The influence of students' behavioral definitions on subsequent teacher behaviors was investigated with a simulation which allowed teachers using a microcomputer and video display terminal to verbally interact with four simulated students programmed to vary on knowledge and initiative. These "students," in turn, responded to teacher questions and asked questions on their own. The stability of teacher behavior within a simulation, differences among teachers in their use of positive affect as a consequence, and global changes in teacher patterns within the simulation were specifically addressed. Subjects were 40 teachers enrolled in the University of Virginia School of Education, who were divided into four subgroups representing factorial combinations of training area and experience. During two 20-minute sessions, teachers individually conducted a spelling lesson by instructing, questioning, calling on students, or using other appropriate behavior. Results indicated individual teacher patterns were quite consistent. High-knowledge students received more positive affect, overall, as a consequence than their low-knowledge classmates, with the quiet high-knowledge students rewarded relatively most often. As a group, teachers demonstrated changes in behavior over time, indicating a move toward relatively greater emphasis upon instruction and teacher-determination of targeted students. Results of the study indicate that the simulation influenced teacher behavior in a logical and predictable manner. Five references and two tables are included. (LMM)