Do men with more masculine voices have better immunocompetence?

The human voice is often considered to be a secondary sexual characteristic that signals underlying information about the immunocompetence of the speaker (i.e. the immunocompetence handicap hypothesis; ICHH). However, no studies have yet shown a relationship between vocal characteristics and biomarkers of immune function or self-reported health. In a sample of 108 men, we examined correlations between masculine vocal characteristics [i.e. relatively low fundamental frequency (F₀), low F₀ variability (F₀-SD), low formant position (P_f), and high vocal tract length (VTL)] in relation to salivary immunoglobulin-A (sIgA; a marker of mucosal immunity), testosterone (T), and well-validated measures of self-reported health status. Results showed that sIgA correlated with masculinized F₀, P_f, and VTL. Self-report health correlated with masculinized P_f and VTL. Anticipated future health correlated negatively with F₀-SD and sick role propensity (less interference of illness in daily life) correlated positively with VTL. Perceived susceptibility to infection correlated with more feminized F₀ and F₀-SD. Our results demonstrated a small relationship between men's vocal characteristics and one putative indicator of mucosal immunity along with self-identified health status. We suggest that more research is warranted to determine whether the masculinity of men's voices may serve as an indicator of their phenotypic quality.     

Can listeners assess men's self-reported health from their voice?

Men's voices may provide cues to overall condition; however, little research has assessed whether health status is reliably associated with perceivable voice parameters. In Study 1, we investigated whether listeners could classify voices belonging to men with either relatively lower or higher self-reported health. Participants rated voices for speaker health, disease likelihood, illness frequency, and symptom severity, as well as attractiveness (women only) and dominance (men only). Listeners' were mostly unable to judge the health of male speakers from their voices; however, men rated the voices of men with better self-reported health as sounding more dominant. In Study 2, we tested whether men's vocal parameters (fundamental frequency mean and variation, apparent vocal tract length, and harmonics-to-noise ratio) and aspects of their self-reported health predicted listeners' health and disease resistance ratings of those voices. Speakers' fundamental frequency (f_o) negatively predicted ratings of health. However, speakers' self-reported health did not predict ratings of health made by listeners. In Study 3, we investigated whether separately manipulating two sexually dimorphic vocal parameters—f_o and apparent vocal tract length (VTL)—affected listeners' health ratings. Listeners rated men's voices with lower f_o (but not VTL) as healthier, supporting findings from Study 2. Women rated voices with lower f_o and VTL as more attractive, and men rated them as more dominant. Thus, while both VTL and f_o affect dominance and attractiveness judgments, only f_o appears to affect health judgments. Results of the above studies suggest that, although listeners assign higher health ratings to speakers with more masculine f_o, these ratings may not be accurate at tracking speakers' self-rated health.     

Soprano singing in gibbons

Diversifications in primate vocalization, including human speech, are believed to reflect evolutionary modifications in vocal anatomy and physiology. Gibbon song is acoustically unique, comprising loud, melodious, penetrating pure tone‐like calls. In a white‐handed gibbon, Hylobates lar, the fundamental frequency (f₀) of song sounds is amplified distinctively from the higher harmonics in normal air. In a helium‐enriched atmosphere, f₀ does not shift, but it is significantly suppressed and 2f₀ is emphasized. This implies that the source is independent of the resonance filter of the supralaryngeal vocal tract (SVT) in gibbons, in contrast to musical wind instruments, in which the filter primarily determines f₀. Acoustic simulation further supported that gibbons' singing is produced analogously to professional human soprano singing, in which a precise tuning of the first formant (F₁) of the SVT to f₀ amplifies exclusively the f₀ component of the source. Thus, in gibbons, as in humans, dynamic control over the vocal tract configuration, rather than anatomical modifications, has been a dominant factor in determining call structure. The varied dynamic movements were adopted in response to unique social and ecological pressures in gibbons, allowing monogamous gibbons to produce pure‐tonal melodious songs in the dense tropical forests with poor visibility. Am J Phys Anthropol, 2012. © 2012 Wiley Periodicals, Inc.     

