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Meacham AM, Sosnowski MJ, Kleider-Offutt HM, Brosnan SF. Capuchin monkeys' (Sapajus [Cebus] apella) categorization of photos of unknown male conspecifics suggests attention to fWHR and a dominance bias. Am J Primatol 2024; 86:e23623. [PMID: 38528366 DOI: 10.1002/ajp.23623] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2023] [Revised: 02/07/2024] [Accepted: 03/10/2024] [Indexed: 03/27/2024]
Abstract
The ability to quickly perceive others' rank minimizes costs by helping individuals behave appropriately when interacting with strangers. Indeed, humans and at least some other species can quickly determine strangers' rank or dominance based only on physical features without observing others' interactions or behavior. Nonhuman primates can determine strangers' ranks by observing their interactions, and some evidence suggests that at least some cues to dominance, such as facial width-to-height ratio (fWHR), are also present in other primates. However, it is unknown whether they can determine strangers' rank simply by looking at their faces, rather than observing their interactions. If so, this would suggest selective pressure across the primates on both cues to dominance and the ability to detect those cues accurately. To address this, we examined the ability of male and female tufted capuchin monkeys (Sapajus [Cebus] apella) to categorize images of the faces of unknown conspecifics (Sapajus from different colonies) and humans (computer-generated and real) as dominant or nondominant based only on still images. Capuchins' categorization of unknown conspecific faces was consistent with fWHR, a cue to dominance, although there was a strong tendency to categorize strangers as dominant, particularly for males. This was true despite the continued correct categorization of known individuals. In addition, capuchins did not categorize human strangers in accordance with external pre-ratings of dominance by independent human raters, despite the availability of the same cue, fWHR. We consider these results in the context of capuchin socio-ecology and what they mean for the evolution of rapid decision-making in social contexts.
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Affiliation(s)
- Ashley M Meacham
- Department of Psychology, Georgia State University, Atlanta, Georgia, USA
| | - Meghan J Sosnowski
- Department of Psychology, Georgia State University, Atlanta, Georgia, USA
- Language Research Center, Georgia State University, Decatur, Georgia, USA
| | - Heather M Kleider-Offutt
- Department of Psychology, Georgia State University, Atlanta, Georgia, USA
- Neuroscience Institute, Georgia State University, Atlanta, Georgia, USA
| | - Sarah F Brosnan
- Department of Psychology, Georgia State University, Atlanta, Georgia, USA
- Language Research Center, Georgia State University, Decatur, Georgia, USA
- Neuroscience Institute, Georgia State University, Atlanta, Georgia, USA
- Center for Behavioral Neuroscience, Georgia State University, Atlanta, Georgia, USA
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Brown M, Tracy RE. Preliminary evidence for neck musculature in shaping functional stereotypes of men's relationship motives. Scand J Psychol 2024; 65:136-143. [PMID: 37641888 DOI: 10.1111/sjop.12963] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2022] [Revised: 07/12/2023] [Accepted: 08/10/2023] [Indexed: 08/31/2023]
Abstract
Neck musculature is reliably diagnostic of men's formidability and central to several inferences of their physical prowess. These inferences facilitate stereotypes of men's social value from which perceivers estimate their abilities to satisfy reproductive goals related to mate acquisition and parental care. Participants evaluated men's interest in various mating and parenting strategies, wherein men varied in the size of visible neck musculature through trapezii and sternocleidomastoids for perceivers to identify potential reproductive interests and goals. Large trapezii elicited perceptions of men as more effective at protecting offspring, albeit at the expense of nurturance and interest in long-term pair bonds. Results extend previous findings implicating formidability as central to relationship decisions by considering a novel modality.
