Meta-analysis of the red advantage in combat sports.

Research has previously documented that across a range of Olympic combat sports, wearing red is associated with a higher probability of winning contests, especially when bouts are close. Yet, the hypothesis for a red advantage has not been systematically examined across multiple tournaments. Here, we report 6,589 contest outcomes for boxing, taekwondo, and wrestling from seven Summer Olympic Games (1996-2020) and nine World Boxing Championships (2005-2021).

The prevalence of dyads in social life.

A salient objective feature of the social environment in which people find themselves is group size. Knowledge of group size is highly relevant to behavioural scientists given that humans spend considerable time in social settings and the number of others influences much of human behaviour. What size of group do people actually look for and encounter in everyday life? Here we report four survey studies and one experience-sampling study (total N = 4,398) which provide evidence for the predominance of the dyad in daily life.

Cooperation in Groups of Different Sizes: The Effects of Punishment and Reputation-Based Partner Choice.

Reputation and punishment are two distinct mechanisms that facilitate cooperation among strangers. However, empirical research on their effectiveness is mainly limited to relatively small groups and does not address how they enhance cooperation in relatively larger groups. We address this gap in the literature by testing hypotheses from competing perspectives about the extent to which reputation-based partner choice and punishment enhance cooperation in both small and large groups.