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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.
Meaning of a module
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.
No singular anatomical module
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.
No double dissociation – acquired or developmental
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.
However, other evidence from developmental studies has been presented (most famously by Pinker) as supporting a language module, namely the purported dissociation between Specific Language Impairment (SLI), where language is disrupted whilst other mental abilities are not, and Williams Syndrome (WS) where language is said to be spared despite severe mental deficits. More recent and empirically robust work has shown that these claims may be inaccurate, thus, considerably weakening support for dissociation. For example, work reviewed by Brock and Mervis and Beccera demonstrated that language abilities in WS are no more than would be predicted by non-linguistic abilities. Further, there is considerable debate concerning whether SLI is actually a language disorder or whether its aetiology is due to a more general cognitive (e.g. phonological) problem. Thus, the evidence needed to complete the picture for modularity – intact language coupled with gross intellectual deterioration – is not forthcoming. Consequently, developmental data offers little support for the notion that language processing occurs within a module.
Thus, the evidence from double dissociations does not support modularity, although it should be noted that lack of dissociation is not evidence against a module; this inference cannot be logically made.
Lack of information encapsulation
Indeed, if language were a module it would be informationally encapsulated. Yet, there is evidence to suggest that this is not the case. For instance, in the McGurk effect, watching lips say one phoneme whilst another is played creates the percept of a blended phoneme. Further, Tanenhaus, Spivey-Knowlton, Eberhard and Sedivy (1995) demonstrated visual information mediating syntactic processing. In addition, the putative language module should process only that information relevant to language (i.e., be domain-specific). Yet evidence suggests that areas purported to subserve language also mediate motor control and non-linguistic sound comprehension. Although it is possible that separate processes could be occurring but below the resolution of current imaging techniques, when all this evidence is taken together the case for information encapsulation is weakened.
The alternative, as it is framed, is that language occurs within a more general cognitive system. The counterargument is that there appears to be something ‘special’ about human language. This is usually supported by evidence such as all attempts to teach animals human languages to any great success have failed (Hauser et al. 2003) and that language can be selectively damaged (a single dissociation) suggesting proprietary computation may be required. Instead of postulating 'pure' modularity, theorists have opted for a weaker version, domain-specificity implemented in functionally specialised neural circuits and computation (e.g. Jackendoff and Pinker’s words, we must investigate language “not as a monolith but as a combination of components, some special to language, others rooted in more general capacities”).
The debate is ongoing.
- Coltheart, M. (1999). Modularity and cognition. Trends in Cognitive Sciences, 3, 115–120
- Bryson, J. J. (2002). Language isn’t quite that special. Brain and Behavioral Sciences, 25 (6), 679–680
- Fodor, J. A. (1983). The Modularity of Mind. Bradford Books. MIT Press, Cambridge, MA
- Flombaum, J. I., Santos, L. R., & Hauser, M. D. (2002). Neuroecology and psychological modularity. Trends in Cognitive Sciences, 6 (3), 106–108
- Calabretta, R., Di Ferdinando, A., Wagner, G. P., & Parisi, D. (2003). What does it take to evolve behaviorally complex organisms? BioSystems, 69, 245–262
- Wada, J., & Rasmussen, T. (1960). Intracarotid injection of Sodium Amytal for the lateralization of cerebral speech dominance. Experimental and clinical observations. Journal of Neurosurgery, 17, 266–282
- Martin, R. C. (2003). Language processing: Functional organization and neuroanatomical basis. Annual Review of Psychology, 54, 55–90
- Binder, J., & Price, C. (2001). Functional imaging of language. In R. Cabeza and A. Kingstone (Eds.), Handbook of Functional Neuroimaging of Cognition (pp. 187–251). Cambridge, MA: MIT Press
- Robertson, D. A., Gernsbacher, M.A., Guidotti, S.J., Robertson, R.R., Irwin, W., Mock, B.J., & Campana, E. (2000). Functional neuroanatomy of the cognitive process of mapping during discourse comprehension. Psychological Science, 11, 255–60
- Grodinsky, Y. (2006). The language faculty, Broca’s region, and the mirror system. Cortex, 42 (4), 464–468
- Pinker, S. (1997). How The Mind Works. Harmondsworth: Penguin
- von der Malsburg, C. (1995). Binding in models of perception and brain function. Current Opinion in Neurobiology, 5, 520–52
