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Abstract Susceptibility to diseases and fear of infections might vary intra-individually, depending on life circumstances. The main aims of the current research were to examine whether perceived vulnerability to disease (PVD) is higher in expectant women and their partners as compared to their non-pregnant peers (Study 1), and to test whether a mother’s disease aversion during pregnancy relates to health of her newborn (Study 2). In Study 1 we collected cross-sectional data from 412 men and women varying in parenthood status. Pregnant female participants were more likely to exhibit higher levels of PVD as compared with childless peers, although mothers also reported relatively high PVD scores. PVD in men, generally lower than that of women, seemed to be rather independent of their parenthood status. In Study 2, a sample of 200 pregnant women completed the PVD scale during the second pregnancy trimester and a follow-up survey after their child was born. We found that PVD in pregnant women was not related to further health outcomes in their newborns. Birth weight, average Apgar score, and general health of a newborn were not associated with the pregnancy-period mother’s PVD score. However, the probability of giving birth to a child with 10 Apgar points was higher in younger mothers and tended to decrease with the increasing number of health issues before pregnancy. Overall, this research contributes to understanding of the health-oriented beliefs of expectant parents and parents of infants, but it also shows that the possible, PVD-related disease avoidance has a relatively little effect on basic markers of a newborn’s health.

Abstract Nonverbal acoustic parameters of the human voice provide cues to a vocaliser’s sex, age, and body size that are relevant in human social and sexual communication, and also increasingly so for computer-based voice recognition and synthesis technologies. While studies have shown some capacity in human listeners to gauge these biological traits from unseen speakers, it remains unknown whether speech complexity improves accuracy. Here, in over 200 vocalisers and 1500 listeners of both sexes, we test whether voice-based assessments of sex, age, height and weight vary from isolated vowels and words, to sequences of vowels and words, to full sentences or paragraphs. We show that while listeners judge sex and especially age more accurately as speech complexity increases, accuracy remains high across speech types, even for a single vowel sound. In contrast, the actual heights and weights of vocalisers explain comparatively less variance in listener’s assessments of body size, which do not vary systematically by speech type. Our results thus show that while more complex speech can improve listeners’ biological assessments, the gain is ecologically small, as listeners already show an impressive capacity to gauge speaker traits from extremely short bouts of standardised speech, likely owing to within-speaker stability in underlying nonverbal vocal parameters such as voice pitch. We discuss the methodological, technological, and social implications of these results.

Abstract Touch is the primary way people communicate intimacy in romantic relationships, and affectionate touch behaviors such as stroking, hugging and kissing are universally observed in partnerships all over the world. Here, we explored the association of love and affectionate touch behaviors in romantic partnerships in two studies comprising 7880 participants. In the first study, we used a cross-cultural survey conducted in 37 countries to test whether love was universally associated with affectionate touch behaviors. In the second study, using a more fine-tuned touch behavior scale, we tested whether the frequency of affectionate touch behaviors was related to love in romantic partnerships. As hypothesized, love was significantly and positively associated with affectionate touch behaviors in both studies and this result was replicated regardless of the inclusion of potentially relevant factors as controls. Altogether, our data strongly suggest that affectionate touch is a relatively stable characteristic of human romantic relationships that is robustly and reliably related to the degree of reported love between partners.

Measurement(s) COVID-19 Protocols, Restrictions • Health Behaviors • Personality and Behavioral Change, CTCAE • Emotion • Message Framing • Self-Determination Technology Type(s) Survey • Experiment Design Type Factor Type(s) COVID-19 Protocols, Restrictions • Health Behaviors • Loss-Gain Framing • Cognitive Reappraisal • Self-Determination Messaging Sample Characteristic - Organism Homo Sample Characteristic - Environment Daily Life Sample Characteristic - Location North America • South America • Africa • Australia • Europe • United Kingdom • Asia

Abstract Recent cross-cultural and neuro-hormonal investigations have suggested that love is a near universal phenomenon that has a biological background. Therefore, the remaining important question is not whether love exists worldwide but which cultural, social, or environmental factors influence experiences and expressions of love. In the present study, we explored whether countries’ modernization indexes are related to love experiences measured by three subscales (passion, intimacy, commitment) of the Triangular Love Scale. Analyzing data from 9474 individuals from 45 countries, we tested for relationships with country-level predictors, namely, modernization proxies (i.e., Human Development Index, World Modernization Index, Gender Inequality Index), collectivism, and average annual temperatures. We found that mean levels of love (especially intimacy) were higher in countries with higher modernization proxies, collectivism, and average annual temperatures. In conclusion, our results grant some support to the hypothesis that modernization processes might influence love experiences.

