Effects of culture and the urban environment on the development of the Ebbinghaus illusion

The development of visual context effects in the Ebbinghaus illusion in the United Kingdom and in remote and urban Namibians (UN) was investigated (N = 336). Remote traditional Himba children showed no illusion up until 9–10 years, whereas UK children showed a robust illusion from 7 to 8 years of age. Greater illusion in UK than in traditional Himba children was stable from 9 to 10 years to adulthood. A lesser illusion was seen in remote traditional Himba children than in UN children growing up in the nearest town to the traditional Himba villages across age groups. We conclude that cross-cultural differences in perceptual biases to process visual context emerge in early childhood and are influenced by the urban environment.