Tennis grunts communicate acoustic cues to sex and contest outcome

Sounds like a fight: listeners can infer behavioural contexts from spontaneous nonverbal vocalisations

When we hear another person laugh or scream, can we tell the kind of situation they are in - for example, whether they are playing or fighting? Nonverbal expressions are theorised to vary systematically across behavioural contexts. Perceivers might be sensitive to these putative systematic mappings and thereby correctly infer contexts from others' vocalisations. Here, in two pre-registered experiments, we test the prediction that listeners can accurately deduce production contexts (e.g. being tickled, discovering threat) from spontaneous nonverbal vocalisations, like sighs and grunts. In Experiment 1, listeners (total n = 3120) matched 200 nonverbal vocalisations to one of 10 contexts using yes/no response options. Using signal detection analysis, we show that listeners were accurate at matching vocalisations to nine of the contexts. In Experiment 2, listeners (n = 337) categorised the production contexts by selecting from 10 response options in a forced-choice task. By analysing unbiased hit rates, we show that participants categorised all 10 contexts at better-than-chance levels. Together, these results demonstrate that perceivers can infer contexts from nonverbal vocalisations at rates that exceed that of random selection, suggesting that listeners are sensitive to systematic mappings between acoustic structures in vocalisations and behavioural contexts.

Origins Of Vocal-Entangled Gesture

Gestures during speaking are typically understood in a representational framework: they represent absent or distal states of affairs by means of pointing, resemblance, or symbolic replacement. However, humans also gesture along with the rhythm of speaking, which is amenable to a non-representational perspective. Such a perspective centers on the phenomenon of vocal-entangled gestures and builds on evidence showing that when an upper limb with a certain mass decelerates/accelerates sufficiently, it yields impulses on the body that cascade in various ways into the respiratory-vocal system. It entails a physical entanglement between body motions, respiration, and vocal activities. It is shown that vocal-entangled gestures are realized in infant vocal-motor babbling before any representational use of gesture develops. Similarly, an overview is given of vocal-entangled processes in non-human animals. They can frequently be found in rats, bats, birds, and a range of other species that developed even earlier in the phylogenetic tree. Thus, the origins of human gesture lie in biomechanics, emerging early in ontogeny and running deep in phylogeny.

Vocal modulation in human mating and competition

The human voice is dynamic, and people modulate their voices across different social interactions. This article presents a review of the literature examining natural vocal modulation in social contexts relevant to human mating and intrasexual competition. Altering acoustic parameters during speech, particularly pitch, in response to mating and competitive contexts can influence social perception and indicate certain qualities of the speaker. For instance, a lowered voice pitch is often used to exert dominance, display status and compete with rivals. Changes in voice can also serve as a salient medium for signalling a person's attraction to another, and there is evidence to support the notion that attraction and/or romantic interest can be distinguished through vocal tones alone. Individuals can purposely change their vocal behaviour in attempt to sound more attractive and to facilitate courtship success. Several findings also point to the effectiveness of vocal change as a mechanism for communicating relationship status. As future studies continue to explore vocal modulation in the arena of human mating, we will gain a better understanding of how and why vocal modulation varies across social contexts and its impact on receiver psychology. This article is part of the theme issue 'Voice modulation: from origin and mechanism to social impact (Part I)'.

Human voice pitch measures are robust across a variety of speech recordings: methodological and theoretical implications

Fundamental frequency (f_o), perceived as voice pitch, is the most sexually dimorphic, perceptually salient and intensively studied voice parameter in human nonverbal communication. Thousands of studies have linked human f_o to biological and social speaker traits and life outcomes, from reproductive to economic. Critically, researchers have used myriad speech stimuli to measure f_o and infer its functional relevance, from individual vowels to longer bouts of spontaneous speech. Here, we acoustically analysed f_o in nearly 1000 affectively neutral speech utterances (vowels, words, counting, greetings, read paragraphs and free spontaneous speech) produced by the same 154 men and women, aged 18-67, with two aims: first, to test the methodological validity of comparing f_o measures from diverse speech stimuli, and second, to test the prediction that the vast inter-individual differences in habitual f_o found between same-sex adults are preserved across speech types. Indeed, despite differences in linguistic content, duration, scripted or spontan--eous production and within-individual variability, we show that 42-81% of inter-individual differences in f_o can be explained between any two speech types. Beyond methodological implications, together with recent evidence that inter-individual differences in f_o are remarkably stable across the lifespan and generalize to emotional speech and nonverbal vocalizations, our results further substantiate voice pitch as a robust and reliable biomarker in human communication.

