Response activation in overlapping tasks and the response-selection bottleneck.

The authors investigated the impact of response activation on dual-task performance by presenting a subliminal prime before the stimulus in Task 2 (S2) of a psychological refractory period (PRP) task. Congruence between prime and S2 modulated the reaction times in Task 2 at short stimulus onset asynchrony despite a PRP effect. This Task 2 congruence effect was paralleled by a Task 1 congruence effect and emerged exclusively under conditions of cross talk, whereas it did not occur under dual-task conditions preventing cross talk between tasks. This suggests that response activation operates during the PRP in dual tasks and affects the response times in Task 2 via cross talk between common processing elements at prebottleneck stages but not by directly affecting the postbottleneck stages.