- Dunn, J. C., & Kirsner, K. (2003). What can we infer from double dissociations? Cortex, 39, 1–7
- Coltheart, M., & Davies, M. (2003). Inference and explanation in cognitive neuropsychology. Cortex, 39, 188–191
- Moscovitch, M. & Umiltà, C. (1990). Modularity and neuropsychology: implications for the organization of attention and memory in normal and brain-damaged people. In M. F. Schwartz (Ed.), Modular Deficits in Alzheimertype dementia. Cambridge, MA: MIT Press
- Goodglass, H., & Kaplan, E. (1972). The Assessment of Aphasia and Related Disorders. Philadelphia, PA: Lea & Febiger
- Levy, Y. (1996). Modularity of language reconsidered. Brain & Language, 55 (2), 240–263
- Pinker, S. (1994). The language instinct: How the mind creates language, pp. 37–43. New York: W. Morrow
- van der Lely, H. K. J. (2005). Domain-Specific Cognitive Systems: Insight from Grammatical Specific Language Impairment, Trends in Cognitive Sciences, 9 (2), 53–59
- Bellugi, U., Marks, S., Bihrle, A., & Sabo, H. (1988). Dissociation between language and cognitive functions in Williams syndrome. In D. Bishop and K. Mogford (Eds.), Language development in exceptional circumstances (pp. 177–189). London: Churchill Livingstone
- Brock, J. (2007). Language abilities in Williams syndrome: A critical review. Development and Psychopathology, 19, 97–127
- Mervis, C. B., & Beccera, A. M. (2007). Language and communicative development in Williams Syndrome. Mental Retardation and Developmental Disabilities Research Reviews, 13, 3–15
- Norbury, C., Bishop, D. V. M., & Briscoe, J. (2001). Production of English finite verb morphology: A Comparison of SLI and mildmoderate hearing impairment. Journal of Speech, Language and Hearing Research, 44, 165–178
- Leonard, L. 1998, Children with Specific Language Impairment. Cambridge, Massachusetts: MIT Press
- Bishop, D. V. M. (1994). Grammatical errors in specific language impairment: Competence or performance limitations. Applied Psycholinguistics, 15, 507–550
- Kail, R. (1994). A method for studying the generalized slowing hypothesis in children with specific language impairment. Journal of Speech and Hearing Research, 37, 418–421
- McGurk, H., & MacDonald, J. (1976). Hearing lips and seeing voices. Nature, 264 (5588), 746–748
- Carston, R. (1996). The architecture of the mind: modularity and modularization. In D. Green et al. (Eds.), Cognitive Science: An Introduction (pp. 53–83). Cambridge: Blackwell
- Heiser, M., Iacoboni, M., Maeda, F., Marcus, J., & Mazziotta, J.C. (2003). The essential role of Broca's area in imitation. European Journal of Neuroscience, 17, 1123–1128
- Saygin, A. P., Dick, F., Wilson, S. M., Dronkers, N. F., & Bates, E. (2003). Neural resources for processing language and environmental sounds: Evidence from aphasia. Brain, 126 (4), 928–945
- Rumelhart, D. E., & McClelland, J. L. (1986) PDP models and general issues in cognitive science. In D. E. Rumelhart, J. L. McClelland, and the PDP Research Group (Eds.), Parallel distributed processing: Explorations in the microstructure of cognition. Volume 1: Foundations. Cambridge, MA: Bradford Books/MIT Press
- Pinker, S., & Jackendoff, R. (2005). The faculty of language: What’s special about it? Cognition, 95, 201–236
- Pulvermuller, F. (2003). The Neuroscience of Language. On Brain Circuits of Words and Serial Order. UK, Cambridge: Cambridge University Press
- Jackendoff, R. & Pinker, S. (2005) The nature of the language faculty and its implications for evolution of language (Reply to Fitch, Hauser, & Chomsky) Cognition, 97 (2), 211–225, page 223
- Altmann, G. T. M. (2001). The mechanics of language: Psycholinguistics in review. The British Journal of Psychology, 92, 129–170.
- Bauer, R. M., & Zawacki, T. (2000). Auditory Agnosia and Amusia. In M.J. Farah and T.E. Feinberg (Eds.), Patient-Based Approaches to Cognitive Neuroscience, (pp. 97–106). New York: McGraw-Hill.
- Breedin, S. D., & Saffran, E. M. (1999). Sentence processing in the face of semantic loss: A case study. Journal of Experimental Psychology: General, 128, 547–62.
- Breedin, S. D., Saffran, E. M., & Coslett, H. B. (1999). Reversal of the concreteness effect in a patient with semantic dementia. Cognitive Neuropsychology, 11, 617–60.
- Colledge, E., Bishop, D., Koeppen-Schomerus, G., Price, T., Happe, F., Eley, T., Dale, P. S., & Plomin, R. (2002). The structure of language abilities at 4 years: A twin study. Developmental Psychology, 38, 749–757.
- Dapretto, M., & Bookheimer, S. Y. (1999). Form and content: Dissociating syntax and semantics in sentence comprehension. Neuron, 24, 427–32.
- Fodor, J. A. (1983). The Modularity of Mind. Bradford Books. MIT Press, Cambridge, MA.
- Garrard, P., Carroll, E., Vinson, D. P., & Vigliocco, G. (2004). Dissociating lexico-semantics and lexico-syntax in semantic dementia. Neurocase, 10, 353–362.
- Grafman, J., Passafiume, D., Faglioni, P., & Boller, F. (1982) Calculation disturbances in adults with focal hemispheric damage. Cortex, 18, 37–50.
