Berlyne, the Canadian psychologist, famously conjectured that the aesthetic preference for visual patterns is an inverted-U function of their complexity. In my own research (Chipman, 1977), I developed and studied a large set of patterns, exploring what determined their judged complexity. These included patterns with several types of well defined structure, as well as randomly generated patterns. Several experiments explored the judged aesthetic quality of such patterns. Judged aesthetic quality was not any simple function of judged complexity. Not surprisingly, there are significant individual differences in aesthetic preference, including differences in preference for different types of visual structure.