Apparent horizontal and vertical extents of patterns with and without a surround.
Following earlier informal observations, the first of two experiments confirmed that, whereas the vertical and horizontal extents of a printed passage are more or less veridically perceived when the passage is surrounded by margins as is usual on a page, they appear reduced when the margins are removed by cropping them close to the edges of the passage. In Exp. 2 with a horizontal-line grating a similar reduction occurred vertically but not horizontally, suggesting that the effect occurs for patterned regions but less or not at all for unpatterned, i.e., uniform, regions. The possible relationship between this effect and the Delboeuf illusion of size is discussed.
Day
R H
RH
School of Psychology, La Trobe University, Bundoora, Victoria, Australia.
Degoldi
B R
BR
D005260:Female; D006801:Humans; D008297:Male; D009903:Optical Illusions; D014716:Vertical Dimension; D014796:Visual Perception