This study explores the effects of cooperative and mastery learning methods, alone and in combination, on first and second grade students' learning and retention of basic economic facts. A 2 X 2 (cooperative X mastery) factorial design compared the achievement of 120 students randomly assigned by grade level stratification to one of four treatment conditions: cooperative learning; mastering learning; cooperative-mastery learning; and a control treatment (no cooperative or mastery learning). All subjects were administered a written pretest, posttest, and delayed posttest on their understanding of economic concepts. In addition, a randomly selected subsample of 64 students was interviewed using an oral pretest, posttest, and delayed posttest. The study suggests that the cooperative-mastery learning method is in line with current early childhood practices and has the capacity for simultaneously boosting the conceptual development and language development of young children. This capacity is said to stem from the method's provision of: (a) specific, positive feedback; (b) a social context for sustained effort and involvement in a topic; (c) child-child communication exchanges; and (d) adult-child communication exchanges. (EH)