Latency and Relative Frequency of Response in Psychophysical Discrimination

The relation between response latency and probability is discussed with particular reference to differences between mean times for correct and incorrect responses in difficult two‐choice discriminations. The predictions of some finite Markov chain models for this situation are considered, and possible modifications of these simple systems which may bring about features of observed data are discussed. Some results, in the form of curves of the latency—probability relation, are presented from earlier work and new discrimination experiments. These data are discussed in relation to theoretical interpretations based on a particular stochastic model which describes psychophysical discrimination in terms of the accumulation of units contributing to the overt response.