Using college students, the hypothesis was tested that shape-constancy is a positive function of shape familiarity. Familiarity was defined as the number of times the shapes were presented during a familiarization period. The stimuli were 5 moderately complex shapes systematically constructed from randomly determined coordinates. The results showed that shape-constancy was a positive function of shape familiarity; that shape as a main effect was significant; and that the interaction of shape and frequency (in determining S's matching of a variable shape to the standard stimuli) was significant. Orientation during the familiarity period was not significant. Moreover, the number of orientation positions, within a given range, seemed to be unimportant. (PsycINFO Database Record (c) 2006 APA, all rights reserved)