Incidental concept learning, feature frequency, and correlated properties.

Four experiments examined sensitivity to feature frequencies and feature correlations as a function of intentional and incidental concept learning. Feature frequencies were encoded equally well across variations in learning strategies, and although classification decisions in both intentional and incidental conditions preserved correlated features, this sensitivity was achieved through different processes. With intentional learning, sensitivity to correlations resulted from explicit rules, whereas incidental encoding preserved correlations through a similarity-based analogical process. In incidental tasks that promoted exemplar storage, classification decisions were mediated by similarity to retrieved examples, and correlated features were indirectly preserved in this process. The results are discussed in terms of the diversity of encoding processes and representations that can occur with incidental category learning.