The effect of phonation into a straw on the vocal tract adjustments and formant frequencies. A preliminary MRI study on a single subject completed with acoustic results

Phonation into a straw is used in voice training and therapy. This study investigated its’ effects on the vocal tract adjustments.Magnetic resonance images were taken from one female phonating first on [a:], then into a plastic drinking straw and then again on [a:]. Acoustic samples were recorded from her and 10 other females. The samples were analyzed for fundamental frequency, sound pressure level (SPL), five lowest formant frequencies (F₁–F₅) and SPL of the speaker's formant cluster range (2.5–4.5 kHz).During and after phonation into a straw, the midsagittal area of the vocal tract increased and the velar closure improved. The ratio of the transversal area of the lower pharynx over that of the epilarynx increased both during (27%) and after the straw (20%). The overall SPL and the SPL of the speaker's formant cluster increased. The frequencies of F₂, F₄ and F₅ decreased, while F₃ increased. The distances between F₄ and F₃ and F₅ and F₄ decreased by 49%. For the 10 subjects, F₃ increased, F₄ decreased and the distance between F₃ and F₄ decreased significantly.The results suggest that exercising with a straw helps establishing a speaker's formant cluster, which increases loudness and thus improves vocal economy.     

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.     

Inheritance of Cry1Ac resistance and associated biological traits in the cotton bollworm, Helicoverpa armigera (Lepidoptera: Noctuidae)

The analysis of reciprocal genetic crosses between resistant Helicoverpa armigera strain (BH-R) (227.9-fold) with susceptible Vadodara (VA-S) strain showed dominance (h) of 0.65-0.89 and degree of dominance (D) of 0.299-0.782 suggesting Cry1Ac resistance as a semi-dominant trait. The D and h values of F₁ hybrids of female resistant parent were higher than female susceptible parent, showing maternally enhanced dominance of Cry1Ac resistance. The progeny of F₂ crosses, backcrosses of F₁ hybrid with resistant BH-R parent did not differ significantly in respect of mortality response with resistant parent except for backcross with female BH-R and male of F₁ (BH-R × VA-S) cross, suggesting dominant inheritance of Cry1Ac resistance. Evaluation of some biological attributes showed that larval and pupal periods of progenies of reciprocal F₁ crosses, backcrosses and F₂ crosses were either at par with resistant parent or lower than susceptible parent on treated diet (0.01 μg/g). The susceptible strain performed better in terms of pupation and adult formation than the resistant strain on untreated diet. In many backcrosses and F₂ crosses, Cry1Ac resistance favored emergence of more females than males on untreated diet. The normal larval period and the body weight (normal larval growth) were the dominant traits associated with susceptible strain as contrast to longer larval period and the lower body weight (slow growth) associated with resistance trait. Further, inheritance of larval period in F₂ and backcross progeny suggested existence of a major resistant gene or a set of tightly linked loci associated with Cry1Ac sensitivity.     

Mating context and menstrual phase affect women's preferences for male voice pitch

Fundamental frequency (F₀) is the vocal acoustic parameter closest to what we perceive as pitch. Men speak at a lower F₀ than do women, even controlling for body size. Although the developmental and anatomical reasons for this sex difference are known, the evolutionary reasons are not. By examining fertility-related variation in women's preferences for men's voices, the present study tests the hypothesis that female choice for good genes influenced the evolution of male voice pitch (VP). Unlike previous correlational studies that did not consider the effects of menstrual phase and mating context on women's preferences for male VP, the present study includes these variables and utilizes experimental pitch (P) manipulations. Results indicate that low VP is preferred mainly in short-term mating contexts rather than in long-term, committed ones, and this mating context effect is greatest when women are in the fertile phase of their ovulatory cycles. Moreover, lower male F₀ correlated with higher self-reported mating success. These findings are consistent with the hypothesis that an association between low male VP and heritable fitness led to the evolution of the observed patterns in women's P preferences and men's mating success and that these patterns influenced the evolution of low VP in men. However, alternative explanations are considered.     

