Capuchin monkeys like change:
The implications of this simple experiment shed some light on consumer behavior, [Dan Ariely, the James B. Duke Professor of psychology and behavioral economics at Duke University] said. Earlier work on variety-seeking has found that people eat 43 percent more M&M candies when there are 10 colors in the bowl instead of just seven. "People choose variety for variety's sake," Ariely said. "They often choose things they don't even like as well just for the variety. We knew about this, so the interesting thing was to figure out how basic it is."