The effects of R-S interval duration on serial choice reaction time: preparation time or response monitoring time?

Abstract

Most laboratory choice reaction experiments have been poor simulations of everyday tasks because they have only considered cases in which signals occur at a constant, regular rate. Experiment 1 therefore examined performance in a 2-. 4- and 8-choicc task in which the interval between each response and the next signal (RSI) varied from trial lo trial, taking values of 20. 50. 100, 150, or 200ms with equal probability in random order. In Experiment 2, RSIs were either constant at 20 ms or 200 ms throughout a run, or might adopt either value, equiprobably, at random. In Experiment 3, 20 ms and 200ms RSIs occurred in unpredictable order. In Condition I RSIs of 20 ms occurred in 75% of trials and RSIs of 200 ms in 25% of trials. In Condition 2 this bias was reversed. In Condition 3 the two possible RSIs occurred equally frequently. In all experiments RT fell as RSIs increased from 20 to 200 ms, irrespective of the number of choices, the repetition or alternation of responses and the predictability or equiproba...