EBBINGHAUS ILLUSION - CONTEXT, CONTOUR, AND AGE INFLUENCE THE JUDGED SIZE OF A CIRCLE AMIDST CIRCLES

Ss (groups of ages 6, 8, 10, 12, and 21 yrs, with 60 or more persons per group) made comparative size judgments between a single circle and a standard circle that was flanked by 4 context circles. The context circles varied in diameter, proximity to the standard circle, and amount of circumference displayed. (When circumferences are complete, the display is the usual Ebbinghaus configuration. A variant consisted of the Ebbinghaus display with the outer three-quarters of each context-circle circumference removed.) A contour-plus-context theory accounts for the data: Contours attract at every age level, and context (size of flanking circles relative to the standard circle) leads to contrast in judged size beyond age 6. Contour and context effects decreased with decreasing proximity between context circles and the standard circle. (15 ref) (PsycINFO Database Record (c) 2006 APA, all rights reserved). © 1979 American Psychological Association.