Response programming in simple and choice reactions

Changing the nature of a motor response can produce a reliable change in choice reaction time, while the corresponding effect for simple reaction time is unreliable, and disappears with appropriate instructions and practice. The reliable effect for choice reactions was attributed to a component of the reaction time in which the response is programmed. This programming can be done in advance of the simple reaction-time interval thereby eliminating this component from the measured simple reaction time, although S may not necessarily take advantage of this possibility. According to this analysis, the Henry and Rogers "memory drum theory(") applies to choice reactions but not necessarily to the simple reactions which have been the primary basis for previous demonstrations.