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Affiliation(s)
- Mitch Brown
- University of Arkansas, Fayetteville, AR, USA
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Murray L, Goddard J, Gordon D. Facial Expression of TIPI Personality and CHMP-Tri Psychopathy Traits in Chimpanzees (Pan troglodytes) : Evidence for Honest Signalling? HUMAN NATURE (HAWTHORNE, N.Y.) 2023; 34:513-538. [PMID: 37934332 PMCID: PMC10739467 DOI: 10.1007/s12110-023-09462-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 09/24/2023] [Indexed: 11/08/2023]
Abstract
Honest signalling theory suggests that humans and chimpanzees can extract socially relevant information relating to personality from the faces of their conspecifics. Humans are also able to extract information from chimpanzees' faces. Here, we examine whether personality characteristics of chimpanzees, including measures of psychopathy, can be discerned based purely on facial morphology in photographs. Twenty-one chimpanzees were given naïve and expert personality ratings on the Ten Item Personality Inventory (TIPI) and the Chimpanzee Triarchic Model of Psychopathy (CHMP-Tri) before and following behavioural observations. Characteristics relating to openness, conscientiousness, extraversion, and disinhibition could be distinguished from the faces of chimpanzees. Individuals higher on disinhibition have lower scores on conscientiousness and emotional stability and higher scores on extraversion, while those higher on meanness have lower conscientiousness and agreeableness. Facial expressions are linked to personality traits present in the TIPI and CHMP-Tri models: the Relaxed Face and the Grooming Face were displayed more by chimpanzees higher on agreeableness, whereas the Compressed Lips Face was observed more in those individuals higher on boldness, and the Full Open Grin was displayed more by chimpanzees higher on extraversion but lower on emotional stability and conscientiousness. Facial expressions were also found to be associated with particular behavioural contexts, namely the Grooming Face in affiliative contexts and the Relaxed and Relaxed Open Mouth Faces in neutral contexts. Dominant chimpanzees display higher levels of boldness and more Compressed Lips Faces, Relaxed Open Mouth Faces, and Grooming Faces than subordinate individuals. These findings support and extend evidence for an honest signalling system and a personality structure shared between humans and chimpanzees. Future research could further explore how personality is conveyed through the face, perhaps through more than just singular aspects of character, and maybe reflecting what chimpanzees themselves are able to do.
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Affiliation(s)
- Lindsay Murray
- School of Psychology, University of Chester, Chester, UK.
| | - Jade Goddard
- School of Psychology, University of Chester, Chester, UK
| | - David Gordon
- School of Psychology, University of Chester, Chester, UK
- School of Health, Science and Wellbeing, Staffordshire University, Stoke-On-Trent, UK
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Wilson VAD, Masilkova M. Does the primate face cue personality? PERSONALITY NEUROSCIENCE 2023; 6:e7. [PMID: 38107779 PMCID: PMC10725780 DOI: 10.1017/pen.2023.5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Revised: 05/24/2023] [Accepted: 05/31/2023] [Indexed: 12/19/2023]
Abstract
When looking at others, primates primarily focus on the face - detecting the face first and looking at it longer than other parts of the body. This is because primate faces, even without expression, convey trait information crucial for navigating social relationships. Recent studies on primates, including humans, have linked facial features, specifically facial width-to-height ratio (fWHR), to rank and Dominance-related personality traits, suggesting these links' potential role in social decisions. However, studies on the association between dominance and fWHR report contradictory results in humans and variable patterns in nonhuman primates. It is also not clear whether and how nonhuman primates perceive different facial cues to personality traits and whether these may have evolved as social signals. This review summarises the variable facial-personality links, their underlying proximate and evolutionary mechanisms and their perception across primates. We emphasise the importance of employing comparative research, including various primate species and human populations, to disentangle phylogeny from socio-ecological drivers and to understand the selection pressures driving the facial-personality links in humans. Finally, we encourage researchers to move away from single facial measures and towards holistic measures and to complement perception studies using neuroscientific methods.