- Griffiths T. D., Rees, A., & Green, G. G. R. (1999). Disorders of human complex sound processing. Neurocase, 5, 365–378
- Hauser, M. D., Chomsky, N., & Fitch, W. T. (2002). The faculty of language: What is it, who has it, and how does it evolve? Science, 298, 1569–1579.
- Hickok, G., & Poeppel, D. (2000). Towards a functional neuroanatomy of speech perception. Trends in Cognitive Sciences, 4 (4), 131–138.
- Hill, E. L. (2001). Non-specific nature of specific language impairment: A review of the literature with regard to concomitant motor impairments. International Journal of Language & Communication Disorders / Royal College of Speech & Language Therapists, 36 (2), 149–171.
- Kahn, H. J., & Whitaker, H.A. (1991). Acalculia: an historical review of localization. Brain Cognition, 17, 102–15.
- Luzzatti, C., Aggujaro, S., & Crepaldi, D. (2006). Verb-noun double dissociations in aphasia: Theoretical and neuroanatomical foundations. Cortex, 42 (6):875–83.
- Marcus, G. F. (2006). Cognitive Architecture and Descent with Modification. Cognition, 101, 443–465.
- Marslen-Wilson, W.D., & Tyler, L.K. (1987). Against modularity. In J. L.Garfield (Ed.), Modularity in Knowledge Representation and Natural Language Understanding. Cambridge, Mass: MIT Press.
- Martins, I.P. & Farrajota, L. (in press). Proper and common names: A double dissociation. Neuropsychologica.
- Mattys, S. L., Melhorn, J. F., & White, L. (in press). Effects of syntactic expectations on speech segmentation. Journal of Experimental Psychology: Human Perception and Performance.
- Mattys, S.L., Pleydell-Pearce, C. W., Melhorn, J.F., & Whitecross, S.E. (2005). Detecting silent pauses in speech: A new tool for measuring on-line lexical and semantic processing. Psychological Science, 16, 958–964.
- Miozzo, M., & Gordon, P. (2005). Facts, Events, and Inflection: When Language and Memory Dissociate. Journal of Cognitive Neuroscience, 17, 1074–1086.
- Moss, H. E., Abdallah, S., Acres, K., Fletcher, P., Pilgrim, L., & Tyler, L. K. (2003). The role of the left inferior frontal gyrus in semantic selection and competition. Journal of Cognitive Neuroscience, 15, Suppl. A161.
- Patterson, K. E., & Marcel, A. J. (1977). Aphasia, dyslexia, and phonological coding of written words. Quarterly Journal of Experimental Psychology, 29, 307–318.
- Poeppel, D. (2001). Pure word deafness and the bilateral processing of the speech code. Cognitive Science, 21 (5), 679–693.
- Raichle, M.E. (1988). Positron emission tomographic studies of the cortical anatomy of single-word processing. Nature, 331, 585–589.
- Rosselli, M.; Ardila, A. (1989). "Calculation deficits in patients with right and left hemisphere damage". Neuropsychologia. 27 (5): 607–617. doi:10.1016/0028-3932(89)90107-3.
- Tanenhaus, M. K., Spivey-Knowlton, M. J., Eberhard, K. M., Sedivy, J. C., Allopenna, P. D., & Magnuson, J. S. (1996). Eye movements and spoken language comprehension. In the Proceedings of the 34th Annual Meeting of the Association for Computational Linguistics.
- Thomas, M., & Karmiloff-Smith, A. (2002). Are developmental disorders like cases of adult brain damage? Implications from connectionist modelling. Behavioral and Brain Sciences, 25, 727–788.
- Tooby, J., & Cosmides, L. (1992) The psychological foundations of culture. In J. Barkow, L. Cosmides, & J. Tooby (Eds.), The adapted mind: Evolutionary psychology and the generation of culture (pp. 19–136). Oxford: Oxford University Press.
- Trout, J. D. (2001). The biological basis of speech: what to infer from talking to the animals. Psychological Review, 108 (3), 523–549.
- Vouloumanos, A., Kiehl, K., Werker, J.F., & Liddle, P. (2001). Detecting sounds in the auditory stream: Event-related fMRI evidence for differential activation to speech and non-speech. Journal of Cognitive Neuroscience, 13 (7), 994–1005.
- Wang, E., Peach, R. K., Xu, Y., Schneck, M., & Manry, C. (2000). Perception of dynamic acoustic patterns by an individual with unilateral verbal auditory agnosia. Brain and Language, 73, 442–455.
- Warren, R. M., & Warren, R. P. (1970). Auditory illusions and confusions. Scientific American, 223, 30–36.
- Warrington, E.K. (1981). Neuropsychological studies of verbal semantic systems. Philos. Trans. R. Soc. Lond. B. Biol. Sci., 295, 411–23.
- Zeki S. (2005). The Ferrier Lecture 1995 behind the seen: The functional specialization of the brain in space and time. Philos. Trans. R. Soc. Lond. B. Biol. Sci., 360, 1145–83.