Ze vergelijken "peer group work" en "teacher-guided groups".
Ten aanzien van de rol van de docent:
"The comparatively formal tone of teacher-guided groups and students' tendency to wait until being addressed directly by the teacher before speaking up may have prevented some idea generation and intellectual risk taking."
"It was no doubt valuable for students to participate in reasoning with an adult who crystalized key issues to move their thinking along. However, attainment of high levels of reasoning through an inefficient, exploratory process in a greater number of turns required intellectual perseverance within peer groups, which is a valuable scientific habit of mind. The more peers talked about conceptual issues, the higher the reasoning levels they achieved. For groups that did not have such persistence, teacher invention was especially critical to attain higher levels of reasoning."