Vocal and visual attractiveness are related in women

We investigated the relation between visual and vocal attractiveness in women as judged by men. We recorded 34 women speaking four vowels and measured the peak frequency, the first five harmonic frequencies, the first five formant frequencies and formant dispersion. The women were also photographed (head shot), several body measures were taken and their ages were recorded. The voices were played to male judges who were asked to assess the women's age and vocal attractiveness from the recording. The men were then asked to assess the attractiveness of the photographs. Men were in strong agreement on which was an attractive voice and face; and women with attractive faces had attractive voices. Higher-frequency voices were assessed as being more attractive and as belonging to younger women (the lowest frequency produced is a good indicator of age in women in general). Larger women had lower voices and were judged as having less attractive faces and voices. Taller women had narrower formant dispersion as predicted. The results imply that different measures of attractiveness are in agreement and signal similar qualities, such as female age, body size and possibly hormonal profile. Copyright 2003 Published by Elsevier Science Ltd on behalf of The Association for the Study of Animal Behaviour.      

The relative importance of intra- and intersexual selection on human male sexually dimorphic traits

Recent evidence suggests that in sexual selection on human males, intrasexual competition plays a larger role than female choice. In a sample of men (N?=?164), we sought to provide further evidence on the effects of men's physical dominance and sexual attractiveness on mating success and hence in sexual selection. Objective measures and subjective ratings of male sexually dimorphic traits purportedly under sexual selection (height, vocal and facial masculinity, upper body size from 3D scans, physical strength, and baseline testosterone) and observer perceptions of physical dominance and sexual attractiveness based on self-presentation video recordings were assessed and associated with mating success (sociosexual behaviour and number of potential conceptions) in a partly longitudinal design. Results from structural equation models and selection analyses revealed that physical dominance, but not sexual attractiveness, predicted mating success. Physical dominance mediated associations of upper body size, physical strength, as well as vocal and facial physical dominance and attractiveness with mating success. These findings thus suggest a greater importance of intrasexual competition than female choice in human male sexual selection.     

Young,formidable men show greater sensitivity to facial cues of dominance

There is considerable evidence that human male faces contain honest, detectable cues to their physical dominance, which are related to their objective facial masculinity. As such, some have argued that the extent to which observers' rate masculinised male faces as appearing more physically dominant is a useful measure of their ability to detect cues of dominance and threat in other men. We found across 3 studies (total n = 272) that younger, taller, and stronger men showed greater sensitivity to facial cues of dominance. Additionally, participants were more likely to associate younger than older masculinised faces with physical dominance. Self-perceived social dominance did not moderate perceptions. These results contrast with previous work which found that shorter, less socially dominant men had greater ability to detect facial cues of dominance. We propose the hypothesis that younger, more formidable males show greater sensitivity to facial cues of dominance as they are more likely to engage in violent intrasexual competition.     

The joint effects of selection and dominance on the QST - FST contrast

Q_ST measures the differentiation of quantitative traits between populations. It is often compared to F_ST, which measures population differentiation at neutral marker loci due to drift, migration, and mutation. When Q_ST is different from F_ST, it is usually taken as evidence that selection has either restrained or accelerated the differentiation of the quantitative trait relative to neutral markers. However, a number of other factors such as inbreeding, dominance, and epistasis may also affect the Q_ST − F_ST contrast. In this study, we examine the effects of dominance, selection, and inbreeding on Q_ST − F_ST. We compare Q_ST with F_ST at selected and neutral loci for populations at equilibrium between selection, drift, mutation, and migration using both analytic and simulation approaches. Interestingly, when divergent selection is acting on a locus, inbreeding and dominance generally inflate Q_ST relative to F_ST when they are both measured at the quantitative locus at equilibrium. As a consequence, dominance is unlikely to hide the signature of divergent selection on the Q_ST − F_ST contrast. However, although in theory dominance and inbreeding affect the expectation for Q_ST − F_ST, of most concern is the very large variance in both Q_ST and F_ST, suggesting that we should be cautious in attributing small differences between Q_ST and F_ST to selection.     

