Expectancy in choice reaction time: Anticipation of stimulus or response?

Abstract

24 undergraduates predicted the stimulus to be presented in a discrete 3-stimulus, 2-response RT experiment. Mean RTs were significantly faster only when the stimulus was correctly predicted. Mean RTs to an incorrectly predicted stimulus with the same response as the predicted stimulus did not differ from the RTs to a stimulus with a different response. Results are interpreted as indicating a stimulus expectancy effect in choice RT. Factors influencing relative contributions of stimulus and response components in choice RT are discussed. (17 ref.) (PsycINFO Database Record (c) 2006 APA, all rights reserved)