No Evidence for Shared Representations of Task Sets in Joint Task Switching

It has been suggested that actors corepresent a shared task context when they perform a task in a joint fashion. The present study examined the possibility of co-representation in joint task-switching, in which two actors shared two tasks that switched randomly across trials. Experiment 1 showed that when an actor performed the tasks individually, switch costs were obtained if the actors responded on the previous trial (go trial) but not if they did not respond (nogo trial). When two actors performed the tasks jointly, switch costs were obtained if the actor responded on the previous trial (actor repeat trials) but not if the co-actor responded (actor switch trials). In Experiment 2, a single actor performed both tasks of the joint condition to test whether the findings of Experiment 1 were due to the use of different response sets by the two actors. Switch costs were obtained for both repetitions and alternations of the response set, which rules out this possibility. Taken together, our findings provided little support for the idea that actors co-represent the task sets of their co-actors.