Hemisphere specific effects in reasoning performance

Summary

Subjects frequently produce matching responses to Wason's selection problem. Some authors have proposed that such responses are a result of information processing functions which are lateralised to the right hemisphere and that compete with left hemisphere verbal/logical processes for the control of overt responding. Support for this position has come mainly from studies of patient populations. The present paper reports a series of experiments in which attempts were made to obtain similar confirmation from normal subjects using the technique of selective hemispheric interference. Subjects worked on the selection problem while concurrently performing a unimanual balancing task. Weak but persistent effects of hemispheric interference on the pattern of responses th the selection porblem were observed. In general, the data are consistent with the hypothesis that matching responses reflect right hemisphere processing.