Sexual selection for low male voice pitch among Amazonian forager-horticulturists

Pitch is the most perceptually salient feature of the voice, yet it is approximately five standard deviations lower in men than in women, a degree of sexual dimorphism exceeding that of all extant nonhuman apes. Evidence from Western samples suggests that low-frequency vocalizations may have augmented male mating success ancestrally by intimidating competitors and/or attracting mates. However, data are lacking from small-scale societies. We therefore investigated sexual selection on male pitch (measured by fundamental frequency, f_o) in a population of Bolivian forager-horticulturists, the Tsimané. We found that experimentally lowering f_o in audio clips of men speaking increased perceptions of fighting ability but did not affect perceptions of prestige and decreased their attractiveness to women. Further, men with lower speaking f_o reported higher numbers of offspring, and this was mediated by the reproductive rates of men's wives, suggesting that men with lower f_o achieved higher reproductive success by having access to more fertile mates. These results thus provide new evidence that men's f_o has been shaped by intrasexual competition.     

Dependence of the perception of emotional information of speech on the acoustic parameters of the stimulus in children of various ages

The effect on the perception of the emotional prosody of a vocal signal of the acoustic parameters of the stimulus in children of various ages (7–10, 11–13, and 14–17 years) was studied. Considerable differences in recognition of positive and negative valences of the vocal signal against the background of noise and in its absence were demonstrated. The ontogenetic specific features of the dependence of recognition of the emotional valence on the acoustic parameters of a vocal signal were determined. The most important acoustic characters (the fundamental frequency F0 and the frequency of the first formant F1) that ensure the perception of the emotional prosody of a vocal signal against the background of noise at different age stages were found.     

Effect of deuterium oxide on contraction characteristics and ATPase activity in glycerinated single rabbit skeletal muscle fibers

We studied the effect of deuterium oxide (D₂O) on contraction characteristics and ATPase activity of single glycerinated muscle fibers of rabbit psoas. D₂O increased the maximum isometric force P₀ by about 20%, while the force versus stiffness relation did not change appreciably. The maximum shortening velocity under zero load V_max did not change appreciably in D₂O, so that the force-velocity (P-V) curve was scaled depending on the value of P₀. The Mg-ATPase activity of the fibers during generation of steady isometric force P₀ was reduced by about 50% in D₂O. Based on the Huxley contraction model, these results can be accounted for in terms of D₂O-induced changes in the rate constants f₁ and g₁ for making and breaking actin-myosin linkages in the isometric condition, in such a way that f₁/(f₁+g₁) increases by about 20%, while (f₁+g₁) remains unchanged. The D₂O effect at the molecular level is discussed in connection with biochemical studies on actomyosin ATPase.     

Predictors of social dominance in the adult female golden hamster (Mesocricetus auratus)

Adult female golden hamsters exhibit smaller and less pigmented flank glands than do males. Nevertheless, as has been found in male hamsters, variations in these parameters of the flank glands correlate highly (r_s=0·78) with social rank attained in a group of four females. Ovariectomy and subsequent replacement with a graded series of testosterone propionate doses produces a directly related response in the flank gland and in the social rank attained in all-female groups (r_s=0·72). Body weight of females also correlates directly with social status (r_s=0·74), but, when body weight is held constant, social rank can still be predicted from measures of the flank gland. Oestrous-related fluctuations in aggressive behaviour of females did not alter dominance relationships.     