Individual differences in human voice pitch are preserved from speech to screams, roars and pain cries

Fundamental frequency (F0, perceived as voice pitch) predicts sex and age, hormonal status, mating success and a range of social traits, and thus functions as an important biosocial marker in modal speech. Yet, the role of F0 in human nonverbal vocalizations remains unclear, and given considerable variability in F0 across call types, it is not known whether F0 cues to vocalizer attributes are shared across speech and nonverbal vocalizations. Here, using a corpus of vocal sounds from 51 men and women, we examined whether individual differences in F0 are retained across neutral speech, valenced speech and nonverbal vocalizations (screams, roars and pain cries). Acoustic analyses revealed substantial variability in F0 across vocal types, with mean F0 increasing as much as 10-fold in screams compared to speech in the same individual. Despite these extreme pitch differences, sexual dimorphism was preserved within call types and, critically, inter-individual differences in F0 correlated across vocal types (r = 0.36-0.80) with stronger relationships between vocal types of the same valence (e.g. 38% of the variance in roar F0 was predicted by aggressive speech F0). Our results indicate that biologically and socially relevant indexical cues in the human voice are preserved in simulated valenced speech and vocalizations, including vocalizations characterized by extreme F0 modulation, suggesting that voice pitch may function as a reliable individual and biosocial marker across disparate communication contexts.

The Jena Speaker Set (JESS)-A database of voice stimuli from unfamiliar young and old adult speakers

Here we describe the Jena Speaker Set (JESS), a free database for unfamiliar adult voice stimuli, comprising voices from 61 young (18-25 years) and 59 old (60-81 years) female and male speakers uttering various sentences, syllables, read text, semi-spontaneous speech, and vowels. Listeners rated two voice samples (short sentences) per speaker for attractiveness, likeability, two measures of distinctiveness ("deviation"-based [DEV] and "voice in the crowd"-based [VITC]), regional accent, and age. Interrater reliability was high, with Cronbach's α between .82 and .99. Young voices were generally rated as more attractive than old voices, but particularly so when male listeners judged female voices. Moreover, young female voices were rated as more likeable than both young male and old female voices. Young voices were judged to be less distinctive than old voices according to the DEV measure, with no differences in the VITC measure. In age ratings, listeners almost perfectly discriminated young from old voices; additionally, young female voices were perceived as being younger than young male voices. Correlations between the rating dimensions above demonstrated (among other things) that DEV-based distinctiveness was strongly negatively correlated with rated attractiveness and likeability. By contrast, VITC-based distinctiveness was uncorrelated with rated attractiveness and likeability in young voices, although a moderate negative correlation was observed for old voices. Overall, the present results demonstrate systematic effects of vocal age and gender on impressions based on the voice and inform as to the selection of suitable voice stimuli for further research into voice perception, learning, and memory.

The pitch of babies' cries predicts their voice pitch at age 5

Voice pitch (fundamental frequency, F₀) is a key dimension of our voice that varies between sexes after puberty, and also among individuals of the same sex both before and after puberty. While a recent longitudinal study indicates that inter-individual differences in voice pitch remain stable in men during adulthood and may even be determined before puberty (Fouquet et al. 2016 R. Soc. open sci.3, 160395. (doi:10.1098/rsos.160395)), whether these differences emerge in infancy remains unknown. Here, using a longitudinal study design, we investigate the hypothesis that inter-individual differences in F₀ are already present in the cries of pre-verbal babies. While based on a small sample (n = 15), our results indicate that the F₀ of babies' cries at 4 months of age may predict the F₀ of their speech utterances at 5 years of age, explaining 41% of the inter-individual variance in voice pitch at that age in our sample. We also found that the right-hand ratio of the length of their index to ring finger (2D : 4D digit ratio), which has been proposed to constitute an index of prenatal testosterone exposure, was positively correlated with F₀ at both 4 months and 5 years of age. These findings suggest that a substantial proportion of between-individual differences in voice pitch, which convey important biosocial information about speakers, may partly originate in utero and thus already be present soon after birth.

Roar of a Champion: Loudness and Voice Pitch Predict Perceived Fighting Ability but Not Success in MMA Fighters

Historically, antagonistic interactions have been a crucial determinant of access to various fitness-affecting resources. In many vertebrate species, information about relative fighting ability is conveyed, among other things, by vocalization. Previous research found that men's upper-body strength can be assessed from voice. In the present study, we tested formidability perception of intimidating vocalization (roars) and a short utterance produced by amateur male MMA fighters attending the amateur European Championships in relation to their physical fitness indicators and fighting success. We also tested acoustic predictors of the perceived formidability. We found that body height, weight, and physical fitness failed to predict perceived formidability either from speech or from the roars. Similarly, there was no significant association between formidability of the roars and utterances and actual fighting success. Perceived formidability was predicted mainly by roars' and utterances' intensity and roars' harmonics-to-noise ratio and duration. Interestingly, fundamental frequency (F₀) predicted formidability ratings in both roars and utterances but in an opposite manner, so that low F₀ utterances but high F₀ roars were rated as more formidable. Our results suggest that formidability perception is primarily driven by intensity and duration of the vocalizations.

