Nalia Samba, Natalie Hudson, Manon Lebel, Signature Consortium, Matthew Campbell, Gustavo Turecki, Naguib Mechawar & Caroline Menard. Nature Communications volume 13, Article number: 164. Jan 10 2022. https://www.nature.com/articles/s41467-021-27604-x

Abstract: Prevalence, symptoms, and treatment of depression suggest that major depressive disorders (MDD) present sex differences. Social stress-induced neurovascular pathology is associated with depressive symptoms in male mice; however, this association is unclear in females. Here, we report that chronic social and subchronic variable stress promotes blood-brain barrier (BBB) alterations in mood-related brain regions of female mice. Targeted disruption of the BBB in the female prefrontal cortex (PFC) induces anxiety- and depression-like behaviours. By comparing the endothelium cell-specific transcriptomic profiling of the mouse male and female PFC, we identify several pathways and genes involved in maladaptive stress responses and resilience to stress. Furthermore, we confirm that the BBB in the PFC of stressed female mice is leaky. Then, we identify circulating vascular biomarkers of chronic stress, such as soluble E-selectin. Similar changes in circulating soluble E-selectin, BBB gene expression and morphology can be found in blood serum and postmortem brain samples from women diagnosed with MDD. Altogether, we propose that BBB dysfunction plays an important role in modulating stress responses in female mice and possibly MDD.


Only a handful of studies have explored BBB sex differences, most indirectly and in vitro37 but, to our knowledge, none did so in the context of chronic stress in mice or MDD. Overall, our findings indicate that chronic social and subchronic variable stressors alter BBB integrity in the mouse female brain through loss of the tight junction protein Cldn5 in the PFC and, to some extent, other mood-related brain regions such as the NAc. Importantly, these vascular alterations are also present in postmortem human brain samples from women with MDD. In mice, viral-mediated downregulation of Cldn5 in the PFC is sufficient to promote anxiety- and depression-like behaviours including social avoidance, anhedonia, and helplessness supporting a causal role in the establishment of maladaptive stress responses and possibly, mood disorders. We did not observe stress-induced BBB dysfunction in the male PFC7 indicating that chronic stress and depression affect the neurovasculature in a sex-specific manner. Different stress paradigms elicit specific anxiety- and depression-like behaviours according to sex, each recapitulating certain aspects of the symptoms and molecular features of MDD38.

A potential limitation of the female CSDS model we have used here is exposure to a male stressor (i.e., antagonistic social confrontations by a larger male aggressor). In male C57BL/6, the CSDS paradigm has been shown to have relevant etiological, predictive and face validity14. However, additional studies are warranted to confirm that this model is also etiologically relevant for female mice. Furthermore, SI tests were conducted using a male social target and we cannot exclude a possible confounding effect of intersex social interaction on the SI ratio values. Performing these tests with a female target may result in a different stratification of SS and RES mice, as we report for our virus-injected cohorts. We chose to use male mice as social targets in other contexts because social stress was performed by male aggressors19. Physical injuries are always a concern when running the CSDS paradigm either in males or females. Indeed, sickness behaviours could account for behavioral changes through stimulation of the immune system and entry of inflammatory mediators into the brain via altered BBB permeability. Therefore, physical examinations of animals were performed and no difference in the number of wounds was observed (Supplementary Figs. 1a and 8b) suggesting that susceptible vs resilient behavioral phenotypes were not due to physical injury. Finally, stress resilience is a fluid concept, and it is still debated whether or not it can be defined as a trait39. The complex neurobiological interactions underlying SS and RES phenotypes are not fully understood and are highly context-dependent. Coping strategies (i.e., social interactions) may be considered adaptative in some circumstances and maladaptive in others, and such mechanisms have been poorly investigated in females40. Thus, further studies are needed to better understand individual differences in stress-induced resilience vs vulnerability and how these behavioural responses and underlying mechanisms relate to human mood disorders.

Only females are susceptible to 6-d SCVS; however, both sexes display depression-like behaviours after weeks of stress exposure915 or if behavioural testing is performed 30 days after the 6-d SCVS paradigm41. Discrepancies in these behaviours could explain the sex-specific regional vascular effects observed and, possibly, sex differences associated with MDD. Magnetic resonance imaging (MRI) studies also support this idea, with unmedicated women with MDD showing decreased grey matter volume in limbic regions, including the left ventral PFC, while this reduction is observed in striatal regions for men with MDD42. Our study is also in line with recent clinical observations reporting region-specific BBB disruption in psychiatric disorders4344, although sex differences were not addressed.

