Lateralisation of language processing – right hemisphere contribution to understanding and analysing language

Despite the fact that in 96% of right-handed adults the left hemisphere is dominant for language processing (its lesions lead to severe impairment of both perception and production of the language) there is research proving that processes occurring in the right hemisphere also take part in language processing. In this article, I would like to revise the contribution of the right hemisphere for language processing and try to demonstrate the underlying collaboration of the left and right hemispheres. One of the possible models describing the involvement of both hemispheres in language is Bilateral Activation Integration and Selection theory. It is based on the concept of sematic fields of different range distinguishing two ways of encoding the meaning – the left hemisphere processes underlie the fine semantic interpretation while the right hemisphere processes support relatively more coarse coding. In explaining the mechanisms of bilateral collaboration in language processing, we may also relate to GSH (Gradet Salience Hypothesis), which describes the differences in processing well-known expressions, stored in the left-hemisphere lexicon, and novel expressions (e.g. metaphors one has never come across before) engaging right-hemisphere processes. Both of these theories form a theoretical background for research on the linguistic processes that engage bilateral structures. One of those cases is metaphor processing, which requires detachment of the main meaning and referring to coarser semantic associations. We can also observe differences in bilateral activations in concrete and abstract word processing and in the research on context-related associations between words.