These structural modules are known as neural modules and are real. There are also hypothetical cognitive modules which attempt to explain how the different neural modules work. Fodor (1983) believed that cognitive modules existed and that these were innately predetermined (nativist viewpoint). He believed that the brain worked like an information processor, it receives inputs and processes them and the environment which an individual child is in does not affect this process. Fodor’s theory believes that the modules are domain specific and encapsulated (each module performs its own task regardless of what may be happening to other modules). He also believed that this process was mandatory (no conscious control) and due to these properties were very efficient.
This theory is disputed by Karmiloff-Smith (1992) who also believed that cognitive modules exist but believed that the modules were more epigenetic and that the environment which a child is in can affect the development of the modules (constructivist viewpoint). She hypothesised that the cognitive modules have a genetic predisposition to perform a certain role which allows for flexibility within the system through interactions with the environment. In other words that modules are created because of the child’s development and interactions with the environment.
Fodor’s hypothesis would infer that if the language area of the brain was damaged that no other part of the brain could take over this function. This is not the case and it has been shown that other areas of the brain can take over this function (Reilly et al. 1998). This would seem to indicate that Karmiloff-Smith’s theory holds more weight as it is the brain’s interaction with the environment through the stimulation of neuron pathways that ensures that another part of the brain takes over the language unit. It seems that perhaps the brain has an innate predisposition to develop functions in a certain area and that if this is not possible it has the plasticity to adapt.
This seems to indicate that the brain is capable of organising itself. Johnson (1997) hypothesised that all brain development depends upon self-organisation and that it is through small changes in the brain that a pattern begins to develop. One of these adjustments is Hebb’s (1949) rule which suggests that when two neurons repeatedly activated the synaptic resistance between them is lowered which makes it easier and more likely that the activation will occur. This is similar to selectionism discussed earlier and provides a reason as to why continual use of a pathway increases the likelihood of the pathway continuing. The whole process in dependant upon each localised neural pathways organising in such a way so that the end result is a coherent ‘whole’ (Mareschal et al., 2004).
If it is the case that the brain self-organises then there are initially millions of different pathways which could achieve a similar result. If viewed from Fodor’s point of view this would mean that the genes had already mapped out the best pathway amongst these many choices which is a lot of pathways to have stored in the genetic blueprint. Another aspect in favour of Karmiloff-Smith is that it seems unnecessary for the brain to produce so many possible pathways if the best one is already predetermined by the genetic blueprint unless the system is allowing for plasticity and possible avoidance of damaged areas.
Language in most adults is centred in the left-hemisphere of the brain. Pinker (1994) hypothesised that within the brain there was an innate specific area for language, a language seat and that possibly there were special genes which helped connect this area together. Pinker believed that language was inevitable and he drew on four sources of evidence for his case, the existence of pidgens and creoles, observations of the ‘poverty of input’, grammatical formulations and evidence about brain structure and function. The first of his arguments is that children who grow up in a society which speaks a pidgin language they develop a grammatical form of that language (creole). Pinker’s argument is the idea that the children had an innate predisposition to form creole even though they hadn’t heard it during their development. This provides a strong case for the innate theory as the environment cannot have provided grammatical input in that language. An argument to this could be that the children may have heard grammar in the native language used by those who were speaking pidgin. The second element is associated with the fact that children create new questions even though they may not have heard them before. This aspect involves the children understanding grammatical rules which they haven’t been taught. Although Pinker argues that this is innate it may through the child’s interactions with the environment that they formulate grammatical rules. The third argument is that many languages in the world use auxiliary verbs and also move them to the beginning of a sentence to form a question. Pinker believes that because so many different languages around the world do this that it is evidence for an innate predisposition for the human race to develop in this way. The final aspect, brain structure and function will be covered in more detail later in this essay.
Pinker’s theory is in line with Fodor’s view that brain areas are genetically predetermined. If this is the case then if the language area of the brain was damaged then language development would be impaired. Alternatively if a child is born with both hemispheres of the brain capable of supporting language (equipotentiality) then Karmiloff-Smith’s view would be more reasonable. In ‘normal’ development the left-hemisphere of the brain is responsible for language in an adult so to try and discover whether there is equipotentiality ‘atypical’ language developments need to be considered to establish if the right-hemisphere can play a part in the language process.
