N - 2 Repetition Cost Using a Truncated Trial Procedure in a Single-registration and Double-registration Design, 2018-2019

Backward inhibition has been posited to aid our ability to switch between tasks by counteracting the tendency to repeat a recently performed task. Evidence suggests that backward inhibition might be triggered during task-preparation, prior to performance, yet so far it has not been detected following trials involving task-preparation but no task-performance (Schuch & Koch, 2003 and Philipp, Jolicoeur, Falkenstein & Koch, 2007). However, those previous studies deployed a nogo method that might have prevented preparation-driven effects from being detected, due to the nogo signal wiping the effects of task processing (Lenartowicz, Yeung, & Cohen, 2011). To avoid the need for a nogo signal, we truncated trial n – 1 following task-preparation and used the n – 2 repetition cost (ABA versus CBA trial sequences) to measure the effect of returning to a previous task. In the cue-only abstract cues experiment we used abstract cues in an attempt to increase the size of any potential n – 2 repetition cost triggered by preparation on the preceding trial. In the double-registration cue-only experiment, responses were required to cues as well as to targets, to enable us to know that participants did some form of preparation on the truncated trials. In both experiments, the existence of an n – 2 repetition cost following truncated trials would constitute evidence that backward inhibition can be triggered task-preparation.