He proceeded to study under Kurt Lewin at the University of Iowa, where Festinger received his MA in 1940 and PhD in 1942 in the field of child behavior. By his own admission, he was not interested in social psychology when he arrived at Iowa, and did not take a single course in social psychology during his entire time there; instead, he was interested in Lewin's earlier work on tension systems, but Lewin's focus had shifted to social psychology by the time Festinger arrived at Iowa. However, Festinger continued to pursue his original interests, studying level of aspiration, working on statistics, developing a quantitative model of decision making, and even publishing a laboratory study on rats. Explaining his lack of interest in social psychology at the time, Festinger stated, "The looser methodology of the social psychology studies, and the vagueness of relation of the data to Lewinian concepts and theories, all seemed unappealing to me in my youthful penchant for rigor." Festinger considered himself to be a freethinker and an atheist.