This report presents data obtained from an experiment in student teaching behaviors designed to suggest an explanation for the previously detected relationship between cooperating teacher behavior and student teacher utilization of skills acquired during microteaching training. In order to determine if one or the other explains more effectively the actual use of the learned target skill, two hypotheses were tested: (1) cooperating teachers utilization of the target skill would serve as a model of performance for the student teacher; and (2) the ecological system of the classroom acts as a supporter and promoter of the target skill. Thirty-two randomly selected first-year graduate students in an elementary education credentials program underwent microteaching training, one-half in situations where the cooperating teacher made high use of the target skill (asking probing questions) and one-half in situations where low use of the skill was made. After the microteaching phase, each group was divided in half and recombined to form two new groups with opposing experiences. The two new groups then underwent a one-week teaching experience, one in classroom settings accustomed to use of the target skill, the other in classrooms where the skill was little used. Observation and analysis revealed that, while members of both groups who had undergone microteaching in the target skill high usage classes initially made use of the skill, continuation of the usage was maximum in those classrooms where the students were accustomed to previous teacher utilization of the skill and could respond appropriately. Thus it would seem that the second hypothesis is a more effective explanation for target skill usage. (MB)