Previous work by Grannis and Jackson suggested that teachers, learners, feedback sources, instructional sequencing, material format, or other variables may exercise control over the learning environment. It was suggested that the behavioral structure of a classroom can be described in terms of a knowledge dimension, a social dimension, and an authority structure dimension, and that congruence between these dimensions creates a learning environment that is effective in eliciting achievement. The current research investigated the relationship between congruence and learner involvement in the task, and between congurence and achievement at two different levels of mental processing. One hundred fourteen ninth grade algebra students were taught a unit on probability with semi-programed materials. In two classrooms, the instruction was teacer-paced, and the teacher provided the authority structure of the classroom. In the other two classrooms, the work was individualized and self-paced. Though different distributions of control elicited varying amounts of on-task behavior, in all four learning environments the time spent on task was greater than 85 percent of the total. In terms of achievement, a combination of highly structured learning materials and a highly directive teaching style created the most effective environment both for lower and higher mental processes. (BW)