Battle of the Sexes
Can an 'Extreme Female Brain' be characterised in terms of psychosis?
Mark Brosnan, Chris Ashwin, Ian Walker & Joseph Donaghue
Personality and Individual Differences, forthcoming
Abstract:
The empathising-systemising (E-S) theory proposes that many sex differences can be explained by females typically demonstrating greater empathising abilities (understanding of the social world) and males typically demonstrating greater systemising abilities (understanding of the non-social world). Autism is argued to represent an 'Extreme Male Brain', with impaired empathising alongside preserved or enhanced systemising producing a hypo-empathising profile. A recent account hypothesised that a hyper-empathising 'Extreme Female Brain' would be characterised in terms of psychosis. The present study tests this hypothesis by investigating the relationship between levels of empathising and systemising, as well as self-report measures of psychosis, depression and anxiety, in 70 healthy female undergraduates. Results showed a hyper-empathising profile was related to psychosis, and specifically paranoia and mania (positive symptoms). No relationship was found between hyper-empathising and either depression or anxiety, consistent with the idea that an 'Extreme Female Brain' is specifically associated with psychosis. In addition, empathising and systemising were found to negatively correlate with each other, suggesting they are separate but related components.
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Ilanit Gordon, Orna Zagoory-Sharon, James Leckman & Ruth Feldman
Hormones and Behavior, August 2010, Pages 513-518
Abstract:
Animal studies have implicated the neuropeptides Prolactin (PRL) and Oxytocin (OT) in processes of maternal bonding and PRL has similarly been shown to play a role in the neurophysiology of fatherhood. Yet, very little is known on the involvement of PRL and OT in human fathering. Forty-three fathers and their firstborn infant were seen twice: in the second and sixth postpartum months. Paternal plasma PRL and OT were sampled at both time-points and analyzed with ELISA methods. At six months fathers were videotaped interacting with their child in social and exploratory play contexts and interactions were micro-analyzed for father-infant Affect Synchrony and father facilitation of child toy exploration. PRL and OT showed high individual stability across time and were correlated at the second observation. PRL was related to father-infant Coordinated Exploratory Play in the toy context whereas OT was associated with father-infant Affect Synchrony in the social context. Results point to the role of PRL and OT in the development of human fathering and underscore their differential relations with patterns of paternal care.
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Social, Behavioral, and Biological Factors, and Sex Differences in Mortality
Richard Rogers, Bethany Everett, Jarron Saint Onge & Patrick Krueger
Demography, August 2010, Pages 555-578
Abstract:
Few studies have examined whether sex differences in mortality are associated with different distributions of risk factors or result from the unique relationships between risk factors and mortality for men and women. We extend previous research by systematically testing a variety of factors, including health behaviors, social ties, socioeconomic status, and biological indicators of health. We employ the National Health and Nutritional Examination Survey III Linked Mortality File and use Cox proportional hazards models to examine sex differences in adult mortality in the United States. Our findings document that social and behavioral characteristics are key factors related to the sex gap in mortality. Once we control for women's lower levels of marriage, poverty, and exercise, the sex gap in mortality widens; and once we control for women's greater propensity to visit with friends and relatives, attend religious services, and abstain from smoking, the sex gap in mortality narrows. Biological factors - including indicators of inflammation and cardiovascular risk - also inform sex differences in mortality. Nevertheless, persistent sex differences in mortality remain: compared with women, men have 30% to 83% higher risks of death over the follow-up period, depending on the covariates included in the model. Although the prevalence of risk factors differs by sex, the impact of those risk factors on mortality is similar for men and women.
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Gender differences in cooperation with group membership
Gary Charness & Aldo Rustichini
Games and Economic Behavior, forthcoming
Abstract:
We study experimentally how males and females differ in the way same-gender peers observing their action affects their social behavior. In our experiment, people play a Prisoner's Dilemma Game with a partisan audience watching the choice. Two groups participated in each session; these groups could be both all-male, both all-female, or one all-male and one all-female. Groups were separated into two rooms. Each person in the group played the game once with an audience of the same group and once with audience of the other group. Behavior is significantly affected by the interaction of gender and place: males cooperate substantially less often when observed by their peer group, while females cooperate substantially more often. We discuss a possible explanation for this pattern: Males and females wish to signal their in-group peers, but males wish to signal their formidability and females wish to signal their cooperativeness.
