Individual Differences in Verbal and Spatial Stroop Tasks: Interactive Role of Handedness and Domain.

Mariagrazia Capizzi,Ettore Ambrosini,Antonino Vallesi

doi:10.3389/fnhum.2017.00545

Abstract

A longstanding debate in psychology concerns the relation between handedness and cognitive functioning. The present study aimed to contribute to this debate by comparing performance of right- and non-right-handers on verbal and spatial Stroop tasks. Previous studies have shown that non-right-handers have better inter-hemispheric interaction and greater access to right hemisphere processes. On this ground, we expected performance of right- and non-right-handers to differ on verbal and spatial Stroop tasks. Specifically, relative to right-handers, non-right-handers should have greater Stroop effect in the color-word Stroop task, for which inter-hemispheric interaction does not seem to be advantageous to performance. By contrast, non-right-handers should be better able to overcome interference in the spatial Stroop task. This is for their preferential access to the right hemisphere dealing with spatial material and their greater inter-hemispheric interaction with the left hemisphere hosting Stroop task processes. Our results confirmed these predictions, showing that handedness and the underlying brain asymmetries may be a useful variable to partly explain individual differences in executive functions.

Highlights

‘‘I may be left-handed, but I’m always right!’’ is just one of the many quotes that circulate on the web ironically attesting that left-handedness has been traditionally associated with negative value and connotation
These results indicate that in the verbal domain the Stroop effect was reduced for participants with more positive Edinburgh Handedness Inventory (EHI) scores, whereas in the spatial domain the Stroop effect was reduced for participants with less positive scores
The general linear model (GLM) analysis revealed a significant interaction between cognitive domain and direction of handedness (F(1,285) = 12.78, p < 0.001, ηp2 = 0.04), confirming that the verbal and spatial Stroop effects were predicted by the EHI scores in an opposite way

Summary

Introduction

‘‘I may be left-handed, but I’m always right!’’ is just one of the many quotes that circulate on the web ironically attesting that left-handedness has been traditionally associated with negative value and connotation. ICH exhibit superior performance on tasks that require access to right-hemisphere processes and that implicate inter-hemispheric interaction, such as memory retrieval and belief updating/cognitive flexibility tasks (e.g., Jasper and Christman, 2005; Propper et al, 2005; Lyle et al, 2012) Overall, these findings have been taken as evidence for the argument that ‘‘consistent vs inconsistent handedness is associated with decreased vs increased interhemispheric interaction and with decreased vs increased right hemisphere access, respectively’’ A robust finding that emerges in the Stroop task is the so-called ‘‘Stroop effect’’, which refers to a drop in performance in incongruent compared to congruent color-word matching

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Conclusion