SEQUENTIAL EFFECTS IN CHOICE REACTION TIME

4 experiments, using undergraduates, examined sequential dependencies in choice RT as a function of number of alternatives, stimulus-response (S-R) compatibility, and the intertrial interval (ITI). A 5th experiment investigated guessing strategies. The 2-choice compatible RT data revealed speeded responses to stimuli following certain alternating and some repeating sequences of stimuli. Similar patterns were obtained in the guessing task of Exp. V. Negative recency occurred in both the 2- and 4-choice compatible tasks, and negative recency increased as ITI decreased. With less compatible S-R codes, repetitions facilitated RT in both 2- and 4-choice tasks only after 2 repetitions. With a highly incompatible 4-choice task, 1 repetition was sufficient to facilitate RT maximally. With incompatible codes, ITI had no effect. It is suggested that the sequential effects in choice RT reflect processing strategies which depend on the complexity of the S-R code. (PsycINFO Database Record (c) 2006 APA, all rights reserved). © 1969 American Psychological Association.