Thematic apperception test (TAT) is a projective psychological test developed during the 1930s by Henry A. Murray and Christiana D. Morgan at Harvard University. Proponents of the technique assert that subjects' responses, in the narratives they make up about ambiguous pictures of people, reveal their underlying motives, concerns, and the way they see the social world. Historically, the test has been among the most widely researched, taught, and used of such techniques.