Some historical notes orienting towards brain mechanisms that could underlie hemispheric asymmetries

Abstract

The first minor aim of this synthetical historical survey consisted in showing that the discovery of the internal organization of language within the left hemisphere has been mainly determined by theoretical models and cultural factors, whereas the discovery of the left lateralisation of language and of the right lateralization of emotions and of other cognitive and perceptual functions has been mainly determined by empirical observations. A second more relevant aim of the survey consisted in discussing historical and more recent data suggesting that the different lateralisation of language and emotions has influenced not only the asymmetrical representation of other cognitive, affective and perceptual functions, but also (thank to the shaping influence of language on human cognition) of asymmetries regarding more general aspects of thought (such as the distinctions between 'propositional vs automatic' and 'conscious vs unconscious' ways of functioning). In the last part of the review, these data will be included in a more general discussion, concerning the brain functions that could be subsumed by the right hemisphere for three main reasons: (a) to avoid conflicts with the language mediated activities of the left hemisphere; (b) because of unconscious and automatic aspects of its non-verbal organisation or (c) due to the competition for cortical space determined by the development of language within the left hemisphere.

Keywords: Conscious/unconscious; Emotional/cognitive systems; Language shaped activities; Propositional/automatic; Right hemispheric syndromes.