Human instrumental learning: a critical review of data and theory.

This article reviews experimental data from human instrumental learning tasks in which people acquire knowledge about the consequences of their actions. The main part of the paper examines the stimulus conditions which appear to control the acquisition of instrumental knowledge. These conditions include contiguity between the action and outcome, the degree of contingency between them, and also the extent to which the action is a good relative predictor of the outcome. Several accounts are examined of the mechanism by which instrumental knowledge might be acquired, including: (i) a variety of rule-based models, in which learning consists of the acquisition of knowledge about statistical relationships between contingent events; (ii) a relative contiguity model, in which learning involves the acquisition of knowledge about temporal relationships; and (iii) an associative model, in which learning involves the formation of mental associations which are updated by a learning rule. The review indicates that at present, the data seem most consistent with the associative learning model. However, there remain empirical phenomena which have resisted theoretical analysis. A variety of questions which future research might profitably explore are considered.