Sebanz et al. (Cognition 88:B11–B21, 2003) have shown that spatial correspondence effects are observed even when the two-choice reaction time task is distributed between two people, such that each person is assigned only one of two possible stimulus–response (S–R) pairings. The effect is similar to when one person is assigned and responds to both S–R pairings. These results have been taken to suggest that two people performing a complementary task co-represent each other’s response alternatives. In our experiment, we examined performance when paired participants responded to the same S–R alternative. We reasoned that co-representation would be of little advantage as the task alternatives would be the same for both participants. Correspondence effects were absent when paired participants responded to the same S–R alternative but emerged when they responded to different alternatives.
