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Mast Cells in the Developing Brain Determine Adult Sexual Behavior
Kathryn Lenz et al.
Journal of Neuroscience, 12 September 2018, Pages 8044-8059
Abstract:
Many sex differences in brain and behavior are programmed during development by gonadal hormones, but the cellular mechanisms are incompletely understood. We found that immune-system-derived mast cells are a primary target for the masculinizing hormone estradiol and that mast cells are in turn primary mediators of brain sexual differentiation. Newborn male rats had greater numbers and more activated mast cells in the preoptic area (POA), a brain region essential for male copulatory behavior, than female littermates during the critical period for sexual differentiation. Inhibiting mast cells with a stabilizing agent blunted the masculinization of both POA neuronal and microglial morphology and adult sex behavior, whereas activating mast cells in females, even though fewer in number, induced masculinization. Treatment of newborn females with a masculinizing dose of estradiol increased mast cell number and induced mast cells to release histamine, which then stimulated microglia to release prostaglandins and thereby induced male-typical synaptic patterning. These findings identify a novel non-neuronal origin of brain sex differences and resulting motivated behaviors.
Women's fertility cues affect cooperative behavior: Evidence for the role of the human putative chemosignal estratetraenol
Chen Oren & Simone Shamay-Tsoory
Psychoneuroendocrinology, March 2019, Pages 50-59
Abstract:
Previous studies demonstrating that women’s body odor during ovulation is perceived as more attractive suggest that exposure to women’s chemosignals of high fertility increases mating motivation. Building on previous evidence showing that cooperative behaviors are perceived as attractive, in the current study we investigated whether chemosignals of women's fertility affect men's tendency to behave cooperatively. In the first experiment we found that in the presence of women's body odor during ovulation, men increase their tendency to apply a cooperative strategy, while their tendency to apply an individualistic strategy decreases. To examine the mechanism underlying this effect, we tested a different sample of men exposed to the putative human pheromone estratetraenol (estra-1,3,5(10),16-tetraen-3-ol) or to a control solution. Exposure to estratetraenol compared with control yielded strikingly similar effects of increased cooperation. The results indicate that women's chemosignals of high fertility increase mating motivation among man, encouraging them to act in a cooperative manner toward others, a response that may highlight their attractive qualities and thus attract mates. We further conclude that estratetraenol may serve as one of the biological agents that mediate the behavioral effects of women's chemosignals of fertility on social behavior.
Human chemosignals modulate emotional perception of biological motion in a sex-specific manner
Yuting Ye et al.
Psychoneuroendocrinology, February 2019, Pages 246-253
Abstract:
Androsta-4,16,-dien-3-one and estra-1,3,5(10),16-tetraen-3-ol have previously been shown to communicate opposite sex information that is differently effective to the two sex groups. The current study critically examines if the two human steroids could facilitate interactions with potential mates rather than competitors by acting on the recipients’ emotional perception in a sex-appropriate manner. Using dynamic point-light displays that portray the gaits of walkers whose emotional states are digitally morphed along the valence and the arousal axes, we show that smelling androstadienone subconsciously biases heterosexual women, but not men, towards perceiving the male, but not female, walkers as happier and more relaxed. By contrast, smelling estratetraenol subconsciously biases heterosexual men, but not women, towards perceiving the female, but not male, walkers as happier and more relaxed. These findings indicate that androstadienone and estratetraenol prime the identification of emotionally receptive states for the potential mates with whom they are associated, in manners contingent upon not only the recipients’ own sex but also their sex perception of other individuals that ensure sex-appropriate behavior.
No evidence that facial attractiveness, femininity, averageness, or coloration are cues to susceptibility to infectious illnesses in a university sample of young adult women
Ziyi Cai et al.