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Charles Cook & Deborah Saucier
Personality and Individual Differences, forthcoming
Abstract:
Sex differences on such tasks as Vandenberg's mental rotation and skilled targeting are well established with men showing performance advantages compared to women. Baron-Cohen's Empathizing-Systemizing Theory of Sex Differences (E/S theory) suggests that male and female brains adopt different cognitive biases with male brains 'systemizing' and female brains 'empathizing'. We explored the relation between abilities that typically demonstrate male advantages and performance on Systemizing Quotient (SQ), Empathizing Quotient (EQ) and 'Reading the Mind in the Eyes' (RMET). We hypothesized men should demonstrate superior performance on targeting, MROT and SQ task/questionnaire and that women should demonstrate superior performance on EQ and RMET. Significant sex differences were found for SQ, EQ, targeting and MROT, but not for RMET. Regression indicated that MROT was significantly predicted by higher SQ, lower EQ and unexpectedly, higher RMET scores. Regression indicated that individuals high in EQ and low in SQ were less accurate on the targeting task with their dominant hand, although high SQ individuals tended to be more accurate on targeting with their non-dominant hand. No relation between targeting and RMET scores was found. Thus, the E/S theory provides predictive power for spatial tasks that typically show male advantages.
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Sexual Orientation Perception Involves Gendered Facial Cues
Jonathan Freeman, Kerri Johnson, Nalini Ambady & Nicholas Rule
Personality and Social Psychology Bulletin, forthcoming
Abstract:
Perceivers can accurately judge a face's sexual orientation, but the perceptual mechanisms mediating this remain obscure. The authors hypothesized that stereotypes casting gays and lesbians as gender "inverts," in cultural circulation for a century and a half, lead perceivers to use gendered facial cues to infer sexual orientation. Using computer-generated faces, Study 1 showed that as two facial dimensions (shape and texture) became more gender inverted, targets were more likely to be judged as gay or lesbian. Study 2 showed that real faces appearing more gender inverted were more likely to be judged as gay or lesbian. Furthermore, the stereotypic use of gendered cues influenced the accurate judgment of sexual orientation. Although using gendered cues increased the accuracy of sexual orientation judgments overall, Study 3 showed that judgments were reliably mistaken for targets that countered stereotypes. Together, the findings demonstrate that perceivers utilize gendered facial cues to glean another's sexual orientation, and this influences the accuracy or error of judgments.
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Hand-grip strength and sensation seeking
Bernhard Fink, Aicha Hamdaoui, Frederike Wenig & Nick Neave
Personality and Individual Differences, forthcoming
Abstract:
Sensation seeking denotes the tendency to seek novel, varied, complex, and intense sensations and experiences, and describes the willingness to take risks for the sake of such experiences. Some studies have demonstrated correlates of both circulating and prenatal testosterone with sensation seeking. Hand-grip strength (as a measure of overall muscular strength) is also known to show associations with measures of circulating testosterone, and certain physical and behavioural characteristics, particularly in men. This study examines the possible relationship between hand-grip strength and sensation seeking, assessed via the Sensation Seeking Scale Form V (SSS-V) in 117 males aged 18-30 years. A positive and significant correlation was found between hand-grip strength and SSS-V total score and thrill and adventure seeking (TAS) after controlling for weight, height, and engagement with sporting activities. We discuss our findings with reference to other studies reporting associations between biological and personality characteristics.
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Jessica Hall, Sam Hutton & Michael Morgan
Cognition & Emotion, June 2010, Pages 629-637
Abstract:
Previous meta-analyses support a female advantage in decoding non-verbal emotion (Hall, 1978, 1984), yet the mechanisms underlying this advantage are not understood. The present study examined whether the female advantage is related to greater female attention to the eyes. Eye-tracking techniques were used to measure attention to the eyes in 19 males and 20 females during a facial expression recognition task. Women were faster and more accurate in their expression recognition compared with men, and women looked more at the eyes than men. Positive relationships were observed between dwell time and number of fixations to the eyes and both accuracy of facial expression recognition and speed of facial expression recognition. These results support the hypothesis that the female advantage in facial expression recognition is related to greater female attention to the eyes.
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Preschoolers' Mental Rotation: Sex Differences in Hemispheric Asymmetry
Nicola Hahn, Petra Jansen & Martin Heil
Journal of Cognitive Neuroscience, June 2010, Pages 1244-1250
Abstract:
Mental rotation performance has been found to produce one of the largest sex differences in cognition accompanied by sex differences in functional cerebral asymmetry. Although sex differences in mental rotation performance can be reliably demonstrated as early as age 5 years old, that is, long before puberty, no data exist as to whether preschooler's mental rotation performance is accompanied by sex differences in functional cerebral asymmetry. Based on the electrophysiological brain correlates of mental rotation, we observed a bilateral parietal brain activity for preschool boys whereas the preschool girls' brain activity was clearly lateralized toward the left hemisphere if and only if mental rotation was needed to solve the task. Thus, sex differences in functional cerebral asymmetry during mental rotation do not require hormonal changes that occur during puberty.
