title: Cross-cultural effects on the assumed light source direction: evidence from English and Hebrew readers.
abstract: When judging the 3D shape of a shaded image, observers generally assume that the light source is placed above and to the left. This leftward bias has been attributed to experiential factors shaped by the observers' handedness or hemispheric dominance. Others have found that experiential factors can rapidly modify the direction of the assumed light source, suggesting a role for learning in shaping perceptual expectations. In the current study, instead, we assessed the contribution of cultural factors affecting the way visual scenes are customarily inspected, in determining the assumed light source direction. Left- and right-handed first language English and Hebrew participants, who read and write from left to right and from right to left, respectively, judged the relative depth of the central hexagon surrounded by six shaded hexagons. We found a left bias in first language English participants, but a significantly smaller one in Hebrew participants. In neither group was the light direction affected by participants' handedness. We conclude that the bias in the assumed light source direction is affected by cultural factors, likely related to the habitual scanning direction employed by participants when reading and writing their first language script.
authors.affiliation: School of Psychology, Bangor University, Bangor, UK.
authors.forename: Bridget
authors.initials: B
authors.lastname: Andrews
authors.forename: Daniela
authors.initials: D
authors.lastname: Aisenberg
authors.forename: Giovanni
authors.initials: G
authors.lastname: d'Avossa
authors.forename: Ayelet
authors.initials: A
authors.lastname: Sapir
mesh_terms: D000328:Adult; D003431:Cross-Cultural Comparison; D007839:Functional Laterality / Q000502:physiology*; D006801:Humans; D007802:Language; D008027:Light; D011578:Psycholinguistics; D011932:Reading; D014796:Visual Perception / Q000502:physiology*; D055815:Young Adult
keywords: light source assumptions; scanning direction; shape from shading