Social anxiety: how competition, sex, and dispersal affect our propensity to interact socially

Social interactions can be beneficial by allowing individuals to learn socially about their environment or collaborate to achieve outcomes that are otherwise unattainable. Social interactions can also be costly if individuals risk being exploited, attacked, or otherwise harmed as a result of the encounter. Individuals are expected to refrain from social interactions if the potential costs outweigh any benefits. We investigate when individuals are expected to reduce their social interactions, with a focus on sex, dispersal status and competition. Using a mathematical model, we find that competition and dispersal can reduce social interactions within a social group and, due to sexual selection, females are predicted to be less social than males. We then test whether sex and dispersal can shape social interactions in humans, using a standardized instrument to measure social anxiety and a novel behavioural game. Despite suggestions in our model and in the previous literature that women and immigrants are more likely to suffer from social anxiety, our empirical results did not support the theoretical expectations. We discuss potential reasons for this, including mechanisms counter to prior theories and methodological issues in the paradigm.