How two share two tasks: evidence of a social psychological refractory period eVect

A strong assumption shared by major theoretical approaches to cognition posits that the human cognitive system has a limited capacity for information processing. Evidence supporting this claim comes from the dual-task paradigm in which one cognitive system has to process two tasks simultaneously. In this study, we examined whether bottleneck-like processing can also be elicited when a dual task is shared between two individuals. Under dual-task instructions giving priority to Task 1, we found evidence of a psychological refractory period eVect in dual-task and joint-task conditions. Under equal priority instructions, we replicated the Wnding of a psychological refractory period eVect in the dual-task, but not in the joint-task condition. These Wndings are in line with the assumption that a social psychological refractory period eVect can be induced across two individuals. We suggest that this eVect is due to taskspeciWc monitoring requirements. We discuss our Wndings with respect to both dual-task and joint action theories.