Analogy with knowledgeable learners: When analogy confers benefits and exacts costs

Though embedding analogy in a text can improve acquisition of concepts that are relatively unfamiliar to learners (Donnelly & McDaniel, 1993), it rema ins uncertain how analogy influences learning for learners with some backgr ound knowledge for the target material. We develop several theoretical poss ibilities and report an experiment to test these possibilities. Target conc epts familiar to college students were expressed either in literal form or through analogy, and the concepts were presented in a manner that either fa cilitated or discouraged contact with subjects' prior knowledge. As reveale d by multiple-choice testing, analogy facilitated learning when the targets were presented to discourage contact with prior knowledge. In contrast, an alogy decreased performance when the same targets were presented to facilit ate contact with prior knowledge. Possible interpretations of this unique f inding are discussed.