Chinese and Americans see opposite apparent motions in a Chinese character.

The perceived direction of apparent motion can be influenced by both "top-down" factors, such as expectation, and by "bottom-up" or stimulus-driven factors, such as grouping (Tse, P., Cavanagh, P. & Nakayama, K. (1998). The role of parsing in high-level motion processing. In T. Watanabe, High-level motion processing - computational, neurobiological and psychophysical perspectives. Cambridge, MA: MIT Press). Here we report the results of a single experiment that pitted top-down cues against bottom-up cues in an apparent motion sequence over the successive strokes of a Chinese character. Although each stroke was in fact presented all at once, subjects raised in China tended to see apparent motion over a single stroke in the direction it would have taken when drawn by hand, even though bottom-up cues drive a percept of apparent motion in the opposite direction for observers unfamiliar with the Chinese language. There is therefore a learned component to motion perception arising from top-down expectations capable of overriding bottom-up cues to motion.