Physical determinants of the judged complexity of shapes.

Many psychological tasks vary in difficulty with the complexity of the stimulus objects involved. Complex visual objects are not only harder to reproduce from memory than simple ones (4, 6), but also harder to learn by name (4, 7) and to match (11). Complexity is an ill-defined variable, however. No two of the experiments referenced above employ exactly the same operations of physical measurement, and an essential communality between them is not easy to specify in objective terms. In the study reported here, ratings of the complexity of nonrepresentational shapes were obtained from a large number of Ss and related to measurable physical characteristics of the shapes. The results not only have interest in their own right, but also serve to indicate the physical variables most likely to be relevant to other tasks, like those initially mentioned, on which data are typically