Focusing on the achievement and motivational effects of analogies of varying enrichment levels when used with abstract, unfamiliar, and difficult content, this study examined their effects on instruction at the recall and application levels using content consisting of both concepts and principles. The subjects were 123 eighth-grade science students who were assigned to one of three treatment groups for each of six topics: (1) no analogy, (2) simple analogy, and (3) enriched analogy. An instructional booklet and a posttest booklet were distributed to each student, and both immediate and delayed posttests were administered. Analysis of variance revealed no significant main effects on any of the immediate posttests, i.e., recall, application, or total. In contrast, significance was approached or reached on 5 of the 12 delayed achievement test measures, 1 on the recall level and 4 on the application level. The results of this study suggest that, although analogies may not be very useful for either rote remember-level learning or application-level learning, they may often be very useful for creating linkages within memory that would have an important influence on meaningful understanding, long-term retention, far transfer, problem solving, and the skill of analogical reasoning. A 31-item reference list is provided. (RP)