Isomorphic categories

Learning and transfer were investigated for a categorical structure that could be mapped without loss of information from 1 sensory modality to another. The category space was composed of 3 nonoverlapping, linearly separable categories whose members were structured, temporal events. Each stimulus was composed of a sequence of on-off events that varied in duration and number of subevents (complexity). Categories were learned visually, haptically, or auditorily and transferred to the same or another modality. Despite the isomorphism across modalities, significant differences appeared in both learning and transfer. The visual modality showed an early learning advantage, with information on the transfer test preserved best when encoded visually during learning, worst when encoded haptically, with auditory encoding intermediate. False recognition rates were elevated when categories were learned haptically and transferred to another modality. In general, classification accuracy was highest for the category prototype, with false recognition of the category prototype higher in the cross-modality conditions. The results are discussed in terms of current theories in modality transfer including the difficulties inherent when calculation of similarity must be considered in a cross-modal situation.