Is the perception of odour pleasantness shared across cultures and ecological conditions? Evidence from Amazonia, East Africa, New Guinea, Malaysia and Poland.

What makes an odour pleasant or unpleasant? The inherent properties of the constituent chemical compounds, or the nose of the beholder, driven by idiosyncratic differences and culture-specific learning? Here, 582 individuals, including Tanzanian Hadza hunter-gatherers, Amazonian Tsimane' horticulturalists, Yali from the Papuan highlands and two industrialized populations (Poles, Malaysians), rated the pleasantness of 15 odour samples. We find considerable similarities in odour assessments across cultures, but our data do not fully support a claim regarding the universality of smell preferences. Despite cross-cultural similarities in olfactory assessments, probably driven by odour properties, we suggest that odour availability in ecological and cultural niches bears an undeniable effect on human odour preferences.

Validation of the Short Version (TLS-15) of the Triangular Love Scale (TLS-45) across 37 Languages.

Love is a phenomenon that occurs across the world and affects many aspects of human life, including the choice of, and process of bonding with, a romantic partner. Thus, developing a reliable and valid measure of love experiences is crucial. One of the most popular tools to quantify love is Sternberg's 45-item Triangular Love Scale (TLS-45), which measures three love components: intimacy, passion, and commitment. However, our literature review reveals that most studies (64%) use a broad variety of shortened versions of the TLS-45. Here, aiming to achieve scientific consensus and improve the reliability, comparability, and generalizability of results across studies, we developed a short version of the scale-the TLS-15-comprised of 15 items with 5-point, rather than 9-point, response scales. In Study 1 (N = 7,332), we re-analyzed secondary data from a large-scale multinational study that validated the original TLS-45 to establish whether the scale could be truncated. In Study 2 (N = 307), we provided evidence for the three-factor structure of the TLS-15 and its reliability. Study 3 (N = 413) confirmed convergent validity and test-retest stability of the TLS-15. Study 4 (N = 60,311) presented a large-scale validation across 37 linguistic versions of the TLS-15 on a cross-cultural sample spanning every continent of the globe. The overall results provide support for the reliability, validity, and cross-cultural invariance of the TLS-15, which can be used as a measure of love components-either separately or jointly as a three-factor measure.

Exploring Attitudes Toward "Sugar Relationships" Across 87 Countries: A Global Perspective on Exchanges of Resources for Sex and Companionship.

The current study investigates attitudes toward one form of sex for resources: the so-called sugar relationships, which often involve exchanges of resources for sex and/or companionship. The present study examined associations among attitudes toward sugar relationships and relevant variables (e.g., sex, sociosexuality, gender inequality, parasitic exposure) in 69,924 participants across 87 countries. Two self-report measures of Acceptance of Sugar Relationships (ASR) developed for younger companion providers (ASR-YWMS) and older resource providers (ASR-OMWS) were translated into 37 languages. We tested cross-sex and cross-linguistic construct equivalence, cross-cultural invariance in sex differences, and the importance of the hypothetical predictors of ASR. Both measures showed adequate psychometric properties in all languages (except the Persian version of ASR-YWMS). Results partially supported our hypotheses and were consistent with previous theoretical considerations and empirical evidence on human mating. For example, at the individual level, sociosexual orientation, traditional gender roles, and pathogen prevalence were significant predictors of both ASR-YWMS and ASR-OMWS. At the country level, gender inequality and parasite stress positively predicted the ASR-YWMS. However, being a woman negatively predicted the ASR-OMWS, but positively predicted the ASR-YWMS. At country-level, ingroup favoritism and parasite stress positively predicted the ASR-OMWS. Furthermore, significant cross-subregional differences were found in the openness to sugar relationships (both ASR-YWMS and ASR-OMWS scores) across subregions. Finally, significant differences were found between ASR-YWMS and ASR-OMWS when compared in each subregion. The ASR-YWMS was significantly higher than the ASR-OMWS in all subregions, except for Northern Africa and Western Asia.

Ownership-attributing intuitions are cross-culturally shared.