Our work not only highlights fundamental sex differences in stress-induced neurovascular responses but also provides mechanistic insights by identifying key pathways and genes involved. Bulk tissue sequencing studies show a major rearrangement of transcriptional patterns in mood-related brain regions in MDD with low overlap between men vs women with MDD (~10%)911. These marked sex differences are also observed in mouse models of depression915. Neuronal contribution is undeniable, notably via changes in neurotransmitter systems9. Nevertheless, a significant enrichment for endothelium-related genes is also present9 but had never been explored. Bulk RNA sequencing revealed a similar enrichment for genes related to this cell population in schizophrenia45, reinforcing the involvement of the neurovasculature in psychiatric disorders. Although the resilience phenotype in female mice is not as clearly defined as it is for their male counterparts when analysing behaviours1924, our endothelium transcriptomic profiling revealed a distinct resilience-associated pattern when compared to animals displaying anxiety- or depression-like behaviours induced by either chronic social or subchronic variable stress. We found secreted enzyme phospholipase A2 Group VII (Pla2g7) as a gene significantly upregulated in SS vs RES mice, and Pla2g7 methylation is associated with increased risk of coronary heart disease specifically in women46. On the other hand, carnitine acyl carnine translocase (Slc25a20) is decreased in the PFC of SS females when compared to RES, which is consistent with previous studies reporting decreased acetyl-l-carnitine in MDD patients47.

Interestingly, both sexes show significant endothelium gene expression changes in the omega-3/omega-6 fatty acid synthesis pathways in the PFC following chronic social stress. However, these alterations were observed in RES vs CTRL for females and between SS vs CTRL in males. This pathway has been extensively studied in human depression as well as in animal models of mood disorders with omega-3 deficiency linked to neuronal atrophy in the medial PFC of male mice, concomitant with anxiety- and depressive-like behaviours48. Fatty acids play an important role in the regulation of systemic49 and endothelium inflammation50, thus providing an intriguing association between depression-related disruptions in the neuroimmune axis51 and BBB hyperpermeability. Similarities between the PFC female resilient and male susceptible endothelial transcriptome profiles for this pathway and the fact that both subgroups maintain BBB integrity in this brain region despite chronic stress exposure suggest that it could play a protective role in stress-induced BBB permeability loss. With previous reports linking omega-3 fatty acid consumption with resilience to stress in rodents52 and humans53, further studies are warranted to confirm their potential beneficial effect on the neurovasculature and gain mechanistic insights.

A possible mechanism for this sex- and region-specific vulnerability of the BBB is the presence of estrogen receptors on the neurovasculature. Endothelial cells express low levels of functional estrogen receptors54 and estrogen-coupled receptors can enter the cell nucleus and bind to estrogen-responsive elements (ERE) on specific DNA sequences55. Interestingly, ERE and stimulating protein 1 (Sp1) transcription factors were identified on the mouse Cldn5 gene promoter, which allows estrogen receptors to modulate Cldn5 transcription through cooperative interactions of Er/Sp1 with ERE/Sp1 elements56. While high levels of estrogen render female rats more sensitive to stress-induced PFC dysfunction57, this was found to be protective in the striatum58, providing mechanisms to explore for future studies. Our group has recently shown that permissive epigenetic regulation of Cldn5 expression paired with low endothelium Cldn5-repressive transcription factor forkhead box protein O1 is associated with stress resilience in the NAc of male mice, while increased histone deacetylase 1 level and activity is a mediator of stress susceptibility8. Thus, investigating sex-specific epigenetic vascular mechanisms underlying susceptibility vs resilience to stress and BBB hyperpermeability will be important in the future.

