Hemispheric Asymmetry in the Processing of Stroop Stimuli: A Balanced Design

Abstract

Based on results from earlier research, the Stroop test appears to be a means for gaining insight into the specialized functions of the cerebral hemispheres as related to sex differences. This study was designed to determine whether sex differences continue to be present in a balanced design. Sixty-two psychology students responded to color words printed in incongruent colors when presented by a slide projector. Four mean scores comprising 15 responses in each condition, grouped word, grouped color, random word, and random color were computed for each subject. One half of the subjects responded to the grouped condition first, while the other half responded to the random condition first. Two variables were considered, sex and the order of presentation of random and grouped modes. Analyses of covariance of color response times over the categories of sex and order of presentation with word scores as covariates were performed for all conditions. For all individuals, response latency was consistently shorter when reading the word than when reporting the color. As in earlier studies, the covariate (word scores) was significantly related to the color sores. Sex differences were not found; however a significant difference was found in the analysis of the random color responses. When means were adjusted for sex and the covariate, subjects having the experience of the grouped experiment first scored faster than those performing for the first time. It appears that in this balanced design, practice improves time on color responses for both sexes.