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Affiliation(s)
- Vanessa A D Wilson
- Department of Comparative Cognition, Institute of Biology, University of Neuchâtel, Neuchâtel, Switzerland
- Department of Comparative Language Science, University of Zurich, Zurich, Switzerland
- Center for the Interdisciplinary Study of Language Evolution (ISLE), University of Zurich, Zurich, Switzerland
| | - Michaela Masilkova
- Department of Game Management and Wildlife Biology, Faculty of Forestry and Wood Sciences, Czech University of Life Sciences, Prague, Czech Republic
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Men’s Expectations for Postconflict Reconciliation with Physically Strong Opponents. EVOLUTIONARY PSYCHOLOGICAL SCIENCE 2022. [DOI: 10.1007/s40806-022-00350-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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Masi M, Mattavelli S, Fasoli F, Brambilla M. When faces and voices come together: Face width‐to‐height ratio and voice pitch contribute independently to social perception. EUROPEAN JOURNAL OF SOCIAL PSYCHOLOGY 2022. [DOI: 10.1002/ejsp.2905] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- Matteo Masi
- University of Milano‐Bicocca MilanoItaly
- University of SurreyGuildfordUK
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Banai B, Bačić M, Banai IP. Preference for leaders with high and low facial width-to-height ratios: moderating roles of political ideology and voting context. CURRENT ISSUES IN PERSONALITY PSYCHOLOGY 2022; 11:29-38. [PMID: 38013826 PMCID: PMC10654341 DOI: 10.5114/cipp/151672] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2021] [Revised: 01/04/2022] [Accepted: 06/28/2022] [Indexed: 11/29/2023] Open
Abstract
BACKGROUND It has been argued that human ancestors evolved greater sensitivity to certain traits that signal dominance in potential leaders. From this perspective, modern voters still favor certain physical characteristics during political elections. Indeed, previous studies have shown that voters prefer dominant candidates, especially when primed with wartime scenarios, and with conservative voters being more likely to choose a dominant leader. Because facial width-to-height ratio (fWHR) was found to be positively associated with perceived dominance, we sought to investigate the effect of fWHR on leader preference by taking into an account voting context and voters' political ideology. PARTICIPANTS AND PROCEDURE A total of 148 participants took part in two online experiments in which we manipulated standardized facial images to represent faces with low and high fWHR. Furthermore, we assessed participants' political ideology and asked them to rate the extent to which faces with low and high fWHR looked like leaders during wartime and peacetime scenarios. RESULTS Preference for leaders with high fWHR was positively related to participants' political ideology, but only in a wartime scenario, suggesting that the more conservative participants were, the higher was their preference for leaders with high fWHR. This is consistent with the notion that preferences for dominant-looking leaders vary as a function of the contextual (voting context) and individual differences (political ideology). CONCLUSIONS The present findings provide new evidence for the contribution of fWHR in leader preference and significantly adds to the results of previous research demonstrating the roles of voters' political ideology and politicians' physical characteristics in perceiving leadership abilities.
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Affiliation(s)
| | - Marinela Bačić
- Department of Psychology, University of Zadar, Zadar, Croatia
| | - Irena Pavela Banai
- Faculty of Humanities and Social Sciences, J. J. Strossmayer University of Osijek, Osijek, Croatia
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Covariation between formidability inferences and perceptions of men's preferred humor styles. PERSONALITY AND INDIVIDUAL DIFFERENCES 2022. [DOI: 10.1016/j.paid.2022.111792] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Facial width to height ratio and perceived aggression: The disjunction effect of horizontal and vertical components. PERSONALITY AND INDIVIDUAL DIFFERENCES 2022. [DOI: 10.1016/j.paid.2022.111578] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Summersby S, Harris B, Denson TF, White D. Tracking sexual dimorphism of facial width-to-height ratio across the lifespan: implications for perceived aggressiveness. ROYAL SOCIETY OPEN SCIENCE 2022. [PMID: 35592758 DOI: 10.6084/m9.figshare.c.5953414] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
The facial width-to-height ratio (FWHR) influences social judgements like perceived aggression. This may be because FWHR is a sexually dimorphic feature, with males having higher FWHR than females. However, evidence for sexual dimorphism is mixed, little is known about how it varies with age, and the relationship between sexual dimorphism and perceived aggressiveness is unclear. We addressed these gaps by measuring FWHR of 17 607 passport images of male and female faces across the lifespan. We found larger FWHR in males only in young adulthood, aligning with the stage most commonly associated with mate selection and intrasexual competition. However, the direction of dimorphism was reversed after 48 years of age, with females recording larger FWHRs than males. We then examined how natural variation in FWHR affected perceived aggressiveness. The relationship between FWHR and perceived aggressiveness was strongest for males at 27-33 and females at 34-61. Raters were most sensitive to differences in FWHR for young adult male faces, pointing to enhanced sensitivity to FWHR as a cue to aggressiveness. This may reflect a common mechanism for evaluating male aggressiveness from variability in structural (FWHR) and malleable (emotional expression) aspects of the face.