Additionally, estrogen-activated receptors have been shown to inhibit the proinflammatory transcription factor NfkB (nuclear factor kappa light chain enhancer of activated B cells), a known regulator of ICAM-1 and E-selectin59. Increased circulating proinflammatory cytokines and NFkB were reported in adolescent MDD and bipolar disorder, correlated with depressive symptoms severity60, and we have identified the proinflammatory NFkB pathway as a mediator of stress susceptibility in NAc endothelial cells of male8 but not female mice (Figs. 4 and 5). Accordingly, we observed a sex-specific increase in circulating sICAM-1 levels only in SS male mice vs pre-CSDS at baseline (Supplementary Fig. 10) and Icam1 levels are increased in the NAc of SS male mice8 but seem to be reduced in the PFC of SS female mice (Supplementary Fig. 10), reinforcing the idea of sex-specific regulatory mechanisms of BBB integrity, possibly through estrogen-mediated pathways. Social defeat stress increases the expression of adhesion molecules in the male mouse brain, including Icam-1 and Sele the gene encoding for E-selectin61. We did observe a trend, that did not reach significance, for higher expression of Sele in the PFC of stressed mice (Supplementary Fig. 10) suggesting that the increase in circulating sE-selectin measured in the blood serum of SS females may come, at least partly, from other brain regions or non-CNS sources. Moreover, elevated blood sE-selectin level was reported in the elderly with mild cognitive impairment and depressive mood62; however, these studies did not address sex differences. Assessment of BBB leakage using MRI scans in patients suffering from bipolar disorder allowed identification of a subpopulation of patients characterized by worse symptoms including the severity of depression, anxiety, chronicity of illness and decreased global functioning63. Despite being commonly used worldwide, it would be unrealistic to apply BBB imaging to a large population scale or in a preventive context highlighting the importance in discovering biomarkers of psychiatric diseases as we aimed to do here. It could be particularly relevant for conditions involving exacerbated inflammation and/or vascular dysfunction and for which MDD prevalence is higher than the general population; for example, stroke or Alzheimer’s disease1.

Many unanswered questions persist regarding BBB adaptations in both health and disease18. Our multidisciplinary approach allowed us to identify sex-specific circulating vascular potential biomarkers as well as candidate genes and pathways that could be relevant to inform on MDD diagnosis and develop treatments. Targeting and regulating tight junction protein integrity at the BBB level could represent an innovative strategy to treat mood disorders43. However, thinking beyond endothelial cells will be important to better understand the complex biology underlying BBB hyperpermeability in MDD. Single-cell sequencing of postmortem brain tissue from individuals with MDD shows important dysfunction in the PFC pyramidal neurons and oligodendrocyte-lineage cells64, but to our knowledge, this had never been investigated for endothelial cells, smooth muscle cells or pericytes. By characterizing sex- and region-specific neurovascular alterations underlying stress susceptibility in mice and human depression we provide valuable clues and highlight the need to consider sex as a biological variable while defining the role of brain barriers in psychiatric diseases. These findings are also important in the context of cardiovascular diseases (CVD), with evidence supporting a bidirectional relationship between depression and CVD, where depression is a predictor for the development of CVD, and vice versa65. Like in MDD, sex differences in age of onset, symptomatology and treatment response exist in CVD, highlighting the possibility of common etiological basis. Thus, investigating the candidate genes and circulating vascular potential biomarkers associated with depression we report here in populations of CVD patients would be highly relevant and could provide clues into shared underlying mechanisms of CVD and MDD pathologies. As an example, we observed an increase in sPAI-1, a prothrombotic plasma protein secreted by endothelial tissue, following social and subchronic variable stress in female, but not male, mice (Fig. 6c, d, Supplementary Fig. 10). Dysfunction of this pathway has been proposed as a link between MDD and CVD66 but underlying mechanisms remain to be elucidated. Genetic variants of the PAI-1 gene (SERPINE1) have been associated with MDD67. An elevated level of PAI-1 proteins is observed in the serum of individuals with major depression disorder68, but is also linked with increased risk of ischemic cardiovascular events such as thrombosis and atherosclerosis69. Antidepressant treatment decreases PAI-1 expression in the brain of male rats67. However, discrepancies exist with PAI-1 deficiency predisposing male mice to depression-like behaviours and resistance to commonly prescribed selective serotonin reuptake inhibitors70. Our findings suggest that PAI-1 may be even more relevant for female stress responses, and it was hypothesized that it could play a role in perinatal depression71, raising interest for future studies on this target to gain mechanistic insights particularly for female rodents and women with MDD.

