PubMed1978
The dichhaptic stimulation procedures developed by Witelson (1974) for the study of brain lateralization in children were modified and extended for use with adults. Consistent with findings in children, an overall left hand advantage was found under conditions of simultaneous or dichhaptic stimulation, although it was not found under conditions of monohaptic stimulation. The major purpose of the study was to determine whether in adults hand differences (assumed to reflect hemisphere utilization) could be influenced by the use of differential problem-solving strategies. Half the Ss were instructed to approach the haptic learning and recognition problems in a "sequential" or "analytic" manner, and half to approach them in a "holistic" or "Gestalt" manner. The results indicated that the degree of left hand superiority was indeed influenced by this manipulation, although it is to be noted that the actual basis of the effect is unclear. The results were consistent with the idea that brain lateralization must be defined, not strictly by tasks, but by strategies used by subjects to perform the tasks used to detect and study that lateralization. It is suggested that this immensely complicates the issue of interpreting the origin and basis of individual and group differences in laterality effects.