The topic of interest underlying the present study concerns cognitive and conceptual development in adulthood. Specifically, we examined the ways in which professional education affects occupational therapy students’ perceptions and descriptions of patients’ nonverbal behavior. Thirteen subjects viewed 3 videotapes of patients in treatment and then described the patients’ responses. They viewed the videotapes twice. at the beginning of student training and one and a half years later. Results indicated that at the second viewing, the subjects’ accounts became more differentiated, more complex, and less conclusive. Also on the second viewing, subjects were more likely to corroborate their inferences concerning patients’ emotional reactions with concrete observations, but did not describe patients in common theoretical categories. This result indicates that subjects find it difficult to discuss individual cases in relation to newly acquired theoretical knowledge. We conclude that, rather than increased instruction in theory, students need increased opportunity to analyze individual cases by means of theoretical knowledge.