PRIOR KNOWLEDGE AND SENSITIVITY TO FEATURE CORRELATIONS IN CATEGORY ACQUISITION

This study examined the effects of encoding instructions and subjects' prior knowledge on sensitivity to feature co-occurrence in the learni ng of two novel, ill-defined categories. Sixty-five subjects were allo cated to conditions in which they were either required to discriminate between the members of the categories (intentional instructions) or t o identify the features of each category instance (incidental instruct ions). Categories were presented with neutral labels or labels that cu ed the retrieval of prior knowledge. This additional information was p resented at the beginning or the end of the study phase. All instances were presented four times, followed by a test phase in which subjects classified old and new stimuli that varied in the extent to which the y preserved the correlations between feature values that were present in the study items. Analyses of test-phase categorisation indicated th at intentional encoding led to greater sensitivity to feature correlat ions than incidental encoding, and that provision of meaningful catego ry labels facilitated the encoding of correlations between features th at were seen to be consistent with prior knowledge. The implications o f these results for models of the interaction between similarity-based processes and prior knowledge are examined.