Human roars communicate upper-body strength more effectively than do screams or aggressive and distressed speech

Despite widespread evidence that nonverbal components of human speech (e.g., voice pitch) communicate information about physical attributes of vocalizers and that listeners can judge traits such as strength and body size from speech, few studies have examined the communicative functions of human nonverbal vocalizations (such as roars, screams, grunts and laughs). Critically, no previous study has yet to examine the acoustic correlates of strength in nonverbal vocalisations, including roars, nor identified reliable vocal cues to strength in human speech. In addition to being less acoustically constrained than articulated speech, agonistic nonverbal vocalizations function primarily to express motivation and emotion, such as threat, and may therefore communicate strength and body size more effectively than speech. Here, we investigated acoustic cues to strength and size in roars compared to screams and speech sentences produced in both aggressive and distress contexts. Using playback experiments, we then tested whether listeners can reliably infer a vocalizer's actual strength and height from roars, screams, and valenced speech equivalents, and which acoustic features predicted listeners' judgments. While there were no consistent acoustic cues to strength in any vocal stimuli, listeners accurately judged inter-individual differences in strength, and did so most effectively from aggressive voice stimuli (roars and aggressive speech). In addition, listeners more accurately judged strength from roars than from aggressive speech. In contrast, listeners' judgments of height were most accurate for speech stimuli. These results support the prediction that vocalizers maximize impressions of physical strength in aggressive compared to distress contexts, and that inter-individual variation in strength may only be honestly communicated in vocalizations that function to communicate threat, particularly roars. Thus, in continuity with nonhuman mammals, the acoustic structure of human aggressive roars may have been selected to communicate, and to some extent exaggerate, functional cues to physical formidability.

What Modern Sports Competitions Can Tell Us About Human Nature

To fully understand human behavior, it seems inevitable to approach it from an evolutionary perspective. However, much of human behavior has been overwritten by culture and society, thus allowing little insight into how it might have evolved amid natural and sexual selection. Here, I argue that sports competitions, although a cultural phenomenon in themselves, strip away many of the cultural layers and reveal more primary, rudimentary aspects of human behavior. Fortunately, because they are ubiquitous, meticulously recorded, and often quantified in great detail, sports competitions provide a plethora of usable data. In this article I provide an evolutionary account of the cross-cultural existence and popularity of sports by reviewing evidence of four functional hypotheses that regard the omnipresence of sports as a by-product of fitness-related adaptations (skill acquisition and development, status seeking, courtship display, and coalition formation). Then I outline how the growing body of sports data and documentation can be exploited for increasing our understanding of human nature (e.g., on conflict and cooperation, lateral preferences, territoriality, and nonverbal communication). The article concludes by giving guidelines for future cross-disciplinary research to advance the understanding of how evolution has shaped human behavior.

Multimodal stress detection: Testing for covariation in vocal, hormonal and physiological responses to Trier Social Stress Test

Examining the effects of acute stress across multiple modalities (behavioral, physiological, and endocrinological) can increase our understanding of the interplay among stress systems, and may improve the efficacy of stress detection. A multimodal approach also allows for verification of the biological stress response, which can vary between individuals due to myriad internal and external factors, thus allowing for reliable interpretation of behavioral markers of stress. Here, controlling for variables known to affect the magnitude of the stress response, we utilized the Trier Social Stress Test (TSST) to elicit an acute stress response in 80 healthy adult men and women. The TSST involves an interview-style oral presentation and critical social evaluation, and is highly effective in inducing psychosocial stress. Participants completed the study in individual 2 h sessions, during which we collected voice, polygraph and salivary hormone measures in baseline, stress, and relaxation phases. Our results show sizeable systematic increases in voice pitch (mean, minimum and variation in fundamental frequency, F0), hormone levels (cortisol) and decreases in skin temperature and hand movement during psychosocial stress, with striking similarities between men and women. However, cortisol and skin temperature only weakly predicted changes in voice pitch during stress, in either women or men, respectively. Thus, while our results provide compelling evidence that psychosocial stress manifests itself behaviorally by increasing voice pitch and its variability alongside simultaneous activation of physiological and endocrinological stress systems, our results also highlight a relatively weak degree of intra-individual 'response coherence' across these stress systems, with dissociations among different stress measures related most strongly to sex.

Trash-Talking and Trolling

Among the extra-physical aspects of team sports, the ways in which players talk to each other are among the more colorful but understudied dimensions of competition. To contribute an empirical basis for examining the nature of "trash talk," we present the results of a study of 291 varsity athletes who compete in the top division among US universities. Based on a preliminary review of trash-talk topics among student-athletes, we asked participants to indicate the frequency with which they have communicated or heard others talk about opposing players' athleticism, playing ability, physical appearance, boyfriends, girlfriends, sexual behavior, parents, and home institution during competitions. Our three main findings are: (1) Trash-talking is most commonly about the proximately important topic of playing ability while ultimately relevant topics such as physical appearance also appear to be common; (2) Men appear to trash-talk significantly more than women, and consistently across topics; and (3) contact sports such as football, hockey, lacrosse, and wrestling are associated with trash talk significantly more than other sports. We also examined whether the anonymity provided by face-masked helmets in "combat sports" was associated with more trash talk than contact sports played without a helmet (e.g., wrestling) and found no consistent association with face masks. Our findings highlight the ways in which competitors in physical sporting contests attempt to use language-often in ways that focus on players' kin or reproductive interests-in pursuit of victory while establishing a baseline for future research into trash-talking.