Abstract
Rhesus monkeys were trained to criterion on a 2-stimulus and a 5-stimulus pattern discrimination task. The probabilities of response to the various stimuli throughout learning are examined for individual Ss, and it is found that Ss exhibit consistency in the order and manner in which incorrect stimuli are eliminated. This suggests a simple mathematical description of the process, which is used to deepen the analysis of the data, permitting estimation of individual learning parameters and construction of more meaningful summaries of the group data.