A sex difference in the context-sensitivity of dominance perceptions

Although dominance perceptions are thought to be important for effective social interaction, their primary function is unclear. One possibility is that they simply function to identify individuals who are capable of inflicting substantial physical harm, so that the perceiver can respond to them in ways that maximize their own physical safety. Another possibility is that they are more specialized, functioning primarily to facilitate effective direct (i.e., violent) intrasexual competition for mates, particularly among men. Here we used a priming paradigm to investigate these two possibilities. Facial cues of dominance were more salient to women after they had been primed with images of angry men, a manipulation known to activate particularly strong self-protection motivations, than after they had been primed with images of angry women or smiling individuals of either sex. By contrast, dominance cues were more salient to men after they had been primed with images of women than when they had been primed with images of men (regardless of the emotional expressions displayed), a manipulation previously shown to alter men's impressions of the sex ratio of the local population. Thus, men's dominance perceptions appear to be specialized for effective direct competition for mates, while women's dominance perceptions may function to maximize their physical safety more generally. Together, our results suggest that men's and women's dominance perceptions show different patterns of context-sensitivity and, potentially, shed new light on the routes through which violence and intrasexual competition have shaped dominance perceptions

Voice parameters predict sex-specific body morphology in men and women

Studies of several mammalian species confirm that formant frequencies (vocal tract resonances) predict height and weight better than does fundamental frequency (F0, perceived as pitch) in same-sex adults due to differential anatomical constraints. However, our recent meta-analysis (Pisanski et al., 2014, Animal Behaviour, 95, 89–99) indicated that formants and F0 could explain no more than 10% and 2% of the variance in human height, respectively, controlling for sex and age. Here, we examined whether other voice parameters, many of which are affected by sex hormones, can indicate additional variance in human body size or shape, and whether these relationships differ between the sexes. Using a cross-cultural sample of 700 men and women, we examined relationships among 19 voice parameters (minimum–maximum F0, mean F0, F0 variability, formant-based vocal tract length estimates, shimmer, jitter, harmonics-to-noise ratio) and eight indices of body size or shape (height, weight, body mass index, hip, waist and chest circumferences, waist-to-hip ratio, chest-to-hip ratio). Our results confirm that formant measures explain the most variance in heights and weights of men and women, whereas shimmer, jitter and harmonics-to-noise ratio do not indicate height, weight or body mass index in either sex. In contrast, these perturbation and noise parameters, in addition to F0 range and variability, explained more variance in body shape than did formants or mean F0, particularly among men. Shimmer or jitter explained the most variance in men's hip circumferences (12%) and chest-to-hip ratios (6%), whereas harmonics-to-noise ratio and formants explained the most variance in women's waist-to-hip ratios (11%), and significantly more than in men's waist-to-hip ratios. Our study represents the most comprehensive analysis of vocal indicators of human body size to date and offers a foundation for future research examining the hormonal mechanisms of voice production in humans and perceptual playback experiments

Sensory exploitation, sexual dimorphism, and human voice pitch

Selection for low male voice pitch is generally assumed to occur because it is a valid cue of formidability. Here we summarize recent empirical challenges to this hypothesis. We also outline an alternative account in which selection for low male voice pitch is a byproduct of sensory exploitation

Changes in salivary estradiol predict changes in women’s preferences for vocal masculinity

Although many studies have reported that women’s preferences for masculine physical characteristics in men change systematically during the menstrual cycle, the hormonal mechanisms underpinning these changes are currently poorly understood. Previous studies investigating the relationships between measured hormone levels and women’s masculinity preferences tested only judgments of men’s facial attractiveness. Results of these studies suggested that preferences for masculine characteristics in men’s faces were related to either women’s estradiol or testosterone levels. To investigate the hormonal correlates of within-woman variation in masculinity preferences further, here we measured 62 women’s salivary estradiol, progesterone, and testosterone levels and their preferences for masculine characteristics in men’s voices in five weekly test sessions. Multilevel modeling of these data showed that changes in salivary estradiol were the best predictor of changes in women’s preferences for vocal masculinity. These results complement other recent research implicating estradiol in women’s mate preferences, attention to courtship signals, sexual motivation, and sexual strategies, and are the first to link women’s voice preferences directly to measured hormone levels

Changes in salivary estradiol predict changes in women’s preferences for vocal masculinity

Although many studies have reported that women’s preferences for masculine physical characteristics in men change systematically during the menstrual cycle, the hormonal mechanisms underpinning these changes are currently poorly understood. Previous studies investigating the relationships between measured hormone levels and women’s masculinity preferences tested only judgments of men’s facial attractiveness. Results of these studies suggested that preferences for masculine characteristics in men’s faces were related to either women’s estradiol or testosterone levels. To investigate the hormonal correlates of within-woman variation in masculinity preferences further, here we measured 62 women’s salivary estradiol, progesterone, and testosterone levels and their preferences for masculine characteristics in men’s voices in five weekly test sessions. Multilevel modeling of these data showed that changes in salivary estradiol were the best predictor of changes in women’s preferences for vocal masculinity. These results complement other recent research implicating estradiol in women’s mate preferences, attention to courtship signals, sexual motivation, and sexual strategies, and are the first to link women’s voice preferences directly to measured hormone levels

Symmetry is related to sexual dimorphism in faces: data across culture and species

