SALIENCE OF CENTRAL FIGURE IN THE EBBINGHAUS ILLUSION - THE OREO COOKIE EFFECT

The Ebbinghaus illusion was used to study size estimation as influence d by salient features of the central figure. Two groups of fourth grad ers, 9 boys and 11 girls, and two groups of seventh graders, 9 boys an d 3 girls, judged the size of central figures (an Oreo cookie or a bla ck cardboard disc) with small and large black cardboard disc inducers. Responding showed the Oreo cookie was consistently perceived as large r than the cardboard disc when surrounded by the large inducing figure s. The results are discussed in terms of an interaction between the ge ometric properties and salience of the central figure with the surroun ds. This Oreo effect is nor predicted by a strict version of the token -value hypothesis and differs from explanations based on contrast and conceptual similarity.