Hemispheric differences in processing Stroop-type visual patterns

Abstract

A brief review of the literature on hemispheric differences is initially presented with special emphasis on the process-oriented theory which suggests that the left hemisphere (LH) processes analytically and the right hemisphere (RH) holistically.

The purpose of the thesis was to test the analytic(LH)/ holistic (RH) theory. The main technique used involved a matching task ("Same-Different") with tachistoscopic presentations with male and female groups of right-handed subjects In addition, three experiments were run involving simple reaction time responses.

The stimuli employed to test the theory were Stroop-type visual patterns (letters and arrows) comprising elements at both global and local levels.

In Experiment 1 (global letter matching), the LH generated a Stroop effect revealing analytic mechanisms while the RH showed no such effect revealing holistic strategies.

In Experiment 2 (local letter matching) and in Experiments 3, 4, 5and 6 (global and local letter matching) the results showed that both hemispheres can process analytically when "forced". Some results indicated the possibility of certain variables affecting the RH's analytic processing more than the LH's suggesting that some differences in efficiency of analytic processing between the two hemispheres may exist.

Experiments 7--13 tested the theory with different and lessverbally codable material (arrows) than the letter stimuli. The results in the local matching experiment confirmed the finding that both hemispheres when "forced", can apply analytic strategies. The results of the other arrow experiments suggested that it is possible in certain experimental conditions to demonstrate holistic processing not only by the RH but also by the LH. Alternative interpretations were however possible.

It is concluded that the dichotomy of the LH processing analytically and the RH holistically is not maintained,