The role of hemispheric specialization in the analysis of stroop stimuli

Abstract

Previous work on the functions of the two cerebral hemispheres has suggested that whereas the non-dominant hemisphere may only process information on a visual basis, the dominant hemisphere may process information both visually and in terms of verbal content. This would imply that if visual and verbal content were in conflict, processing in the dominant hemisphere may require resolution of the conflict, while processing in the non-dominant hemisphere could be carried out on the basis of visual information alone, without interference from the verbal content.An experiment was carried out to investigate this possibility using STROOP colour words, presented in either the left or right visual field. On the basis of the above assumption: 1.(1) Under instructions ‘respond to colour’, signals presented to the dominant hemisphere should be responded to less readily than signals presented to the non-dominant hemisphere, if the colour and colour-name are in conflict.2.(2) Under instructions ‘respond to name’, signals presented to either hemisphere should lead to confusion if colour and colour-name do not match, since whichever hemisphere the signals are presented to, verbal analysis could only take place in the dominant hemisphere.A manual button-pressing response was used to record the reaction times of subjects responding to STROOP colour words under the two kinds of instruction given above.Results are presented which demonstrate differences between the two hemispheres in the time required to classify on the basis of colour-name and which show greater interference in the dominant hemisphere produced by incompatible colour and colour-name information.