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Affiliation(s)
- Stephanie Summersby
- School of Psychology, University of New South Wales, Sydney, New South Wales 2052, Australia
| | - Bonnie Harris
- School of Psychology, University of New South Wales, Sydney, New South Wales 2052, Australia
| | - Thomas F Denson
- School of Psychology, University of New South Wales, Sydney, New South Wales 2052, Australia
| | - David White
- School of Psychology, University of New South Wales, Sydney, New South Wales 2052, Australia
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Brown M, Sacco DF, Barbaro N, Drea KM. Contextual factors that heighten interest in coalitional alliances with men possessing formidable facial structures. EVOL HUM BEHAV 2022. [DOI: 10.1016/j.evolhumbehav.2022.05.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
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12
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Summersby S, Harris B, Denson TF, White D. Tracking sexual dimorphism of facial width-to-height ratio across the lifespan: implications for perceived aggressiveness. ROYAL SOCIETY OPEN SCIENCE 2022; 9:211500. [PMID: 35592758 PMCID: PMC9066300 DOI: 10.1098/rsos.211500] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/16/2021] [Accepted: 04/01/2022] [Indexed: 05/03/2023]
Abstract
The facial width-to-height ratio (FWHR) influences social judgements like perceived aggression. This may be because FWHR is a sexually dimorphic feature, with males having higher FWHR than females. However, evidence for sexual dimorphism is mixed, little is known about how it varies with age, and the relationship between sexual dimorphism and perceived aggressiveness is unclear. We addressed these gaps by measuring FWHR of 17 607 passport images of male and female faces across the lifespan. We found larger FWHR in males only in young adulthood, aligning with the stage most commonly associated with mate selection and intrasexual competition. However, the direction of dimorphism was reversed after 48 years of age, with females recording larger FWHRs than males. We then examined how natural variation in FWHR affected perceived aggressiveness. The relationship between FWHR and perceived aggressiveness was strongest for males at 27-33 and females at 34-61. Raters were most sensitive to differences in FWHR for young adult male faces, pointing to enhanced sensitivity to FWHR as a cue to aggressiveness. This may reflect a common mechanism for evaluating male aggressiveness from variability in structural (FWHR) and malleable (emotional expression) aspects of the face.
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Affiliation(s)
- Stephanie Summersby
- School of Psychology, University of New South Wales, Sydney, New South Wales 2052, Australia
| | - Bonnie Harris
- School of Psychology, University of New South Wales, Sydney, New South Wales 2052, Australia
| | - Thomas F. Denson
- School of Psychology, University of New South Wales, Sydney, New South Wales 2052, Australia
| | - David White
- School of Psychology, University of New South Wales, Sydney, New South Wales 2052, Australia
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Butovskaya ML, Rostovtseva VV, Mezentseva AA. Facial and body sexual dimorphism are not interconnected in the Maasai. J Physiol Anthropol 2022; 41:3. [PMID: 34996526 PMCID: PMC8740871 DOI: 10.1186/s40101-021-00276-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2021] [Accepted: 12/10/2021] [Indexed: 11/22/2022] Open
Abstract
BACKGROUND In this paper, we investigate facial sexual dimorphism and its' association with body dimorphism in Maasai, the traditional seminomadic population of Tanzania. We discuss findings on other human populations and possible factors affecting the developmental processes in Maasai. METHODS Full-face anthropological photographs were obtained from 305 Maasai (185 men, 120 women) aged 17-90 years. Facial shape was assessed combining geometric morphometrics and classical facial indices. Body parameters were measured directly using precise anthropological instruments. RESULTS Sexual dimorphism in Maasai faces was low, sex explained 1.8% of the total shape variance. However, male faces were relatively narrower and vertically prolonged, with slightly wider noses, narrower-set and lower eyebrows, wider mouths, and higher forehead hairline. The most sexually dimorphic regions of the face were the lower jaw and the nose. Facial width-to-height ratio (fWHR), measured in six known variants, revealed no significant sexual dimorphism. The allometric effects on facial traits were mostly related to the face growth, rather than the growth of the whole body (body height). Significant body dimorphism was demonstrated, men being significantly higher, with larger wrist diameter and hand grip strength, and women having higher BMI, hips circumferences, upper arm circumferences, triceps skinfolds. Facial and body sexual dimorphisms were not associated. CONCLUSIONS Facial sex differences in Maasai are very low, while on the contrary, the body sexual dimorphism is high. There were practically no associations between facial and body measures. These findings are interpreted in the light of trade-offs between environmental, cultural, and sexual selection pressures.
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Affiliation(s)
- Marina L Butovskaya
- Institute of Ethnology and Anthropology, Russian Academy of Sciences, Moscow, 119334, Russia.
- The National Research University Higher School of Economics, Moscow, 101000, Russia.
- Russian State University for the Humanities, Moscow, 125047, Russia.
| | - Victoria V Rostovtseva
- Institute of Ethnology and Anthropology, Russian Academy of Sciences, Moscow, 119334, Russia
| | - Anna A Mezentseva
- Institute of Ethnology and Anthropology, Russian Academy of Sciences, Moscow, 119334, Russia
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