Some argue that category learning is mediated by two competing systems of learning: one explicit, one implicit (Ashby et al., 1998). These systems are hypothesised to be responsible for learning rule-based and information-integration category structures respectively. However, little experimental work has directly investigated whether people are conscious of category knowledge learned by the implicit system. In this study, we directly compared explicit recognition memory for exemplars between these two category structures. Contrary to the predictions of the dual-systems approach, we found preliminary evidence of superior exemplar memory after information-integration category learning compared to rule-based learning. This result is consistent with the hypothesis that participants learn information-integration category structures by using complex rules.