BACKGROUND: Many animals both display and assess multiple signals. Two prominently studied traits are symmetry and sexual dimorphism, which, for many animals, are proposed cues to heritable fitness benefits. These traits are associated with other potential benefits, such as fertility. In humans, the face has been extensively studied in terms of attractiveness. Faces have the potential to be advertisements of mate quality and both symmetry and sexual dimorphism have been linked to the attractiveness of human face shape. METHODOLOGY/PRINCIPAL FINDINGS: Here we show that measurements of symmetry and sexual dimorphism from faces are related in humans, both in Europeans and African hunter-gatherers, and in a non-human primate. Using human judges, symmetry measurements were also related to perceived sexual dimorphism. In all samples, symmetric males had more masculine facial proportions and symmetric females had more feminine facial proportions. CONCLUSIONS/SIGNIFICANCE: Our findings support the claim that sexual dimorphism and symmetry in faces are signals advertising quality by providing evidence that there must be a biological mechanism linking the two traits during development. Such data also suggests that the signalling properties of faces are universal across human populations and are potentially phylogenetically old in primates

No evidence that averaging voices influences attractiveness

Vocal attractiveness influences important social outcomes. While most research on the acoustic parameters that influence vocal attractiveness has focused on the possible roles of sexually dimorphic characteristics of voices, such as fundamental frequency (i.e., pitch) and formant frequencies (i.e., a correlate of body size), other work has reported that increasing vocal averageness increases attractiveness. Here we investigated the roles these three characteristics play in judgments of the attractiveness of male and female voices. In Study 1, we found that increasing vocal averageness significantly decreased distinctiveness ratings, demonstrating that participants could detect manipulations of vocal averageness in this stimulus set and using this testing paradigm. However, in Study 2, we found no evidence that increasing averageness significantly increased attractiveness ratings of voices. In Study 3, we found that fundamental frequency was negatively correlated with male vocal attractiveness and positively correlated with female vocal attractiveness. By contrast with these results for fundamental frequency, vocal attractiveness and formant frequencies were not significantly correlated. Collectively, our results suggest that averageness may not necessarily significantly increase attractiveness judgments of voices and are consistent with previous work reporting significant associations between attractiveness and voice pitch

No evidence that averaging voices influences attractiveness

Vocal attractiveness influences important social outcomes. While most research on the acoustic parameters that influence vocal attractiveness has focused on the possible roles of sexually dimorphic characteristics of voices, such as fundamental frequency (i.e., pitch) and formant frequencies (i.e., a correlate of body size), other work has reported that increasing vocal averageness increases attractiveness. Here we investigated the roles these three characteristics play in judgments of the attractiveness of male and female voices. In Study 1, we found that increasing vocal averageness significantly decreased distinctiveness ratings, demonstrating that participants could detect manipulations of vocal averageness in this stimulus set and using this testing paradigm. However, in Study 2, we found no evidence that increasing averageness significantly increased attractiveness ratings of voices. In Study 3, we found that fundamental frequency was negatively correlated with male vocal attractiveness and positively correlated with female vocal attractiveness. By contrast with these results for fundamental frequency, vocal attractiveness and formant frequencies were not significantly correlated. Collectively, our results suggest that averageness may not necessarily significantly increase attractiveness judgments of voices and are consistent with previous work reporting significant associations between attractiveness and voice pitch

No evidence that averaging voices influences attractiveness

Vocal attractiveness influences important social outcomes. While most research on the acoustic parameters that influence vocal attractiveness has focused on the possible roles of sexually dimorphic characteristics of voices, such as fundamental frequency (i.e., pitch) and formant frequencies (i.e., a correlate of body size), other work has reported that increasing vocal averageness increases attractiveness. Here we investigated the roles these three characteristics play in judgments of the attractiveness of male and female voices. In Study 1, we found that increasing vocal averageness significantly decreased distinctiveness ratings, demonstrating that participants could detect manipulations of vocal averageness in this stimulus set and using this testing paradigm. However, in Study 2, we found no evidence that increasing averageness significantly increased attractiveness ratings of voices. In Study 3, we found that fundamental frequency was negatively correlated with male vocal attractiveness and positively correlated with female vocal attractiveness. By contrast with these results for fundamental frequency, vocal attractiveness and formant frequencies were not significantly correlated. Collectively, our results suggest that averageness may not necessarily significantly increase attractiveness judgments of voices and are consistent with previous work reporting significant associations between attractiveness and voice pitch

The role of valence, dominance, and pitch in social perceptions of artificial intelligence (AI) conversational agents' voices

There is growing concern that artificial intelligence (AI) conversational agents (e.g., Siri, Alexa) reinforce voice-based social stereotypes. Because little is known about social perceptions of conversational agents’ voices, we investigated the perceptual dimensions that underpin social perceptions of these synthetic voices and the role that acoustic parameters play in these perceptions. In Study 1 (N = 504), Principal Component Analysis of ratings of synthetic voices on a range of traits (trustworthiness, emotional stability, responsibility, sociability, caringness, attractiveness, intelligence, confidence, weirdness, unhappiness, meanness, aggressiveness, dominance, competence, age, masculinity, femininity) suggested that social perceptions of synthetic voices are underpinned by Valence and Dominance components that are highly similar to those previously reported for natural human stimuli. Study 1 also found that scores on the Dominance component were strongly and negatively related to voice pitch. Study 2 (N = 160) found that experimentally manipulating pitch in synthetic voices directly influenced perceptions of their dominance and aggressiveness, but not their competence or trustworthiness. Collectively, these results suggest that greater consideration of the role that voice pitch plays in dominance-related social perceptions when designing conversational agents will be effective in controlling stereotypic perceptions of their voices and the downstream consequences of those perceptions