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Behavioural and Biological Determinants of Human Sex Ratio at Birth
William James
Journal of Biosocial Science, September 2010, Pages 587-599
Abstract:
The human sex ratio SR (proportion male) at birth has been reported to vary with many variables. The explanation of this variation is not established, but I have hypothesized that it is partially caused by the hormonal concentrations of both parents around the time of conception. The present note suggests how this hypothesis might accommodate recent sex ratio findings relating to 'psychosexual restriction', female genital cutting, sexes of prior sibs, finger length ratios, the autism spectrum disorder, parental occupation and maternal eating disorders. Tests of such suggestions are offered, and it is hypothesized that: (a) in women, Manning's R (the ratio of the lengths of the 2nd and 4th digits) is positively correlated with offspring sex ratio (proportion male); (b) women who have undergone female genital cutting (FGC) have high androgen levels; (c) offspring sex ratio correlates positively with 'masculinity' of parental occupation, the correlation being mediated by testosterone levels. It is noted that the lines of evidence for three hypotheses (James', Manning's and Baron-Cohen's) are mutually supportive.
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The second to fourth digit ratio: A measure of two hormonally-based temperament dimensions
Helen Fisher, Jonathan Rich, Heide Island & Daniel Marchalik
Personality and Individual Differences, forthcoming
Abstract:
Constellations of biobehavioral traits are associated with activity in the testosterone and estrogen systems, due to fetal priming or hormonal alterations during the life course. Using these data, we developed two 14-item measures to investigate the traits associated with these hormone systems. To reach adequate internal consistency, we used participants of an Internet dating site; the final sample was 39,913 individuals. Factorial structure and correlations with several validating criteria were consistent with the hypothesis that these scales measured these neurochemical systems ([Fisher, 2009] and [Fisher et al., in preparation]). Two of these validity measures are discussed: gender loading of each scale; and degree to which members of each scale pursued particular occupations. Then we investigated the hypothesis that individuals scoring high on either of these scales also expressed a specific second to fourth digit ratio of the right hand. Individuals who reported a longer 4th finger relative to 2nd expressed high scores on the proposed testosterone scale; individuals who reported a longer 2nd finger relative to 4th or 2nd and 4th digits of equal length expressed high scores on the proposed estrogen/oxytocin scale. These data are consistent with the hypothesis that these 2D:4D ratios are artifacts of hormonal priming in utero.
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Sex differences in face processing: Are women less lateralized and faster than men?
Ornella Godard & Nicole Fiori
Brain and Cognition, August 2010, Pages 167-175
Abstract:
The aim of this study was to determine the influence of sex on hemispheric asymmetry and cooperation in a face recognition task. We used a masked priming paradigm in which the prime stimulus was centrally presented; it could be a bisymmetric face or a hemi-face in which facial information was presented in the left or the right visual field and projected to the right or the left hemisphere. The target stimulus was always a bisymmetric face presented centrally. Faces were selected from Minear and Park's (2004) database. Fifty-two right-handed students (26 men, 26 women) participated in this experiment, in which accuracy (percentage of correct responses) and reaction times (RTs in ms) were measured. Although accuracy data showed that the percentage of correct recognition - when prime and target matched - was equivalent in men and women, men's RTs were longer than women's in all conditions. Accuracy and RTs showed that men are more strongly lateralized than women, with right hemispheric dominance. These results suggest that men are as good at face recognition as women, but there are functional differences in the two sexes. The findings are discussed in terms of functional cerebral networks distributed over both hemispheres and of interhemispheric transmission.
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Multi-method personality assessment of butchers and hunters: Beliefs and reality
Martin Voracek, Daniela Gabler, Carmen Kreutzer, Stefan Stieger, Viren Swami & Anton Formann
Personality and Individual Differences, forthcoming
Abstract:
Two studies examined beliefs about the personality of male butchers and hunters and the factuality of such beliefs. These professions' daily routines involve killing animals and handling their carcasses, acts that could be facilitated by specific personality constellations. Study 1 (102 raters) evidenced perceptions of higher aggressiveness and masculinity of butchers/hunters and higher self-esteem (hunters only), as compared with average men. In contrast, Study 2 found little evidence for the factuality of such beliefs, based on multi-method personality assessments in a case-control design of 96 men (23 and 25 dyads including one butcher or hunter, matched with same-generation, other-occupation friends or relatives). Only implicit, but not explicit, aggressiveness (measured with an Implicit Association Test) was higher in butchers/hunters than in controls. Both masculinity (whether measured unobtrusively [digit ratio, 2D:4D] or explicitly) and self-esteem (whether measured implicitly [name-letter effect] or explicitly) were comparable for butchers/hunters and controls. Lower self-reported conscientiousness, extraversion, and openness in butchers/hunters than controls were not generalizable to informant reports of these Big Five dimensions. Discussion focuses on the merits of utilizing belief-factuality contrasts, controlled designs, and multi-method assessments in personality research.