Evolution and Human Behavior, forthcoming
Abstract:
Previous reports that women with attractive faces are healthier have been widely cited as evidence that sexual selection has shaped human mate preferences. However, evidence for correlations between women's physical health and facial attractiveness is equivocal. Moreover, positive results on this issue have generally come from studies of self-reported health in small samples. The current study took standardized face photographs of women who completed three different health questionnaires assessing susceptibility to infectious illnesses (N = 590). Of these women, 221 also provided a saliva sample that was assayed for immunoglobulin A (a marker of immune function). Analyses showed no significant correlations between rated facial attractiveness and either scores on any of the health questionnaires or salivary immunoglobulin A. Furthermore there was no compelling evidence that objective measures of sexual dimorphism of face shape, averageness of face shape, or facial coloration were correlated with any of our health measures. While other measures of health may yet reveal robust associations with facial appearance, these null results do not support the prominent and influential assumption that women's facial attractiveness is a cue of young adult women's susceptibility to infectious illnesses, at least in our study population.
A Rosier Reality: Incongruency in Stated and Revealed Ingroup Preferences among Young Asian American Speed Daters
Karen Wu, Chuansheng Chen & Ellen Greenberger
Social Psychology Quarterly, forthcoming
Abstract:
Several studies have identified inconsistencies between “stated” interpersonal attitudes and those “revealed” after an interaction. The authors used the speed-dating paradigm to examine stated and revealed attitudes in ingroup preferences among Asian American subgroups (Chinese, Korean, Vietnamese, and Filipino Americans). Young single Asian Americans (n = 198) reported preferences for dating different ethnicities and went on speed dates, after which they could offer second dates to their partners. As expected, all four ethnic subgroups showed clear ingroup biases in stated preferences. Ingroup bias in revealed preferences (measured through date offers and ratings of partners’ mate desirability), however, were minimal. At the individual level, stated ingroup preferences did not significantly predict revealed ingroup preferences. In summary, among young Asian Americans, ingroup preferences may not hold in an interactive scenario. The findings suggest that in the presence of personal cues provided through a brief interaction, people may be less prone to make judgments on the basis of ethnicity, even when consequences extend beyond the laboratory. Furthermore, mechanisms for selecting a partner may differ in “hot” (affective) versus “cold” (cognitive) states.
First Impressions of Personality Traits From Body Shapes
Ying Hu et al.
Psychological Science, forthcoming
Abstract:
People infer the personalities of others from their facial appearance. Whether they do so from body shapes is less studied. We explored personality inferences made from body shapes. Participants rated personality traits for male and female bodies generated with a three-dimensional body model. Multivariate spaces created from these ratings indicated that people evaluate bodies on valence and agency in ways that directly contrast positive and negative traits from the Big Five domains. Body-trait stereotypes based on the trait ratings revealed a myriad of diverse body shapes that typify individual traits. Personality-trait profiles were predicted reliably from a subset of the body-shape features used to specify the three-dimensional bodies. Body features related to extraversion and conscientiousness were predicted with the highest consensus, followed by openness traits. This study provides the first comprehensive look at the range, diversity, and reliability of personality inferences that people make from body shapes.
The Relationship between Age and Facial Asymmetry
Olivia Linden et al.
Plastic and Reconstructive Surgery, November 2018, Pages 1145–1152
Results: The authors imaged 191 volunteers with an average age of 26.7 ± 22.2 years (range, 0.3 to 88 years). Root-mean-square deviation of facial symmetry clustered between 0.4 and 1.3 mm (mean, 0.8 ± 0.2 mm). The authors found a significant positive correlation between increasing age and asymmetry (p < 0.001; r = 0.66). The upper, middle, and lower facial third’s average root-mean-square deviations were 0.5 ± 0.2 mm (range, 0.2 to 1.2 mm), 0.6 ± 0.2 mm (range, 0.2 to 1.4 mm), and 0.6 ± 0.2 mm (range, 0.2 to 1.2 mm), respectively. Asymmetry also increased with age across all facial thirds (p < 0.001).
Conclusions: Facial asymmetry increases with age in each facial third, with a greater asymmetry and increase in asymmetry in the lower two-thirds. Contributing factors may include asymmetric skeletal remodeling along with differential deflation and descent of the soft tissues. The observed correlation between increasing facial asymmetry and age may be a useful guide in plastic surgery to produce age-matched features.