A hypothesis that the difficulties which subjects encounter whilst engaged in a traditional discrimination learning task may be seen as influenced by symmetry of individual stimuli as well as of arrangements of stimuli was examined. The data obtained as well as published data are interpreted as suggesting that the nature of symmetry of an individual stimulus determines the probability that it will be correctly recalled, such probabilities decreasing as one moves from stimuli symmetrical about both the principal axes, to stimuli symmetrical about the vertical axis, to stimuli symmetrical about the horizontal axis, to skew symmetrical stimuli and, finally, to random stimuli. The same data are also taken to suggest that the confusion between two stimuli in an array changes within the nature of symmetry of the array in a similar manner; the doubly symmetrical array being most and the asymmetrical array least confusing. © 1974.
Deregowski, J. B., & Ellis, D. (1974). Symmetry and discrimination learning. Acta Psychologica, 38(2), 81–91. https://doi.org/10.1016/0001-6918(74)90019-5