The locus of knowledge effects in concept learning.

Three experiments investigated how knowledge influences concept formation and representation in a standard concept acquisition task. The primary comparison was among arbitrary concepts, which had meaningless features; meaningful concepts, which had meaningful features from different domains; and integrated concepts, which had meaningful features interconnected by common knowledge. Experiment 1 found that learning was superior for the integrated concepts but that there was little difference as a function of feature meaningfulness. Experiment 2 suggested that the integrated Ss were learning to form a knowledge-based schema as their concept representation because they did not distinguish the typicality of features that differed in frequency. Experiment 3 introduced a category whose features were from the same domain but were not otherwise related. This concept was as difficult to learn and use as the meaningful concepts were. These comparisons help specify the ways in which knowledge does and does not influence concept formation.