Individual differences in social interaction contexts: Examining the role of personality traits in the degree of self-other integration

There is increasing evidence in the joint action literature that the degree of self-other integration is sensitive to situational factors that affect the social interaction context. Until now, however, no study has addressed the potential role of dispositional factors such as personality traits in observed interindividual variations. The current study aims to address this gap. Using the joint Simon effect (JSE) as a measure of the degree of self-other integration, our results highlight that the magnitude of the JSE is consistently higher among participants with a high level of Extraversion and Agreeableness compared to those with a low level. This seems to indicate that extravert and agreeable people exhibit increased self-other integration, i.e., a greater propensity to integrate others' action representations. These results are the first experimental evidence that personality traits can mediate the degree of self-other integration in social interaction contexts. We discuss our findings, and suggest that considering individual differences would help to clarify inconsistent results reported in the joint action literature regarding the impact of certain situational factors on the degree of self-other integration.