A study was conducted to investigate the peer concepts held by 16 second-grade, 17 fourth-grade, and 17 sixth-grade students. A paired comparisons sociometric procedure was used to obtain children's descriptions of their classmates in the areas of reading, mathematics, drawing, and an athletic skill (running). In addition, the procedure measured children's liking for classmates. Independent measures of each child's actual skills or characteristics were obtained from reading and mathematics achievement test scores, a measure of running speed, and teachers' ratings of drawing ability and popularity. Analyses indicated little differentiation of ability attributes by either the second or fourth graders. Sixth graders viewed drawing ability and mathematics skill as quite separate from other attributes, thus demonstrating partial differentiation of ability attributes. Accuracy of the children's choices relative to the objective measures showed increasing accuracy from second to fourth grade in judging reading skill, mathematics ability, and running speed. Decreased ability across grades was found in judging drawing ability. Moderate correspondence at younger levels, increasing through the sixth grade, was found between teachers' rankings of popularity and children's liking for peers. Findings thus indicated both the increasingly differentiated concepts of peers' abilities during the elementary school years and the limitations on concept differentiation resulting from changes in the salience of ability attributes over these years. (Author/RH)