Learning Concepts from Definitions1

Most of the time in school we expect students to learn concepts from being told about them. However, very few studies have investigated the learning of concepts from definitions and explanations (Johnson & Stratton, 1966). In most of the research on so-called "concept learning" people are expected to induce concepts, such as two green borders, from cards displaying geometric figures. It is obvious that if the subject were told such a concept in advance he would sort out the cards perfectly. Hence, this research is of doubtful relevance to the concept teaching that goes on in schools (though see Carroll, 1964). The first purpose of the experiment described in this paper was simply to explore to what extent people can acquire concepts from exposure to definitions. A person has acquired a concept if he can identify instances of the concept and discriminate them from noninstances. The substantive language of the instruction and the test questions must be different. Otherwise, the person may be able to answer by "rote," that is, on the basis of surface orthographic or phonological information, without having comprehended the concept (see Anderson, 1972). Recent research indicates that procedures which induce semantic encoding strongly facilitate associative learning. Bobrow and Bower (1969) instructed subjects in one group to compose a sensible