The effects of category use on learned categories

Frequently, people learn to classify instances of a concept and later learn additional information about the concept. What is the effect of this later learning on the original classification? In five experiments, this issue w as investigated with a common classification paradigm in which symptom sets were classified into disease categories. After learning to classify these sets, the subjects learned to use the category to decide what treatment sho uld be given for a symptom set. The symptoms that were important for the tr eatments were later classified by disease more accurately and were generate d earlier from the disease name. However, this effect occurred only if the category representation was activated during the learning of the treatments . Thus, later learning about a particular use of the concept can sometimes affect the original classification.