This study tested intuitions about ownership in children of Dani people, an indigenous Papuan society (N = 79, Mage = 7, 49.4% females). The results show that similar to studies with children from Western societies, children infer ownership from (1) control of permission, (2) ownership of the territory the object is located in, and (3) manmade versus natural origins of the object. By contrast, they did not (4) infer ownership from the first observed possession of an object. Additionally, Papuan children showed (5) an absolute first possession heuristic, whereby they assigned ownership to a person who achieved a goal, in contrast to a person who was first to pursue this goal but failed to be the first to claim it.

Typical diet and type of economy do not predict food-sharing behaviors in three Tanzanian societies.

Food sharing behavior is a widely observed phenomenon, and it draws attention of scholars interested in finding both proximate and ultimate explanations of such practices. In the current study, we focused on possible socio-economic and environmental food-sharing predictors: type of economy (i.e., immediate-return vs. delayed-return) and typical diet composition (i.e., proportion of proteins and carbohydrates in typical daily caloric intake). We investigated whether members of three societies from Tanzania (N = 177), namely hunter-gatherers (Hadza), pastoralists (Datoga), and agriculturalists (Iraqw) differ with regard to food-sharing patterns in the Dictator Game and reactions to violations of the food-sharing norms in the Ultimatum Game. We found that neither the type of economy nor the typical diet influenced our outcomes. The results indicated, however, that food sharing behavior was positively predicted by certain individual-level characteristics: people of higher strength and lower body fat shared more food, and women were more willing to share food than men.

Sex differences in human mate preferences vary across sex ratios.

A wide range of literature connects sex ratio and mating behaviours in non-human animals. However, research examining sex ratio and human mating is limited in scope. Prior work has examined the relationship between sex ratio and desire for short-term, uncommitted mating as well as outcomes such as marriage and divorce rates. Less empirical attention has been directed towards the relationship between sex ratio and mate preferences, despite the importance of mate preferences in the human mating literature. To address this gap, we examined sex ratio's relationship to the variation in preferences for attractiveness, resources, kindness, intelligence and health in a long-term mate across 45 countries (n = 14 487). We predicted that mate preferences would vary according to relative power of choice on the mating market, with increased power derived from having relatively few competitors and numerous potential mates. We found that each sex tended to report more demanding preferences for attractiveness and resources where the opposite sex was abundant, compared to where the opposite sex was scarce. This pattern dovetails with those found for mating strategies in humans and mate preferences across species, highlighting the importance of sex ratio for understanding variation in human mate preferences.

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

Fundamental frequency (fo), 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 fo to biological and social speaker traits and life outcomes, from reproductive to economic. Critically, researchers have used myriad speech stimuli to measure fo and infer its functional relevance, from individual vowels to longer bouts of spontaneous speech. Here, we acoustically analysed fo 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 fo measures from diverse speech stimuli, and second, to test the prediction that the vast inter-individual differences in habitual fo 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 fo can be explained between any two speech types. Beyond methodological implications, together with recent evidence that inter-individual differences in fo 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.

Are Beards Honest Signals of Male Dominance and Testosterone?

The male beard is one of the most visually salient and sexually dimorphic traits and a hypothesized potential marker of other traits, such as dominance, masculinity, social status, and self-confidence. However, as men can easily alter their facial hair, beards may provide unreliable information about the beard owner's characteristics. Here, we examined whether beards are honest signals of biological (testosterone levels) and psychological (self-reported dominance) traits. Young (M = 21.29, SD = 1.54) and healthy men (N = 97) participated in the study. Their beards were measured directly (using digital calipers) and by self-report. Participants provided saliva samples before and after acute exercise (to assess their testosterone and cortisol levels) and reported their dominance on a 5-item scale. The results showed that beard length (directly measured and self-reported) was not related to testosterone levels or dominance; thus, no evidence was found to support the hypothesis that beards are honest (or dishonest) signals of the beard owners' testosterone levels and dominance.

Human Stress Detection: Cortisol Levels in Stressed Speakers Predict Voice-Based Judgments of Stress.