To sum up, our study shows that chronic stress can induce BBB alterations in the female PFC promoting anxiety, depression-like behaviours, and BBB leakiness (Supplementary Fig. 11). Importantly, loss of tight junction CLDN5 expression was confirmed in postmortem brains samples from women with major depressive disorder supporting relevance for human MDD. These alterations were associated with changes in circulating vascular potential biomarkers in the mouse and human blood serum that will have to be explored in future clinical studies and larger human cohorts to confirm translational value. Conversely, despite chronic stress exposure, BBB integrity is maintained in the PFC of RES animals and this could be related to transcriptomic adaptations and activation of protective signalling pathways in the endothelium (Supplementary Fig. 11). Although this project explored neurovasculature-related changes in two brain regions, many other areas involved in emotion regulation remain unexplored and we hypothesize that stress-induced BBB changes go beyond the NAc and PFC. It will also be intriguing to investigate if age-related neurovascular changes such as BBB breakdown, which has been linked to human cognitive dysfunction72, play a causal role in late-life depression73 which is more prevalent in women74.

Roughly 40% of Americans state that they do not feel comfortable disclosing their views publicly, a roughly three-fold increase since the 1950's

Preference Falsification: How Social Conformity as an Interdependent, Recursive, and Multilevel Process Corrupts Public Knowledge. Jacob Elder, Yrian Derreumaux, Brent Hughes. Department of Psychology, University of California, Riverside, April 2021. DOI: 10.31234/osf.io/b2xkp

Description: Throughout life, people often misrepresent their preferences to maintain social harmony, yet the cumulative effects of individual acts of conformity on society are largely underexplored. This phenomenon is captured by the economic theoretical framework of Preference Falsification, which describes why people misrepresent their preferences in the face of social pressures, and how misrepresentation accumulates to broader misunderstandings that can fuel political polarization. We first describe why the current political climate may foster motivations to misrepresent preferences, as individuals are increasingly strongly identified with their political groups and siloed into like-minded communities with strong pressures to conform to group norms. Next, we adopt a psychological lens to understand Preference Falsification at different levels of analysis: (1) at the individual level, to examine how failures in cognitive empathy and statistical learning facilitate social conformity that gives rise to falsification, and (2) at the collective level, to examine how misrepresented preferences propagate across social relationships and structures. Our goal is to advance theory by demonstrating that Preference Falsification provides a generative framework that describes how various micro-level phenomena related to social influence can propagate across social structures and corrupt public knowledge. Ultimately, we argue that PF limits access to accurate and truthful information, which fuels misinformation and poses a barrier to social change.


If polarization-induced social pressures motivate people to self-censor or conform (Bar-Tal, 2017), this may contribute to collective misunderstandings and dissatisfaction with the status quo. In fact, people have more shared private preferences than what they perceive to be shared with others, producing an inflated impression of disagreement over specific issues (Ahler & Sood, 2018; Fiorina & Abrams, 2008; Waytz et al., 2019). Individual acts of conformity may propagate across individuals within a social structure, and consequently blur the lines between what people truly prefer and what people claim to prefer merely to conform. In turn, this corruption of public knowledge accumulates to exacerbate the very social pressures that initiated the individual acts of conformity in the first place. This phenomenon is described by the economic theoretical framework of Preference Falsification (PF), which describes what happens when people explicitly misrepresent their private preferences (i.e., what they truly prefer) due to perceived social pressures, such that people’s public preferences (i.e., what they express) are inconsistent with their private preferences (Kuran, 1997).

While psychological research has independently examined phenomena related to social conformity (e.g., impression management, social desirability bias, social influence), how people acquire and use social information (e.g., cognitive empathy, statistical learning), and other related phenomena, it has not yet integrated them to understand how individual acts of falsification can accumulate to corrupt publicly available information, and how this fuels collective misunderstanding. Here, we build on the theoretical framework of PF by synthesizing related areas of psychological research in order to understand the processes that underlie PF and how they propagate across social structures. We characterize PF as an interdependent, recursive, and multilevel process, by which acts of conformity by one individual may incentivize acts of conformity by other individuals (i.e. interdependent), which may lead to misinformation being expressed across individuals and social groups within a society (i.e. recursive), and ultimately manifest in a corruption of available information and widespread endorsement of unpopular positions (i.e. multilevel).

