ABSTRACT
The concept of hemisphere-specific processing competence, however, does not seem to exhaust all of the implications of terms such as "cerebral dominance" or "leadership." The possibility of interhemispheric conflicts is indeed suggested by phenomena such as diagonistic dypspraxia observed in split-brain patients. The notion of interhemispheric rivalry, however, has also been applied to the intact brain. Thus the problem of cerebral dominance, considered as decisional dominance, independent of specific functional competences, has to be faced on at least one front. Similarity judgments between multivariate stimuli, by apparently implying an optional performance, might in principle reflect the coexistence of alternative cognitive rules, of which one may, for a variety of reasons, be dominant. A possibility to be considered is that, independent of the way in which the instructions are given, the complexity of the algorithm inherent in some tasks may be such as to require a propositional mediation afforded by the left hemisphere.
