Rodrigo A. Cárdenas

Women's attractiveness changes with estradiol and progesterone across the ovulatory cycle

In many species, females are more sexually attractive to males near ovulation. Some evidence suggests a similar pattern in humans, but methodological limitations prohibit firm conclusions at present, and information on physiological mechanisms underlying any such pattern is lacking. In 202 normally-cycling women, we explored whether womens attractiveness changed over the cycle as a function of two likely candidates for mediating these changes: estradiol and progesterone. We scheduled women to attend one session during the late follicular phase and another during the mid-luteal phase. At each session, facial photographs, voice recordings and saliva samples were collected. All photographs and voice recordings were subsequently rated by men for attractiveness and by women for flirtatiousness and attractiveness to men. Saliva samples were assayed for estradiol and progesterone. We found that progesterone and its interaction with estradiol negatively predicted vocal attractiveness and overall (facial plus vocal) attractiveness to men. Progesterone also negatively predicted womens facial attractiveness to men and female-rated facial attractiveness, facial flirtatiousness and vocal attractiveness, but not female-rated vocal flirtatiousness. These results strongly suggest a pattern of increased attractiveness during peak fertility in the menstrual cycle and implicate estradiol and progesterone in driving these changes.

Sexual selection on male vocal fundamental frequency in humans and other anthropoids

In many primates, including humans, the vocalizations of males and females differ dramatically, with male vocalizations and vocal anatomy often seeming to exaggerate apparent body size. These traits may be favoured by sexual selection because low-frequency male vocalizations intimidate rivals and/or attract females, but this hypothesis has not been systematically tested across primates, nor is it clear why competitors and potential mates should attend to vocalization frequencies. Here we show across anthropoids that sexual dimorphism in fundamental frequency (F0) increased during evolutionary transitions towards polygyny, and decreased during transitions towards monogamy. Surprisingly, humans exhibit greater F0 sexual dimorphism than any other ape. We also show that low-F0 vocalizations predict perceptions of mens dominance and attractiveness, and predict hormone profiles (low cortisol and high testosterone) related to immune function. These results suggest that low male F0 signals condition to competitors and mates, and evolved in male anthropoids in response to the intensity of mating competition.

Fulfilling desire: Evidence for negative feedback between men's testosterone, sociosexual psychology, and sexual partner number

Across human societies and many nonhuman animals, males have greater interest in uncommitted sex (more unrestricted sociosexuality) than do females. Testosterone shows positive associations with male-typical sociosexual behavior in nonhuman animals. Yet, it remains unclear whether the human sex difference in sociosexual psychology (attitudes and desires) is mediated by testosterone, whether any relationships between testosterone and sociosexuality differ between men and women, and what the nature of these possible relationships might be. In studies to resolve these questions, we examined relationships between salivary testosterone concentrations and sociosexual psychology and behavior in men and women. We measured testosterone in all men in our sample, but only in those women taking oral contraception (OC-using women) in order to reduce the influence of ovulatory cycle variation in ovarian hormone production. We found that OC-using women did not differ from normally-ovulating women in sociosexual psychology or behavior, but that circulating testosterone mediated the sex difference in human sociosexuality and predicted sociosexual psychology in men but not OC-using women. Moreover, when sociosexual psychology was controlled, mens sociosexual behavior (number of sexual partners) was negatively related to testosterone, suggesting that testosterone drives sociosexual psychology in men and is inhibited when those desires are fulfilled. This more complex relationship between androgens and male sexuality may reconcile some conflicting prior reports.

Voice change as a new measure of male pubertal timing: a study among Bolivian adolescents.

Background: Age at menarche is often used to measure maturational tempo in girls. Unfortunately, no parallel marker exists for boys. It is suggested that voice change has a number of advantages as a marker of the timing and degree of male pubertal development. Aim: Traditional auxological methods are applied to voice change in order to compare differential development both between (males vs females; Tsimane vs North American; better vs worse condition) and within (voice vs height; fundamental frequency vs formant structure) populations. Subjects and methods: Fundamental and formant frequencies, as well as height and weight, were measured for 172 Tsimane males and females, aged 8–23. Participants were assigned to ‘better’ or ‘worse’ condition based on a median split of height-for-age and weight-for-age z-scores. Results: Results support dramatic vocal changes in males. Peak voice change among Tsimane male adolescents occurs∼1 year later than in an age-matched North American sample. Achieved adult male voices are also higher in the Tsimane. Tsimane males in worse condition experience voice change more than 1 year later than Tsimane males in better condition. Conclusion: Voice change has a number of attractive features as a marker of male pubertal timing including its methodological and technical simplicity as well as its social salience to group members.

