Foreperiod duration and the time course of preparation.

There is a clear conflict in the literature between studies which report a reduction and those which report a delay of reaction time to a signal (S2), which is just preceded by a non-informative signal (S1). The hypothesis is tested that these diverging results are due to the size of the foreperiod (FP) between a warning signal (W) and S1. In the first experiment S1 and S2 were both visual, while S1 was auditory and S2 was visual in the second experiment.