title: How a cognitive psychologist came to seek universal laws.
abstract: My early fascination with geometry and physics and, later, with perception and imagination inspired a hope that fundamental phenomena of psychology, like those of physics, might approximate universal laws. Ensuing research led me to the following candidates, formulated in terms of distances along shortest paths in abstract representational spaces: Generalization probability decreases exponentially and discrimination time reciprocally with distance. Time to determine the identity of shapes and, provisionally, relation between musical tones or keys increases linearly with distance. Invariance of the laws is achieved by constructing the representational spaces from psychological rather than physical data (using multidimensional scaling) and from considerations of geometry, group theory, and symmetry. Universality of the laws is suggested by their behavioral approximation in cognitively advanced species and by theoretical considerations of optimality. Just possibly, not only physics but also psychology can aspire to laws that ultimately reflect mathematical constraints, such as those of group theory and symmetry, and, so, are both universal and nonarbitrary.
authors.affiliation: Stanford University, Stanford, California, USA. rshepard@cox.net
authors.forename: Roger N
authors.initials: RN
authors.lastname: Shepard
mesh_terms: D003071:Cognition; D004192:Discrimination, Psychological; D004989:Ethics; D005793:Generalization, Psychological; D049673:History, 20th Century; D008433:Mathematics; D009146:Music; D011571:Psychoacoustics; D011584:Psychology / Q000266:history* / Q000379:methods*