How Well Do Men's Faces and Voices Index Mate Quality and Dominance?

Previous studies have used self-ratings or strangers’ ratings to assess men’s attractiveness and dominance, attributes that have likely affected men’s access to mates throughout human evolution. However, attractiveness and dominance include more than isolated impressions; they incorporate knowledge gained through social interaction. We tested whether dominance and attractiveness assessed by acquaintances can be predicted from (1) strangers’ ratings made from facial photographs and vocal clips and (2) self-ratings. Two university social fraternities, their socially affiliated sororities, and independent raters evaluated men’s short- and long-term attractiveness, fighting ability, and leadership ability. Ratings made by unfamiliar men using faces, but not voices, predicted acquaintance-rated fighting and leadership ability, whereas ratings made by unfamiliar women from faces and voices predicted acquaintance-rated short- and long-term attractiveness. Except for leadership, self-ratings aligned with peers’ evaluations. These findings support the conclusion that faces and voices provide valuable information about dominance and mate quality.

Masculine Men Articulate Less Clearly

In previous research, acoustic characteristics of the male voice have been shown to signal various aspects of mate quality and threat potential. But the human voice is also a medium of linguistic communication. The present study explores whether physical and vocal indicators of male mate quality and threat potential are linked to effective communicative behaviors such as vowel differentiation and use of more salient phonetic variants of consonants. We show that physical and vocal indicators of male threat potential, height and formant position, are negatively linked to vowel space size, and that height and levels of circulating testosterone are negatively linked to the use of the aspirated variant of the alveolar stop consonant /t/. Thus, taller, more masculine men display less clarity in their speech and prefer phonetic variants that may be associated with masculine attributes such as toughness. These findings suggest that vocal signals of men’s mate quality and/or dominance are not confined to the realm of voice acoustics but extend to other aspects of communicative behavior, even if this means a trade-off with speech patterns that are considered communicatively advantageous, such as clarity and indexical cues to higher social class.

The face of female dominance: Women with dominant faces have lower cortisol

The human face displays a wealth of information, including information about dominance and fecundity. Dominance and fecundity are also associated with lower concentrations of the stress hormone cortisol, suggesting that cortisol may negatively predict facial dominance and attractiveness. We digitally photographed 61 womens faces, had these images rated by men and women for dominance, attractiveness, and femininity, and explored relationships between these perceptions and womens salivary cortisol concentrations. In a first study, we found that women with more dominant-appearing, but not more attractive, faces had lower cortisol levels. These associations were not due to age, ethnicity, time since waking, testosterone, or its interaction with cortisol. In a second study, composite images of women with low cortisol were perceived as more dominant than those of women with high cortisol significantly more often than chance by two samples of viewers, with a similar but non-significant trend in a third sample. However, data on perceptions of attractiveness were mixed; low-cortisol images were viewed as more attractive by two samples of US viewers and as less attractive by a sample of Mexican viewers. Our results suggest that having a more dominant-appearing face may be associated with lower stress and hence lower cortisol in women, and provide further evidence regarding the information content of the human face.

Are only infants held more often on the left? If so, why? Testing the attention-emotion hypothesis with an infant, a vase, and two chimeric tests, one “emotional,” one not

ABSTRACT Most adults, especially women, hold infants and dolls but not books or packages on the left side. One reason may be that attention is more often leftward in response to infants, unlike emotionally neutral objects like books and packages. Womens stronger bias may reflect greater responsiveness to infants. Previously, we tested the attention hypothesis by comparing womens side-of-hold of a doll, book, and package with direction-of-attention on the Chimeric Faces Test (CFT) [Harris, L. J., Cárdenas, R. A., Spradlin, Jr., M. P., & Almerigi, J. B. (2010). Why are infants held on the left? A test of the attention hypothesis with a doll, a book, and a bag. Laterality: Asymmetries of Body, Brain and Cognition, 15(5), 548–571. doi:10.1080/13576500903064018]. Only the doll was held more often to the left, and only for the doll were side-of-hold and CFT scores related, with left-holders showing a stronger left-attention bias than right-holders. In the current study, we tested men and women with a doll and the CFT along with a vase as a neutral object and a “non-emotional” chimeric test. Again, only the doll was held more often to the left, but now, although both chimeric tests showed left-attention biases, scores were unrelated to side-of-hold. Nor were there sex differences. The results support left-hold selectivity but not the attention hypothesis, with or without the element of emotion. They also raise questions about the contribution of sex-of-holder. We conclude with suggestions for addressing these issues.