Is an apple a fruit? Semantic relatedness as reflected by psychophysiological responsivity

In the present study, we investigated orienting response generalization across various types of semantically related stimuli. Four experiments, based on a modified version of the guilty knowledge technique, were designed to examine whether semantic relations based on abstract features are reflected by electrodermal responsivity. No generalization across coordinates was obtained, but a moderate degree of generalization was demonstrated between a word and its superordinate category (e.g., table-furniture) and between a word and its synonym. Complete generalization occurred from a verbal label of an object to its pictorial representation, and vice versa. These results are compatible with our proposal that partial identification of the test stimulus as relevant is a necessary condition for generalization in the guilty knowledge technique.