A Priori Probability Effects on Simple Reaction Time

Abstract

Three factors - immediate foreperiod (1.0 and 4.0 sec), previous foreperiod (1.0 and 4.0 sec) and a priori probability (0.8 and 0.2) - were employed in a variable foreperiod simple RT design. The possibility was examined that a priori probability functioned independently of the previous foreperiod effect, an hypothesis advanced as an explanation for the inverse relationship between simple RT and foreperiod length. This possibility was confirmed in the present investigation. In addition, the results supported the contention that it is what the subject knows, not what he does not know, which controls simple RT.