[Psychological complexity of the figures and properties of retention in visual short-term memory]

We investigated how the physical variables of complex figures had effects on psychological complexity and recognition of complex figures. Complexity was objectively defined by the amount of convex parts and Perimeter/square root of Area (P/square root of A), which varied with both the number of convex parts and the length of one convex part. In complexity judgments the results showed that the judged complexity was not well predicted by P/square root of A, and that the amount of convex parts rather than P/square root of A had much influence on the judged complexity. In a recognition experiment, the results showed that performance was dependent on both the number of convex parts and the length of one convex part when P/square root of A was held constant. When P/square root of A was low and constant, performance tended to deteriorate with increasing the amount of convex parts. But when P/square root of A was high and constant, performance peaked at a convex parts value of 8, and deteriorated at higher or lower values of convex parts. The results indicated that both the number of convex parts and the length of one convex part were effective in deteriorating retention in visual short-term memory, and that P/square root of A had indirect influence on performance.