Abstract: This study investigated the effects on category learning when the category members had the same features cross two dimensions or the match features cross two dimensions. The subjects who consisted of the first grade under-graduates in South China Normal University. were tested after learning the category materials with different feature structures. The unit amount and the error percentage during the learning phase and the reaction time and the error percentage during the testing phase were counted. Three experiments were included. In Experiment 1,the learning results were compared under three circumstances, the circumstance that the category members had the same features across dimensions, the circumstance that the category members had the matched features across two dimensions, and the circumstance that the category members had the unmatched features across two dimensions. In Experiment 2,the influence on the category learning were probed into when the category members had the same features across two separate dimensions. In Experiment 3,the influence on category learning were examined further when the members from the different categories had the same features across two dimensions. The results of the this research showed that: (1) When the category members had the same features across two dimensions, the category learning was advanced because the subjects tended to regard the two dimensions as one dimension.(2) The category learning was not advanced when the category members had the matched features across two dimensions or the same features across two separate dimensions.(3)There was negative effect in category learning when the members from the different categories had the same features across two dimensions. It was showed in this research that the features similarity would influence the determination of dimensions.

Key words: feature dimension, category learning, the same feature across dimensions, the matched feature across dimensions