Neville et al. (1998) compared the brain regions involved in processing language between deaf and hearing children. In both groups the left-hemisphere of the brain was activated however for the deaf group the right-hemisphere was also activated. This would seem to infer that both sides of the brain can be used for language. It is worth noting though that the right-hemisphere is associated with spatial aspects (Sousa, 2001) so it is not that surprising that this hemisphere is activated in deaf children who would be used to using visual-spatial skills in sign language. So from this evidence it is difficult to conclude that either the nativist or constructivist viewpoint provides a more conclusive explanation.
Further research (Reilly et al, 1998) compared grammatical and narrative skills of children which either had left hemisphere or right hemisphere focal lesions, to a control group. They found that although children who had brain damage were developmentally behind the control group but there was no significant difference between the performance of the children with right-hemisphere and left-hemisphere damage. This would seem to indicate that the right-hemisphere is capable of supporting language development and possibly supports the notion of equipotentiality. If this is the case then this could be seen as evidence for Karmiloff-Smith’s ideas of modules forming due to development and the brain self-organising itself around the damaged areas.
Stiles and Thal (1993) longitudinally studied children which had focal lesions on either the left or right hemisphere. Language delays were found in all the children however children who had right-hemisphere damage showed significant delays in word comprehension. This is surprising as in adults the left-hemisphere is responsible for language so expectations would be that those with left-hemisphere damage would be having more difficulties. It would be expected therefore that children with damage to the left-hemisphere would demonstrate more difficulty in this area. One explanation could be that the brain does not develop its language seat until later in life which may provide evidence for either viewpoint. An alternative explanation for these results could be that the left-hemisphere is trying to compensate for the damage to the other hemisphere and so language development is delayed while the brain adapts to the other functions it needs to perform. If this second option is the case then again it supports Karmiloff-Smith’s ideas and the brain is created with the ability to self-organise and have the ability due to plasticity to adapt to new situations at this age.
It is very hard to find unequivocal evidence for either the nativist or constructivist viewpoint. There must need to be some combination of the two in order to explain why in most adults the language seat is situated in the left-hemisphere but that individuals who have suffered damage to the left-hemisphere at a very young age still manage to learn and use language. One possibility is that the brain is created with a predisposition for developing certain skills in certain areas. If that area is not working for some reason then due to the brain’s plasticity other neurons can take over this function and form the necessary cognitive module. The evidence seems to indicate that there may initially or possibly permanently be some developmental delay but the brain does seem to be capable of compensating at this young age.
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References
Fodor, J (1983) cited in Mareschal, D., Johnson, M.H. and Grayson, A. (2004) pp 127-129.
Hebb, D.O. (1949) cited in Mareschal, D., Johnson, M.H. and Grayson, A. (2004) p 133.
Johnson, M.H. (1997) cited in Mareschal, D., Johnson, M.H. and Grayson, A. (2004) p132.
Karmiloff-Smith, A. (1992) cited in Mareschal, D., Johnson, M.H. and Grayson, A. (2004) pp 129-130.
Karmiloff-Smith, A. (1992) ‘Reading B: Beyond Modularity’ in Mareschal, D., Johnson, M.H. and Grayson, A. (2004) pp 158-161.
Mareschal, D., Johnson, M.H. and Grayson, A. (2004) ‘Brain and Cognitive Development’ in Oates, J. and Grayson, A. (eds) Cognitive and Language Development in Children, Milton Keynes, The Open University.
Neville, H.J., Mills, D. and Lawson, D. et al. (1998) cited in Mareschal, D., Johnson, M.H. and Grayson, A. (2004) pp 141-142
Pinker, S. (1994) cited in Mareschal, D., Johnson, M.H. and Grayson, A. (2004) pp 135-138.
Reilly, J.S., Bates, E.A. and Marchman, V.A. (1998) cited in Mareschal, D., Johnson, M.H. and Grayson, A. (2004) p 140.
Sousa, D.A. (2001) ‘How the Brain Learn second edition’, London, Sage Publications Ltd.
Stiles, L. and Thal, D (1993) cited in Mareschal, D., Johnson, M.H. and Grayson, A. (2004) p 142.