Despite recent evidence of a positive relationship between cortisol levels and voice pitch in stressed speakers, the extent to which human listeners can reliably judge stress from the voice remains unknown. Here, we tested whether voice-based judgments of stress co-vary with the free cortisol levels and vocal parameters of speakers recorded in a real-life stressful situation (oral examination) and baseline (2 weeks prior). Hormone and acoustic analyses indicated elevated salivary cortisol levels and corresponding changes in voice pitch, vocal tract resonances (formants), and speed of speech during stress. In turn, listeners' stress ratings correlated significantly with speakers' cortisol levels. Higher pitched voices were consistently perceived as more stressed; however, the influence of formant frequencies, vocal perturbation and noise parameters on stress ratings varied across contexts, suggesting that listeners utilize different strategies when assessing calm versus stressed speech. These results indicate that nonverbal vocal cues can convey honest information about a speaker's underlying physiological level of stress that listeners can, to some extent, detect and utilize, while underscoring the necessity to control for individual differences in the biological stress response.

Sex Differences in Mate Preferences Across 45 Countries: A Large-Scale Replication.

Considerable research has examined human mate preferences across cultures, finding universal sex differences in preferences for attractiveness and resources as well as sources of systematic cultural variation. Two competing perspectives-an evolutionary psychological perspective and a biosocial role perspective-offer alternative explanations for these findings. However, the original data on which each perspective relies are decades old, and the literature is fraught with conflicting methods, analyses, results, and conclusions. Using a new 45-country sample (N = 14,399), we attempted to replicate classic studies and test both the evolutionary and biosocial role perspectives. Support for universal sex differences in preferences remains robust: Men, more than women, prefer attractive, young mates, and women, more than men, prefer older mates with financial prospects. Cross-culturally, both sexes have mates closer to their own ages as gender equality increases. Beyond age of partner, neither pathogen prevalence nor gender equality robustly predicted sex differences or preferences across countries.

Digit ratio and hand grip strength are associated with male competition outcomes: A study among traditional populations of the Yali and Hadza.

OBJECTIVES: Indirect measures of physiological features, such as digit ratio and hand grip strength (HGS), are associated with the outcome of male competition activities. However, most of the studies were conducted in developed and industrialized societies. We tested the hypothesis that both digit ratio and HGS are associated with performance in male-specific activities in two traditional preindustrial societies: Yali and Hadza. METHODS: To measure masculine behavioral traits, we determined warriorship status (Yali; n = 49) and assessed hunting skills (Yali n = 47 and Hadza n = 49). We also assessed the digit ratio and HGS of each male. We conducted our analyses using the Bayesian approach. RESULTS: Bayesian regression models indicated that greater hand grip strength is associated with better hunting outcomes among Hadza males. We did not find a similar link for the Yali. We found anecdotal evidence for the link between left hand digit ratio and the number of birds hunted by Hadza. We found no evidence for the link between digit ratio and performance in male-male competition. CONCLUSIONS: Our results suggest that male-male competition outcomes are determined by upper body strength, but only in the Hadza population. We also found limited support for the hypothesis that digit ratio is associated with hunting success among the Hadza. We found no support for the hypothesis concerning the digit ratio or HGS among the Yali. Our research provides partial support for the evolutionary hypotheses based on studies conducted in industrialized populations.

Human height preferences as a function of population size in the Cook Islands and Norway.

OBJECTIVES: Height preferences and mating patterns related to body size vary across cultures yet it remains unclear why such between-population differences exist. Here, we test a hypothesis that nonrandom assortative mating is negative (mating with nonsimilar partners) in small isolated populations, and positive (mating with similar partners) in larger populations. METHODS: We compared preferences for sexual dimorphism in stature (SDS, male height/female height) among men and women living in small isolated communities (as few as 60 inhabitants) vs larger urban areas (as many as 70 000 inhabitants). To increase generalizability, data were collected from heterogeneous populations in the South Pacific (Rarotonga vs Palmerston, Cook Islands) and Northern Europe (capital city of Tromsø vs villages in the Troms County of Norway). RESULTS: Norwegians preferred a significantly larger difference in height between partners (median SDS ratio of 1.14) than did Cook Islanders (median SDS ratios of 1-1.04). Indeed, while 30% of Cook Island men and women preferred a partner of the exact same height, this preference was observed among less than 3% of Norwegian men and 7% of Norwegian women. Critically, distributions in SDS preferences did not differ by sex or population size. Thus, rural and urban dwellers within both countries showed similar positive assortative preferences for height, wherein own height explained up to 62% of the variability in preferred partner height. CONCLUSIONS: Our results do not support negative assortative preferences in small-scale communities, and further indicate that the "male-taller norm," while weaker among Cook Islanders than Europeans, is observed to some extent in the South Pacific.

