Language module

The language module is a hypothesized structure in the human brain or cognitive system that some psycholinguists such as Steven Pinker claim contains innate capacities for language. There is ongoing debate about this in the fields of cognitive science and neuroscience.

The debate on the issue of modularity in language is underpinned, in part, by different understandings of this concept. There is, however, some consensus in the literature that a module is considered committed to processing specialized representations (domain-specificity) (Bryson and Stein, 2001) in an informationally encapsulated way. A distinction should be drawn between anatomical modularity, which proposes there is one 'area' in the brain that deals with this processing, and functional modularity that obviates anatomical modularity whilst maintaining information encapsulation in distributed parts of the brain.

The available evidence points towards no one anatomical area solely devoted to processing language. The Wada test, where sodium amobarbital is used to anaesthetise one hemisphere, shows that the left-hemisphere appears to be crucial in language processing. Yet, neuroimaging does not implicate any single area but rather identifies many different areas as being involved in different aspects of language processing (Raichle, 1998) and not just in the left hemisphere. Further, individual areas appear to subserve a number of different functions (Raichle, 1998). Thus, the extent to which language processing occurs within an anatomical module is considered to be minimal. Nevertheless, as many have suggested, modular processing can still exist even when implemented across the brain; that is, language processing could occur within a functional module.

A common way to demonstrate modularity is to find a double dissociation. That is two groups: First, people for whom language is severely damaged and yet have normal cognitive abilities and, second, persons for whom normal cognitive abilities are grossly impaired and yet language remains intact. Whilst extensive lesions in the left hemisphere perisylvian area can render persons unable to produce or perceive language (global aphasia), there is no known acquired case where language is completely intact in the face of severe non-linguistic deterioration. Thus, functional module status cannot be granted to language processing based on this evidence.

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