1 a) Outline one cross-cultural study into the development of perceptual abilities. (8 marks)
b) Outline the nature- nurture debate in relation to explanations of perceptual development (16 marks)
a) Segall et al (1996) investigated whether the Miller-Lyer illusion has a cross-cultural effect. They showed the Miller-Lyer illusion to a group of South Africans and a group of rural Zulus, and asked them which line was the longest. Most of the urban South Africans identified the line with the inwardly pointing arrows as being longer than the line with the outwardly pointing arrows, even though the lines were actually the same length. Segall et al believed this was because they were used to an environment dominated by straight lines (e.g. in their buildings) and interpreted the diagram in 3D. In other words, they saw one line as a corner receding away from them, and the other as a corner projecting towards them. The brain interprets the line reading away as being further away, so interprets it as being larger than the image it forms on the retina.
The Zulus were less susceptible to the Miller-Lyer illusion than the urban South Africans- a large proportion of them identified the lines as being the same length. Segall et al believed this was because they were less familiar with an environment made heavily from straight lines (e.g. their huts was circular) so didn’t apply size constancy in the same way as the urban South…