This framework produces several important predictions and implications: (1) PF predicts widespread public support for preferences that are otherwise privately unsupported by individuals (or vice versa: public opposition for preferences that are otherwise privately supported), which stifles potential change (Kuran, 1987). From this perspective, the status quo persists not only due to self-censorship, but also because people conform to the status quo out of fear of social repercussions (i.e., Preference Falsification). This may then discourage people from considering possible alternatives, as the status quo shapes people’s expectations of what is possible. Thus, although individuals may privately prefer outcomes different from the status quo, they may publicly express preferences that sustain it and in doing so stifle potential social change (i.e., collective conservatism; Kuran, 1987). (2) PF predicts larger differences in public preferences between groups, and smaller differences in public preferences within groups (Boyd & Richerson, 1985; Henrich & Boyd, 1998). This provides one mechanism for polarization that thereby increases the perceived costs of expressing preferences that deviate from one’s group (Kuran, 1997; also see Figure 1 for a theoretical representation of how PF can promote and sustain polarization). (3) PF predicts how dissent and honest expression among ostensibly minority groups can ignite unanticipated social movements, via the propagation of public preferences that were previously falsified (Kuran, 1998). Honest expression of private preferences can provide a shock to the social structure by changing societal pressures and exposing previously hidden dissent, such that the perceived costs to expressing particular public preferences become attenuated. Taken together, PF can help to explain how social and political policies that may not be representative of the population are upheld due to the perceived costs of deviating from group norms, and conversely, how individual dissenters can catalyze change by igniting social movements that reduce the social pressures to conform.

Men’s Sexual Interest in Feminine Trans Individuals across Cultures

Men’s Sexual Interest in Feminine Trans Individuals across Cultures. Lanna J. Petterson &Paul L. Vasey. The Journal of Sex Research, Jan 5 2022. https://doi.org/10.1080/00224499.2021.2013429

Abstract: Feminine trans individuals (i.e., individuals who were assigned male at birth but who have a feminine gender presentation and identity) are present in many cultures. In some cultures, these individuals identify as (trans) women. Many of these individuals undergo medical treatments to feminize their bodies (e.g., breast augmentation), but most do not undergo vaginoplasties and therefore have penises. In many non-Western cultures, feminine trans individuals identify as a non-binary gender (i.e., neither man, nor woman). Many of these individuals do not surgically augment their bodies. Across cultures, some men express sexual interest in feminine trans individuals. Are manifestations of sexual interest in feminine trans individuals consistent across Western and non-Western cultural settings? Our review suggests that, across cultures, most of these men are also sexually attracted to cisgender individuals. Many are sexually attracted to cisgender women or to cisgender members of both sexes. A small subset is sexually attracted to cisgender men. Men who are sexually interested in feminine trans individuals commonly report being primarily insertive during anal sex. Additionally, they tend to report that their sexual interest in these individuals is motivated by attraction to femininity or to the combination female- and male-typical characteristics.

Monday, January 10, 2022

Female dolphins possess a well-developed clitoris, which may very well have evolved as a sheer pleasure dispenser

Evidence of a functional clitoris in dolphins. Patricia L.R. Brennan, Jonathan R. Cowart, Dara N. Orbach. Current Biology, Volume 32, Issue 1, 10 January 2022, Pages R24-R26. https://doi.org/10.1016/j.cub.2021.11.020

Summary: In species that copulate during non-conceptive periods, such as humans and bonobos, sexual intercourse is known to be pleasurable for females. Dolphins also copulate throughout the year, largely to establish and maintain social bonds1. In dolphins, the clitoris is positioned in the anterior aspect of the vaginal entrance2, where physical contact and stimulation during copulation is likely. Clitoral stimulation seems to be important during female–female sexual interactions in common bottlenose dolphins (Tursiops truncatus), which rub each other’s clitorises using snouts, flippers, or flukes3. Determining a sexual pleasure response in animals not amenable to neurobehavioral examination is difficult, but investigation of the clitoris may elucidate evidence of functionality. In this study, we assessed macro- and micromorphological features of the clitoris in common bottlenose dolphins to examine functional features, including erectile bodies with lacunae, extensible collagen and/or elastin fibers, and the presence and location of sensory nerves. Our observations suggest the clitoris of dolphins has well-developed erectile spaces, is highly sensitive to tactile stimulation, and is likely functional.