Abstract The digit ratio (2D:4D) is said to be a potential marker of exposure to prenatal sex steroids. Some studies suggest that the 2D:4D is also linked with the testosterone response to challenging situations due to organizational effect of prenatal hormonal milieu on adult endocrine functioning. However, up to date, there were only four studies (conducted on small samples) that examined the 2D:4D and the testosterone response to a challenging situation (i.e. physical exertion or aggressive context). Here, we examined the relationship between the 2D:4D and the testosterone change under an acute exercise among 97 men. We found that the digit ratios (the right 2D:4D, the left 2D:4D, and the right minus left 2D:4D) were neither predictors of pre-exercise testosterone, nor the change in testosterone level after a cycling task. Our results add a contradictory to previous studies evidence in a discussion on the links of the 2D:4D and the testosterone change.

The present global study attempts to verify the links between marital satisfaction and the number of children as well as its moderators in an international sample. Data for the study was obtained from our published dataset and included 7178 married individuals from 33 countries and territories. We found that the number of children was a significant negative predictor of marital satisfaction; also sex, education, and religiosity were interacting with the number of children and marital satisfaction, while there were no interactions with economic status and individual level of individualistic values. The main contribution of the present research is extending our knowledge on the relationship between marital satisfaction and the number of children in several, non-Western countries and territories.

Abstract It has been suggested that the preference for low WHRs evolved because low WHR provided a cue to female reproductive status and health, and therefore to her reproductive value. The present study aimed to test whether WHR might indeed be a reliable cue to female reproductive history (with lower WHRs indicating lower number of children). Previous studies showed such a relationship for modern and industrialized populations, but it has not been investigated in natural fertility, indigenous, more energy constrained populations facing greater trade-offs in energy allocation than do modern societies. Our sample comprised 925 women aged 13 to 95 years from seven non-industrial societies including tribes from Sub-Saharan Africa (Hadza, Datoga, and Isanzu), Western Siberia (Ob Ugric people: Khanty and Mansi), South America (Tsimane) and South Asia (Minahasans and Sangirese). We demonstrated a culturally stable, significant relationship between number of children and WHR among women, controlling for BMI and age. Based on these data, we suggest that WHR is a reliable cue to female reproductive history, and we discuss our results in the context of previous studies indicating usefulness of WHR as an indicator of health and fertility.

Studies have documented that traditional motor skills (i.e. motor habits) are part of the cultural way of life that characterises each society. Yet, it is still unclear to what extent motor skills are inherited through culture. Drawing on ethnology and motor behaviour, we addressed this issue through a detailed description of traditional pottery skills. Our goal was to quantify the influence of three kinds of constraints: the transcultural constraints of wheel-throwing, the cultural constraints induced via cultural transmission, and the potters' individual constraints. Five expert Nepalese potters were invited to produce three familiar pottery types, each in five specimens. A total of 31 different fashioning hand positions were identified. Most of them (14) were cross-cultural, ten positions were cultural, five positions were individual, and two positions were unique. Statistical tests indicated that the subset of positions used by the participants in this study were distinct from those of other cultural groups. Behaviours described in terms of fashioning duration, number of gestures, and hand position repertoires size highlighted both individual and cross-cultural traits. We also analysed the time series of the successive hand positions used throughout the fashioning of each vessel. Results showed, for each pottery type, strong reproducible sequences at the individual level and a clearly higher level of variability between potters. Overall, our findings confirm the existence of a cultural transmission in craft skills but also demonstrated that the skill is not fully determined by a cultural marking. We conclude that the influence of culture on craft skills should not be overstated, even if its role is significant given the fact that it reflects the socially transmitted part of the skill. Such research offers insights into archaeological problems in providing a representative view of how cultural constraints influence the motor skills implied in artefact manufacturing.

