Gender composition mediates social facilitation effect in co-action condition.

Working with co-actors is a common work-organization mode. Whether the presence of opposite-sex co-actors (OCs) can induce social facilitation effect and how an actor's performance is influenced by the gender composition of co-actors remain unknown. The present study aims to examine the influence of the gender composition of co-actors on the intensity of the social facilitation effect. In Experiment 1, participants performed visual search tasks alone and in six co-action conditions with varying gender compositions. In Experiment 2, the participants performed modular arithmetic tasks in three conditions with electroencephalogram activity recorded and salivary cortisol measured: alone, with a same-sex co-actor (SC), and with an OC. Results indicated that the social facilitation effect was stronger in the presence of OCs than in the presence of only SCs. The intensities of social facilitation effect resulting from the varying gender composition of co-actors were obtained and compared. A participant's power of alpha band was lower, whereas power of beta band and normalised cortisol level were higher in the presence of an OC than in the presence of an SC. These findings provide insights into the influencing mechanisms of gender composition on the intensity of the social facilitation effect in the co-action condition.