US men and women both reported more conflict with mothers-in-law than with mothers, and mothers reported more conflict with their daughters-in-law than with their daughters

Mother-in-Law Daughter-in-Law Conflict: an Evolutionary Perspective and Report of Empirical Data from the USA. Jessica D. Ayers, Jaimie Arona Krems, Nicole Hess & Athena Aktipis. Evolutionary Psychological Science, Jan 10 2022. https://link.springer.com/article/10.1007/s40806-021-00312-x

Abstract: Relationships with genetic relatives have been extensively studied in the evolutionary social sciences, but affinal, i.e., in-laws, relationships have received much less attention. Yet, humans have extensive interactions with the kin of their mates, leading to many opportunities for cooperative and conflictual interactions with extended kinship networks. To contribute to the scholarship on affinal bonds, and particularly on perceptions of affinal conflict, we collected empirical data on cooperation and conflict among affines. Here, we report empirical evidence of self-reported cooperative and conflictual aspects in affinal relationships in a Western sample. US men and women both reported more conflict with mothers-in-law than with mothers, and mothers reported more conflict with their daughters-in-law than with their daughters. We discuss the implications of this work and directions for future research.

Dominance in humans is of great importance; it's separated from prestige—an alternate avenue to high status in which status arises from information (e.g. knowledge, skill, etc.) or other non-rival goods

Dominance in humans. Tian Chen Zeng, Joey T. Cheng and Joseph Henrich. Philosophical Transactions of the Royal Society B: Biological Sciences, January 10 2022. https://doi.org/10.1098/rstb.2020.0451

Abstract: Dominance captures behavioural patterns found in social hierarchies that arise from agonistic interactions in which some individuals coercively exploit their control over costs and benefits to extract deference from others, often through aggression, threats and/or intimidation. Accumulating evidence points to its importance in humans and its separation from prestige—an alternate avenue to high status in which status arises from information (e.g. knowledge, skill, etc.) or other non-rival goods. In this review, we provide an overview of the theoretical underpinnings of dominance as a concept within evolutionary biology, discuss the challenges of applying it to humans and consider alternative theoretical accounts which assert that dominance is relevant to understanding status in humans. We then review empirical evidence for its continued importance in human groups, including the effects of dominance—independently of prestige—on measurable outcomes such as social influence and reproductive fitness, evidence for specialized dominance psychology, and evidence for gender-specific effects. Finally, because human-specific factors such as norms and coalitions may place bounds on purely coercive status-attainment strategies, we end by considering key situations and contexts that increase the likelihood for dominance status to coexist alongside prestige status within the same individual, including how: (i) institutional power and authority tend to elicit dominance; (ii) dominance-enhancing traits can at times generate benefits for others (prestige); and (iii) certain dominance cues and ethology may lead to mis-attributions of prestige.

5. Discussion

The evidence reviewed above indicates that dominance continues to be a viable route to rank acquisition, impacting both social influence and fitness in humans across a wide range of contexts, and plays a role in human status asymmetries from the youngest of ages. However, the human-specific complications presented in this review cannot be overlooked. First, we comment on some important methodological and theoretical issues with research programmes that attempt to measure dominance in our species. Second, we look into gender-specific effects of dominant strategies for rank acquisition. Also finally, because norms may place bounds on the effectiveness of coercion-based strategies to rank attainment or even modify their function, we lay out the evidence for three social dynamics that influence dominance attainment and their interaction with prestige, and use concepts previously developed to consider how socioecological and institutional factors affect when and how dominant individuals can attain influence.

(a) Theoretical and methodological challenges

Because dominance produces status or influence over others' actions that is achieved against anothers' preferences, survey measures that tap the colloquial understanding of ‘social influence’ or ‘status' or that rely on the definition of status in social psychology (which involves gaining deference through changing another's preferences; [51]) may fail to capture the full impact of dominance. Indeed, a recent high-profile analysis of questionnaire responses [3] found across a range of large-scale societies, that people rated dominant traits (defined by ‘cost-infliction inclinations and abilities') to have weak or no impact on social influence after controlling for prestigious traits (benefit-provisioning inclinations and abilities). However, in several follow-up studies, Cheng et al. [147] demonstrated that the descriptors of the dependent variable (social influence) in the study strongly activated prestige-related concepts, which would make ‘prestige' appear more important in the results. Translations often magnified this problem by using synonyms for ‘reputation' and sometimes ‘prestige’ itself in the target language for the dependent variable. Additionally, the analyses suffered from high collinearity between dominance and prestige, which rendered any firm conclusions inappropriate. However, reanalyses designed to address this issue revealed an important role for dominance, albeit less than for prestige—which is not unexpected given the translation process and the semantics of words used for the dependent variable. For the reasons we have described, prestige may often be more important than dominance in many contexts, but as we have reviewed, dominance continues to play an important role.

