Abstract: The multiple systems theory in category learning was introduced in this paper. A set of experiments for the theory were conducted by the multiple systems theorists. The results showed that feedback practices, delayed feedback, the location of the response and discontinuous categories effected on information-integration category learning but not on rule-based category learning, whereas the simultaneous performance of a numerical Stroop task, a sequential memory scanning task and categories’ number impacted rule-based category learning but not information-integration category learning. Basing on the analysis of the prior researches, the authors proposed some issues about difficulties and differences between the category structures that had been not solved and some topics should be studied further

Key words: category learning, the multiple-systems theory, rule-based category learning, information-integration category learning