This article tells of the author and her fellow teachers study on their students. Hammer explains that she and her colleagues took a two hour block at their junior high school and grouped students not by their ability but instead by their conceptual level. They found that there were three stages that were evident. First was stage A in which the students were concrete in their thinking patterns. It was also evident that at this stage the students were often physical in response to name calling by their peers. The students at stage A had low self-control and frustration levels. Hammers next group was stage B, which included students that were still at the concrete level but were more apt to work in small groups and handle choices. They found that seventy to eighty percent of seventh graders were at this stage. The final stage was stage C. Stage C is when many students begin to see themselves different from others. They are more apt to focus on themselves and not take into consideration others thoughts. At this stage hammer and her colleagues found it better to allow these students to work alone and be their own individual. This is a very good study and offers a developmentally appropriate way to separate students to gain maximum amount of student cooperation and also the best possible way to allow all children to learn in their own comfort zone.