Chipman, S. F. (1977). Complexity and structure in visual patterns. Journal of Experimental Psychology: General, 106(3), 269-301.

A series of seven experiments investigated the determinants of judged pattern complexity, with emphasis on the identification and measurement of structural variables. In an exploratory study, it was found that the determinants of pattern complexity could be separated into quantitative variables (number of turns, amount of contour), which set an upper bound on complexity, and structural variables, which reduced perceived complexity from the upper bound value. Results indicated that a wide variety of structural features, those generated by similarity transformations and related opponent-color transformations, were perceptually effective in reducing perceived complexity. In addition, it seemed that partial or approximate structure was effective in reducing perceived complexity. Later experiments developed and extended these results. Partial or approximate symmetry was shown to have a systematic effect on perceived complexity. The relative effectiveness of 10 different structural relations within patterns was determined. Patterns of varying degrees of organization were shown to determine a family of power functions, and this result rendered the expression of effects of structure equivalent to multiplicative reductions in pattern quantity. In addition, the effects of partial structure were shown to follow approximately a square-area law. Finally, pair-comparison scaling was shown to yield results comparable to magnitude-estimation scaling, and multiple pattern structures were found to act as alternative, rather than additive, influences upon perceived complexity. Developmental and individual differences in complexity judgment are described. Results are discussed for their implications concerning patterns as stimuli in other experimental and naturalistic situations and are considered in relation to existing theories of pattern perception.