Two fifth grade classrooms representing the extremes of classrooms where students perceived high and low differential teacher treatment were studied to obtain a more in-depth picture of the nature of classrooms that are expected to have contrasting effects on students' expectations and self-evaluations, and to begin to explore a model of classroom factors contributing to the development of students' self-evaluations. In the low compared to the high student-perceived differential treatment classroom, more strategies were used which minimized the opportunity for comparisons between students' ability levels, e.g. divergent tasks, heterogeneous grouping, expressions of respect for individual differences in ease of learning, use of errors for learning rather than for peer comparison. The model--including the influence of other features within the classroom context which may overcome the effect of potentially detrimental factors--generally received support from this analysis. The importance of teachers' beliefs about the nature of ability and teachers' responsibility and effectiveness in implementing strategies for low achievers was also noted. (Author/EDC)