SEMANTIC DISTANCE AND SINGLE CUE USE IN CATEGORY SEARCH

Perceptual classification may be based either on the physical features of target and background items or on the semantic attributes of the p resented items. In this paper we used enumeration tasks to study the r ole of semantic features in a categorial classification task. This mea ns that subjects were asked to count the number of target words in a d isplay belonging to one semantic category among a number of background items of other categories. Our goal was to study the decision logic i n category search by manipulating target background conditions and the semantic distance between target and background classes. In the first experiment we found that the larger the semantic distance between tar gets and background words, the easier it was to find the targets. In t he second experiment we found a ''pop-out'' effect, in which subjects could use and benefit from a single distinctive semantic feature, ''pa rt-likeness'', in categorial classification. The results of the two ex periments imply that the categorization decision logic is basically th e same in physical and semantic perceptual classification.