Studies of non-human primates use multiple measures of dominance, such as resource control after competitive bouts, or directionality of aggression and formal dominance signals. These measures usually correlate, but not always, leading to doubts about construct validity in some species [148]. Nevertheless, recent research in humans that treats dominance as a trait reflecting stable individual differences in ability and tendency to use force-based strategies for rank pursuit [49] generally finds very high inter-rater correlations of subject's dominance (approx. 78–0.88 in [49]; greater than 0.8 in [51]), and Cronbach's alpha (0.83 in [56]; 0.83–0.93 in [51]; 0.86 in [115]), indicating that naturalistic groups reach near-consensus on a dominance construct that demonstrates excellent validity according to standard psychological criteria. Empirically, measured dominance and prestige tend to be uncorrelated (r = 0.03–0.12 in [49]; r = 0.01 in [51r = −0.12–0.17 in [117]) or negatively correlated (e.g. [129]), which means that the high level of collinearity that people believe exists between prestige and dominance in [3] may not be empirically reflected in naturalistic groups in the laboratory or the field. An older tradition in the measurement of dominance inspired by primate ethology uses purely relational measures (such as the direction of unreciprocated agonistic behaviours) to measure dominance as an emergent phenomenon specific to a group, which is closer to the theoretical foundations of dominance as a concept. When used together with survey-assessed trait dominance, relational and trait dominance strongly correlate, regardless of whether the survey is filled by observers or by group participants [12]. Overall, the evidence points to the importance of avoiding self-report measures in favour of integrating both other-report measures and ethological observations to produce secure measurements of the dominance construct.

(b) Gender-specific effects

Current research supports the view that dominance plays a role in status attainment for both men and women in same and mixed-gender contexts [51,64,115,117,118]. However, evidence exists for gender-specificity in the way dominance impacts social status. For example, in a study of status among same-sex face-to-face groups in Canada [51], women perceived as dominant were deemed less likeable by other women (r = −0.24, p = 0.025), whereas dominant men incurred little to no social penalty (r = 0.08, p = 0.43). Among the egalitarian Chabu in Ethiopia, dominance contributed less to leadership attainment among women than among men [55].

One potential explanation for this comes from social role theory [149]: women's lower status across societies results from social norms emphasizing that women ought to be communal—warm, nurturing, kind—while men should strive to be agentic—assertive, authoritative and independent [150152]. A proclivity to sanction gender norm violations [153,154] may result in backlash against women who exercise dominance, who are often described by scholars as overly agentic relative to norm expectations [155158]. Backlash occurs even when dominant women seek to lead groups with communal and other-serving (stereotypically feminine) goals [159], and among same-sex sanctioners [160]. Alternatively, because men and women may have tended to solve problems in different social domains over evolutionary history, dominance may be a more socially valued trait in men than in women for both cultural and biological reasons [161]—a hypothesis that may be tested with further cross-cultural research.

(c) The social dynamics of prestige and dominance

While prestige and dominance coexist as pathways to status in humans, they need not operate independently. Many high-status individuals may derive influence from both prestige and dominance processes. This is especially important given the factors reviewed that limit the effectiveness of coercive tactics alone. Alongside the more straightforward process where subordinates are compelled into compliance exclusively via coercive threats, three mechanisms may produce an overlap between dominance and prestige status components.

First, culturally evolved institutional hierarchies may grant formal leaders, managers and other authorities power through control over rewards and punishments, which creates the conditions for dominance via coercive threats; institutionally powerful individuals tend to resort to dominant social tactics especially when prestige is lost [162]. Because such positions may in some societies be attained (or be assumed to be attained) through skill, competence or knowledge, high-status authorities may demonstrate prestige ethology even as they keep aggressive or coercive tactics in their toolboxes for use in limited occasions. Such roles may exist even in egalitarian societies, for example among shamans, who tend to be simultaneously respected and feared [56,163].

Second, traits, attributes and motivations that generate coercive threat may themselves constitute valued abilities worthy of emulation or deference in some situations. Physically formidable men may be seen as more capable of generating benefits for in-group members through their perceived capacity to punish free-riders, to facilitate inter-group competition [134,164,165] or to compel broader coalitional support from others [1,52].

Third, displays of confidence, which are frequent among dominant individuals [166] can lead to an undeserved prestigious reputation relative to their true skill. This will depend on the quality of information on other's skill levels, meaning that this mechanism is more likely to operate in complex large-scale societies with high levels of specialization and where ephemeral interactions with strangers are important.