| Abstract: | In a simple RT task the temporal organization of the preparatory processes during a given trial depends upon the time characteristics of the total experimental situation as well as upon the information gathered during one or more previous trials. The present experiment was run in order to determine whether or not these long and short term effects operate independently or interact. The effects of the preceding ISI durations on the simple RT for an ISI 1 (1.5 s) or an ISI 2 (3.0 s) are analysed in 3 experimental conditions differing in the maximum number of successive repetitions (2, 3 or 7) of trials with the same ISI. The results show that the distribution of the preparatory activity during a given trial depends firstly on the number of successive ISIs of the same duration preceding this trial, and secondly on the maximum number of repetitions. An explanation of the subjects' strategy based upon “cost of preparation” is proposed. |
