Many behavioral theorists have suggested that self-directed activity is central to the learning process (e.g., Dewey, Piaget, Wertheimer). Accordingly, it was predicted that such activity bears a significant positive relationship to the quantity, quality, and variety of responses in a reading lesson. Moreover, it was expected that selected academic, cognitive, and demographic variables are consistently related to level of self-directed activity. A naturalistic observation system was developed to test the hypotheses and was used to determine a weighted measure of self-directed activity for 157 fourth grade pupils. The pupils were taught a reading lesson using an open-group interaction model. Pupil responses during the lesson were recorded, transcribed, and rated for quantity, quality, and variety. The findings did not confirm the major hypothesis that group self-directed activity level affects the quantity, quality, or variety of responses in a group directed reading-thinking activity. It was concluded that group quality of response level does have a positive effect upon individual, nonverbal, self-directed activity. (Author/WR)