Comparing Stroop-like and Simon Effects on Perceptual Features

Elisa Scerrati,Roberto Nicoletti,Carlo Umiltà,Luisa Lugli

doi:10.1038/s41598-017-18185-1

Abstract

Stroop-like and Simon tasks produce two sources of interference in human information processing. Despite being logically similar, it is still debated whether the conflicts ensuing from the two tasks are resolved by the same or different mechanisms. In the present study, we compare two accounts of the Stroop-like effect. According to the Perceptual Account, the Stroop-like effect is due to Stimulus-Stimulus congruence. According to the Decisional Account, the Stroop-like effect results from the same mechanisms that produce the Simon effect, that is, Stimulus-Response compatibility. In two experiments we produced Stroop-like and Simon effects by presenting left/right-located stimuli consisting of a colored square surrounded by a frame of the same color as the square or of a different color. Results showed that discriminating either the color of the square (Experiment 1) or that of the frame (Experiment 2) yielded additive Stroop-like and Simon effects. In addition, the patterns of temporal distributions of the two effects were different. These results support the Perceptual Account of the Stroop-like effect and the notion that the Stroop-like effect and the Simon effect occur at different processing stages and are attributable to different mechanisms.

Highlights

Imagine you are speaking at an important workshop over Skype and all of a sudden an alarm in your building sets off
Several authors posit that the Simon effect results from the automatic coding of stimulus position, which, in turn, automatically activates the spatially corresponding response, producing a competition, at the response selection stage, between the spatially corresponding response and the response required on the basis of task instructions[2,5]
Two participants, who made 16% of errors or more, were excluded, so that the final sample consisted of 14 participants

Summary

Introduction

Imagine you are speaking at an important workshop over Skype and all of a sudden an alarm in your building sets off. The original version of the Stroop task required participants to respond vocally to the ink color of the stimulus (i.e., a word denoting a color), so that a response dimension overlap occurred with both the relevant (i.e., the ink color) and the irrelevant stimulus dimensions (i.e., the meaning of the word denoting the color). For this reason, in Kornblum’s latest taxonomy[4], the “Stroop effect”, which is produced by the classical Stroop task, is a Type-8 effect. The term Type-4 effect, which is defined by a sole S-S overlap, only applies to those versions of the Stroop task in which subjects respond manually

Objectives

Results

Conclusion