Theory-Based Reasoning in Clinical Psychologists

Progress in science is marked by the formation of theories that explain a body of observations. Contrary to this guiding philosophy, clinical psychologists have prescribed to an atheoretical system of diagnostic reasoning since 1980. We report two studies demonstrating that clinicians have not internalized atheoretical reasoning despite the system’s widespread acceptance. The results show that clinicians’ own theories about disorders significantly affect their diagnoses of hypothetical patients and memory for symptoms. Clinicians are cognitively driven to form and apply theories to observations despite decades of deliberate training, practice, and pressure to reason