Major urban-rural differences in perception of a visual illusion

Culture shapes higher-level processes such as norms and reasoning styles. The extent to which culture affects more low-level, automatic mental processes remains largely unknown. Here we show stark cross-cultural differences in perception of the Coffer visual illusion, which contains two percepts: rectangles and circles. Our data reveal that 97% of US and UK participants see only rectangles or rectangles first, but 96% of Namibian Himba participants from traditional villages see only circles or circles first. How we see the world may be shaped by exposure to right-angled stimuli across an urban-rural gradient. These results have implications for research relying overwhelmingly on participants (human, machine, non-human animal) exposed to highly carpentered environments (urban environments for humans and machine training datasets, cages/aquaria for non-human animals).