Similarities in Color Preferences Between Women and Men: The Case of Hadza, the Hunter-Gatherers From Tanzania.

Evidence for cross-cultural patterns of sexual differences in color preferences raised the question of whether these preferences are determined by universal principles. To address this question, we investigated most- and least-favorite color choices in a nonindustrialized community, the Hadza that has an egalitarian hunter-gatherer culture, fundamentally different from those previously investigated. We also compared color preference patterns in the Hadza with published data from Poland and Papua. Our results show that Hadza have very different color preferences than Polish and Papuan Yali respondents. Unlike many industrialized and nonindustrialized cultures, Hadza color preferences are practically the same for women and men. These observations question the idea of universal differences of color preferences between sexes and raise important questions about the determinants of color preferences.

Olfactory perception and blindness: a systematic review and meta-analysis.

Anecdotal reports suggest that blind people might develop supra-normal olfactory abilities. However, scientific evidence shows a mixed pattern of findings. Inconsistent observations are reported for both sensory-driven olfactory tasks (e.g., odor threshold) and higher-order olfactory functions (e.g., odor identification). To quantify the evidence systematically, we conducted a review and meta-analysis. Studies were included if they examined olfactory function (i.e., odor threshold, odor discrimination, free odor identification, or cued odor identification) in blind compared with a sighted control group. Articles were identified through computerized literature search. A total of 18 studies focused on olfactory threshold (n = 1227: 590 blind and 637 sighted individuals), 14 studies targeted discrimination (n = 940: 455 blind and 485 sighted), 14 studies measured cued identification (n = 968: 468 blind and 500 sighted), and 7 studies (n = 443: 224 blind and 219 sighted individuals) assessed free identification. Overall, there were no differences in effect sizes between the blind and sighted individuals after correcting the results for publication bias. We additionally conducted an exploratory analysis targeting the role played by three moderators of interests: participants' age, the proportion of women versus men in each of the studies included into meta-analysis and onset of blindness (early blind vs. late-blind). However, none of the moderators affected the observed results. To conclude, blindness seems not to affect cued/free odor identification, odor discrimination or odor thresholds.

Does the "incentive hope" hypothesis explain food-wasting behavior among humans? Yes and no.

In this commentary, we discuss how the "incentive hope" hypothesis explains differences in food-wasting behaviors among humans. We stress that the role of relevant ecological characteristics should be taken into consideration together with the incentive hope hypothesis: population mobility, animal domestication, and food-wasting visibility.

Development of an International Odor Identification Test for Children: The Universal Sniff Test.

OBJECTIVE: To assess olfactory function in children and to create and validate an odor identification test to diagnose olfactory dysfunction in children, which we called the Universal Sniff (U-Sniff) test. STUDY DESIGN: This is a multicenter study involving 19 countries. The U-Sniff test was developed in 3 phases including 1760 children age 5-7 years. Phase 1: identification of potentially recognizable odors; phase 2: selection of odorants for the odor identification test; and phase 3: evaluation of the test and acquisition of normative data. Test-retest reliability was evaluated in a subgroup of children (n = 27), and the test was validated using children with congenital anosmia (n = 14). RESULTS: Twelve odors were familiar to children and, therefore, included in the U-Sniff test. Children scored a mean ± SD of 9.88 ± 1.80 points out of 12. Normative data was obtained and reported for each country. The U-Sniff test demonstrated a high test-retest reliability (r27 = 0.83, P < .001) and enabled discrimination between normosmia and children with congenital anosmia with a sensitivity of 100% and specificity of 86%. CONCLUSIONS: The U-Sniff is a valid and reliable method of testing olfaction in children and can be used internationally.

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.