Universal psychological laws; similarity, generalization, and classification; perception and representation of spatial transformations and of music; physics and mind; evolutionary psychology; multidimensional scaling and clustering.
In 1968 he joined the Stanford Faculty as a Professor of Psychology, and in 1989 he was named Ray Lyman Wilbur Professor of Social Science in the department. Many awards have recognized his contributions to cognitive science while at Stanford. Including the election to the National Academy of Sciences (1977), the National Medal of Science (1995), and the Rumelhart Prize in cognitive science (2006).