Postclassification category use: The effects of learning to use categories after learning to classify

The use of category knowledge can affect category representations, including classification knowledge, even if people learn to classify before learning to use the categories. In 5 experiments, subjects first learned to classify spy messages and then learned a category use that required simple problem solving (applying a formula to decode a message). The number relations that were important for the decoding were later used as an additional basis of classification. This effect of category use occurred even when the classification was not provided during use learning, if the category representation was incidentally available. This incidental activation of the category representation is common in real-world situations and can occur by additional processing (Experiment 2) or by extended classification learning (Experiments 3-5). The discussion focuses on the conditions necessary for obtaining this effect and the generality of the findings.