Mental comparison and the symbolic distance effect

Abstract

The time required to compare two symbols varies inversely with the distance between their referents on the judged dimension. Evidence for this phenomenon, here called the symbolic distance effect, is reviewed, and the paper describes a new experiment designed to clarify the nature of the effective "distance" by disentangling ordinal and interval distances between the referents of compared symbols. The data show that doubling the size difference between two circles speeds comparison of their names, even when ordinal distance between the circles is held constant. Several explanations of the mental processes involved in such memory comparisons are then critically evaluated, and a "scan plus comparison" model is tentatively adopted.