Evidence for a role of the responding agent in the joint compatibility effect.

The present study explored the role of the responding agent in a social context. To do so, we developed a compatibility task with socially relevant but task-irrelevant stimuli (own face, neutral face, and a friend's face). Participants were required to perform naming responses to coloured diamonds, while the faces were presented as irrelevant stimuli. We observed faster responses in face-name compatible than in incompatible conditions. When the task was distributed among two friends, we observed a compatibility effect in a joint go/no-go condition, in which both participants performed their go/no-go tasks together. In contrast, no compatibility effect was obtained in an individual go/no-go condition. Further, the experiment showed that this joint compatibility effect was based on the compatibility between the irrelevant face and the responding agent. This result demonstrates that features of the responding agent play a crucial role in the joint compatibility effect.