Visual effects in picture and word categorization

Two experiments are reported in which participants categorized stimuli as b elonging or not belonging to the category of fruits. Blocks of pictures and words were used, with items referring to exemplars having either high or l ow intercategory visual similarity and/or semantic relatedness. For both pi ctures and words, response time was longer in the semantically related cond itions than in the unrelated condition. Furthermore, there was a strong eff ect of visual similarity for pictures but not for words when semantic relat edness was held constant: Participants took longer to classify pictures of fruits when these were mixed with visually similar vegetables than when the y were mixed with visually dissimilar vegetables. Reducing the stimulus vis ibility by adding a dot pattern had an additive effect for words but an int eractive effect for pictures. The results are explained in terms of a uniqu e locus for category decisions about pictures and words.