The evolved psychology of voice: evaluating interrelationships in listeners' assessments of the size,masculinity, and attractiveness of unseen speakers

A growing body of research has examined how voice characteristics advertise personal dimensions relevant in mate competition and mate choice. This work has centered on two key voice features, namely, fundamental frequency (F₀) and formants (Fn), and has consistently found that speakers with low F₀, low Fn, or both are rated as being larger, more masculine, and more attractive if men but less attractive if women. However, this consistency in listeners' perceptions is not matched by an equivalent consensus in how these mate-relevant dimensions are causally related or signaled by voice characteristics. Consequently, it is critical to test whether the strong correlations in listeners' perceptions reflect reliable causal relationships between these dimensions or, alternatively, whether they reflect some perceptual or cognitive nonindependence, for example, “what is large is masculine” and “what is small is feminine.” To test this latter possibility, we report detailed analyses of interdependence in listeners' ratings of perceived size, masculinity or femininity, and attractiveness of natural and manipulated voices of the opposite sex. We found strong correlations in listeners' ratings of all three dimensions, confirming past research. Principal component analysis corroborated these interrelationships but also revealed some independence in women's ratings of men's attractiveness and additional (but weaker) independence in men's ratings of women's size. We discuss possible implications for future research on the evolved psychology of voice and whether and how it reflects adaptive functional heuristics for discriminating mates.     

Vocal modulation during courtship increases proceptivity even in naive listeners

Speakers modulate their voice when talking to infants, but we know little about subtle variation in acoustic parameters during speech in adult social interactions. Because tests of perception of such variation are hampered by listeners' understanding of semantic content, studies often confine speech to enunciation of standard sentences, restricting ecological validity. Furthermore, apparent paralinguistic modulation in one language may be underpinned by specific parameters of that language. Here we circumvent these problems by recording speech directed to attractive or unattractive potential partners or competitors, and testing responses to these recordings by naive listeners, across both a Germanic (English) and a Slavic (Czech) language. Analysis of acoustic parameters indicates that men's voices varied F₀ most in speech towards potential attractive versus unattractive mates, while modulation of women's F₀ variability was more sensitive to competitors, with higher variability when those competitors were relatively attractive. There was striking similarity in patterns of social context-dependent F₀ variation across the two model languages, with both men's and women's voices varying most when responding to attractive individuals. Men's minimum pitch was lower when responding to attractive than unattractive women. For vocal modulation to be effective, however, it must be sufficiently detectable to promote proceptivity towards the speaker. We showed that speech directed towards attractive individuals was preferred by naive listeners of either language over speech by the same speaker to unattractive individuals, even when voices were stripped of several acoustic properties by low-pass filtering, which renders speech unintelligible. Our results suggest that modulating F₀ may be a critical parameter in human courtship, independently of semantic content.     

Generalization of the QST framework in hierarchically structured populations: Impacts of inbreeding and dominance

Q_ST is a differentiation parameter based on the decomposition of the genetic variance of a trait. In the case of additive inheritance and absence of selection, it is analogous to the genic differentiation measured on individual loci, F_ST. Thus, Q_ST?F_ST comparison is used to infer selection: selective divergence when Q_ST > F_ST, or convergence when Q_ST < F_ST. The definition of Q‐statistics was extended to two‐level hierarchical population structures with Hardy–Weinberg equilibrium. Here, we generalize the Q‐statistics framework to any hierarchical population structure. First, we developed the analytical definition of hierarchical Q‐statistics for populations not at Hardy–Weinberg equilibrium. We show that the Q‐statistics values obtained with the Hardy–Weinberg definition are lower than their corresponding F‐statistics when F_IS > 0 (higher when F_IS < 0). Then, we used an island model simulation approach to investigate the impact of inbreeding and dominance on the Q_ST?F_ST framework in a hierarchical population structure. We show that, while differentiation at the lower hierarchical level (Q_SR) is a monotonic function of migration, differentiation at the upper level (Q_RT) is not. In the case of additive inheritance, we show that inbreeding inflates the variance of Q_RT, which can increase the frequency of Q_RT > F_RT cases. We also show that dominance drastically reduces Q‐statistics below F‐statistics for any level of the hierarchy. Therefore, high values of Q‐statistics are good indicators of selection, but low values are not in the case of dominance.