Verbal interference with perceptual classification: The effect of semantic structure

Abstract

In a task of the same form as the standard Stroop test, the relevant attribute was ellipse size and the required responses were the numbers 1 through 6 assigned to each of the ellipses in order of increasing size. The irrelevant attribute consisted of either alphabet letters or the numerical symbols 1 through 6 displayed in the center of each ellipse. The numerals produced more interference with the classification of the relevant attribute than the alphabet letters, supporting Klein's (1964) results. In addition, the interference due to the irrelevant numerical symbols increased as the distance between the values of the relevant and irrelevant attributes was decreased. Since "distance" is a structural property of the number system, this indicated that the competing response tendencies aroused by the irrelevant numericals involved the semantic structure for numbers. The same results were obtained when numerical quantity, rather than ellipse size, was the relevant attribute. © 1973 Psychonomic Society, Inc.