Attitudes towards aging are often negative, a phenomenon known as ageism. However, personal contact with older adults and intergenerational exchange in the context of close families may mitigate such negative tendencies. So far, these effects have been studied in Western and industrialized contexts. The present study extended this work to the Cook Islands archipelago, a group of islands in the South Pacific characterized by low levels of industrialization and relative isolation from foreign influences. We tested the hypothesis that attitudes toward aging in the Cook Islands would be more positive than in the world at large, and that, within the archipelago, attitudes towards aging would be more positive in smaller, less industrialized communities with closer family ties. Participants (n = 70), were recruited from three islands varying in community size and strength of the family ties among inhabitants. They rated their aging attitudes on four dimensions. Contrary to our hypotheses, attitudes in the Cook Islands did not differ from those reported in industrialized nations and did not vary significantly across islands, even after controlling for personal contact to older adults. Potential limitations and implications for future research are discussed.

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Literary fiction has been credited with considerable power to improve attitudes toward outgroups. It was even argued that it has been an important factor behind the global decline of violence against various minorities in the last centuries. Could it also help to reduce the human-inflicted suffering of animals? To test this, we studied the attitude toward animal welfare of n = 921 (experimental group) people of both sexes who read a short fragment of an unpublished novel with a motif of the physical abuse of an animal. The control group (n = 912) read a fragment of a similar length but not related to animals. After reading the text all subjects filled out an on-line questionnaire with seven items (camouflaged among many others items) measuring attitudes toward animal welfare. The questionnaire included also demographical questions, such as whether the subject keeps pets. We found that in comparison with the control group, the experimental group was significantly more concerned about animal welfare. This result indicates that literary fiction can influence attitudes toward other species. It is also worth noting that our study is characterized by a high level of ecological validity, i.e. a relatively high extent to which its results can be generalized (or extended) to real-world settings. Due to its specific design, which involved the cooperation of a bestselling author and his publisher, the study approximated the typical conditions in which people read fiction in a remarkably accurate way. Finally, our research has potential practical implications for promoting animal welfare.

The issue of cultural universality of waist-to-hip ratio (WHR) attractiveness in women is currently under debate. We tested men's preferences for female WHR in traditional society of Tsimane'(Native Amazonians) of the Bolivian rainforest (N = 66). Previous studies showed preferences for high WHR in traditional populations, but they did not control for the women's body mass.We used a method of stimulus creation that enabled us to overcome this problem. We found that WHR lower than the average WHR in the population is preferred independent of cultural conditions. Our participants preferred the silhouettes of low WHR, but high body mass index (BMI), which might suggest that previous results could be an artifact related to employed stimuli. We found also that preferences for female BMI are changeable and depend on environmental conditions and probably acculturation (distance from the city). Interestingly, the Tsimane' men did not associate female WHR with age, health, physical strength or fertility. This suggests that men do not have to be aware of the benefits associated with certain body proportions - an issue that requires further investigation.

Olfactory sensitivity varies between individuals. However, data regarding cross-cultural and inter-group differences are scarce. We compared the thresholds of odor detection of the traditional society of Tsimane' (native Amazonians of the Bolivian rainforest; n = 151) and people living in Dresden (Germany; n = 286) using "Sniffin' Sticks" threshold subtest. Tsimane' detected n-butanol at significantly lower concentrations than the German subjects. The distribution of thresholds of the Tsimane' was very specific, with 25% of Tsimane' obtaining better results in the olfactory test than any member of the German group. These data suggest that differences in olfactory sensitivity seem to be especially salient between industrialized and non-industrialized populations inhabiting different environmental conditions. We hypothesize that the possible sources of such differences are: (i) the impact of pollution which impairs the olfactory abilities of people from industrialized countries; (ii) better training of olfaction because of the higher importance of smell in traditional populations; (iii) environmental pressures shaping olfactory abilities in these populations.

Evolutionary accounts of human traits are often based on proxies for genetic fitness (e.g., number of sex partners, facial attractiveness). Instead of using proxies, actual differences in reproductive success is a more direct measure of darwinian fitness. Certain voice acoustics such as fundamental frequency and measures of health such as handgrip strength correlate with proxies of fitness, yet there are few studies showing the relation of these traits to reproduction. Here, we explore whether the fundamental frequency of the voice and handgrip strength account for differences in actual reproduction among a population of natural fertility humans. Our results show that both fundamental frequency and handgrip strength predict several measures of reproductive success among a group of indigenous Namibian females, particularly amongst the elderly, with weight also predicting reproductive outcomes among males. These findings demonstrate that both hormonally regulated and phenotypic quality markers can be used as measures of darwinian fitness among humans living under conditions that resemble the evolutionary environment of Homo sapiens. We also argue that these findings provide support for the Grandmother Hypothesis.