To prepare or not to prepare? When preparation of a response in Task 2 induces extra performance costs in Task 1.

In dual tasking, the no-go backward crosstalk effect (BCE) means that processing of Task 1 takes longer when Task 2 does not require a response (no-go trial) than when it requires a response (go trial). Thus, contrary to the usual observation, giving two successive responses counterintuitively reduces instead of increases performance costs for Task 1. Results from recent studies are in line with the notion that the no-go BCE reflects response inhibition, which is required to overcome an already prepared go response in Task 2, but which also spills over to motor execution in Task 1. No direct test of this hypothesis, however, has been carried out so far, and hence the present study was designed to fill this gap. The result of this study with n = 48 participants revealed that a no-go Task 2 impeded Task 1 performance when preparation of the Task 2 response was encouraged, but facilitated Task 1 performance when preparation of the Task 2 response was not encouraged.