[Decision strategy: effect of the proportion of total response time taken by choice reaction time].

Results from two series of studies on decision strategies suggested that subjects appeared to chose between two response modes. Subjects could use a decision strategy based either on anticipatory responses or on reaction responses. It appeared that certain characteristics specific to the task could be responsible for the discrepancy in the response mode. The aim of the present study was to ascertain whether the choice of a decision strategy could be dictated by the proportion of total response time taken up by the choice reaction time (TRC). For instance, if the TRC takes up a large proportion of the total time, reducing it in view of an anticipatory response could considerably reduce the total time. The advantage to be gained from an anticipatory response could thus be considered sufficient to warrant adoption of a decision strategy based on anticipation. On the contrary, when TRC takes up only a small portion of total time, a decision strategy based upon reactions is preferred since the cost related to an error in response would largely exceed the advantage related to anticipation. Results from the two series of experiments presented in this paper support the importance of this variable. More specifically, results revealed that the error that an individual allows himself to make depends upon the proportion of total time that is devoted to choice reaction time. An extension of the model presented by Proteau et al. is proposed in order to account for the present observations.