Variations in limited resources allocation towards friends and strangers in children and adolescents from seven economically and culturally diverse societies.

Humans are unique among primates in altruism and sharing limited recourses towards non-kin. Our study revealed the differences in proportions of individuals ready to share limited resources with virtual friend compared to virtual stranger in children and adolescents from seven ethnic groups, represented by four traditional rural African societies from Tanzania with different types of economy and three societies from Russia. The study was conducted between 2015 and 2020, and the data on 2253 individuals (1104 males and 1149 females) were obtained.

Factors Associated With Highest Symptoms of Anxiety During COVID-19: Cross-Cultural Study of 23 Countries.

The COVID-19 restrictions have impacted people's lifestyles in all spheres (social, psychological, political, economic, and others). This study explored which factors affected the level of anxiety during the time of the first wave of COVID-19 and subsequent quarantine in a substantial proportion of 23 countries, included in this study. The data was collected from May to August 2020 (5 June 2020).

Sex, population origin, age and average digit length as predictors of digit ratio in three large world populations.

Recently, a number of authors have claimed that sexual dimorphism in the second-to-fourth digit ratio (2D:4D) is simply dependent on digit length and is an artifact of allometry. The goal of our study is to verify the validity of these assumptions. The study sample comprised 7,582 individuals (3,802 men and 3,780 women) from three large world populations: Europeans (n = 3043), East Africans (n = 2844), and Central Asians (n = 1695).

Fertility and infant survival in men and women from rural regions of Northern Tanzania: gene candidates and sex-specific genetic associations.

Numerous factors, including family planning and modern contraception, disturb the potential associations between the number of children born and genetic factors in modern Western societies. The current progress of medicine and a relatively high level of well-being make it hard to test the association between children's survival rates and genetic factors in Western societies either. The goal of the current study was to reveal the possible associations between the number of children born and the number of children survived till the age of 5 y.