p. 124-5)
One way of trying to understand the structures and functioning of the brain is dividing the brain into cognitive modules. As much as there is an ongoing speculation whether cognitive modules exist, they do offer a basis for possible explanation of brain functioning. Two contrasting theories explain the brain functioning from different perspectives particularly how the cognitive modules develop. First of them is Innate modularity argued from the nativist point of view by Fodor (1983). He argues that modularity of the brain is innate, humans are born with 'pre-fabricated' brain's ability to function in a particular way and are not affected by environments. He claims that this happened as an outcome of long-term evolution of the species and allows humans to be able to use such innate dispositions to make sense of the world. (Mareschal et al., 2004, p.127)
On the other hand Karmiloff-Smith (1992) argues that cognitive modules are a product of development and the affect of environment interaction and stimulation. She uses the plasticity of the brain as a strong indicator that different parts of the brain may overtake the function of other part of the brain if necessary at an early age which confronts the nativist idea of innate local functioning. There is an ongoing argument between these two theories.
Depending on which view we look at this argument from it may put some points in favour of both. If we were to look at it form the genetic and molecular point of view such as Rakic (1988), then the evidence from other organs in our bodies would point in favour of Fodor's theory. And it surely can be applied in pre-natal period of the brain development. However the evidence gathered through modern technology shows that the most important neural activity happening in the brain after the birth is the main factor influencing the development of the brain. As supported by Petersen et al. (1990) and their experiment using PET scan and test of English words with native and foreign speakers which showed that particular part of cortex in native speakers responded to English words. This suggests that the exposure to same environment led to the development of a particular processing area in the cortex of their left hemisphere to process English language. The results of this experiment support the 'modularization' theory. (Mareschal et al., 2004, p. 130)
As much as modern technology helps to find evidence, some forms of it may not be suitable for young children as their affects on children's health are not known and may be harmful. Future possibilities of open scans may allow for more research in this area.
Karmiloff-Smith (1992) also introduces the theory of self-organizing system based on the ability of the brain to organize information into structures when exposed to a particular environment. Based on the theory of Hebb (1949) which states that in order for the localized functions to work simultaneously and being able to create particular pathways an important rule of repetition comes into place. The Hebb rule states that the links created by neurons to transmit information are strengthened by its repeated use and so support the theory of 'selectionism'.
Although the evidence is complex it is more in favour to support the theory of Karmiloff-Smith (1992) and is best demonstrated on experiments and studies carried out on the ability of children to learn language. On the side of nativists, Chomsky (1965) claims that language is innate and to support this further Pinker 1994() claims that pidgins and creoles are some of the evidence for this. His claim is drawn from the evidence which shows that children are able to create grammatically correct language though they never heard it being spoken before. Chomsky's 'argument from the poverty of the input' suggesting that children can create a 'new language' such as well formulating never before heard question. He also claims that the brain has got a special set of genes allowing for language to develop in particular cortical region.
In contrast to Pinker's claims, the evidence from neuroscience and particularly the study carried out by Neville et al. (1998) shows that although in adulthood there are specialist cortical regions processing language it is not inevitable that these functions have to be carried out in these areas of the cortex. The experiment Neville et al. carried out with deaf and hearing participants showed that in deaf participants the same area of language processing was activated as in the hearing participants and in addition to it a larger part of the region on the right hemisphere was activated. These findings indicate that other areas of the brain are capable of supporting language related information processing. (ref. p. 140) It also links the debate with equipotentiality which means that left and right hemispheres have got the same potential for developing language.
Further evidence comes from Reilly et al. (1998) and their study carried out on children with localized brain damage in the area of language processing that happened early after or during the birth. The results of their study showed that although the learning capacity of the children was not sustained at the same level for all developmental periods and was rather varied, it showed a pattern of ongoing functional recovery of the damaged area by being taken over by the undamaged areas of the cortex. Other studies of adults with brain damage showed that localized lesions causing particular loss of certain capabilities are more or less permanent. This suggests that in adulthood the plasticity of the brain decreases and functions cannot be 'transferred' elsewhere.
Also the study of Johnson et al. (1996) concerning the functional ability of pre-frontal region of cortex is in support of 'modularization'. The study was carried out on infants with results suggesting that cognitive and behavioural development of infants can be linked to pre-frontal cortex and that it is especially associated with learning new skills in early stages of development. This shows that the role of the pre-frontal cortex is more general in early development and capable of taking on other functions if these are not accessible in other parts of the cortex. This changes as the functions in the cortex are further specialized and localized and the role of pre-frontal cortex decreases.
Evidence here presented shows that the nativist viewpoint is supported to certain extent by cognitive neuroscience but is outweighed by evidence of plasticity and the ability of other regions of the brain taking over the damaged areas in early development if needed without need of 'pre-specification'. This shows that in typical or atypical development that may be caused by localized damage to the brain seems to be the a product of development supporting the theory of 'modularization'.
Bridging the gap between physical structure of the brain and its function proves to be a major challenge. It is certainly difficult to prove which of the two theories is right as it shows that both of them seems to be correct in particular aspects of the research and different evidence supports both of them. Although some of the evidence points in favour of innate modularity theory more of the evidence suggests that modularization theory is more at place. It is still argued between these two theories whether the functioning of the brain is innate and 'pre-fabricated' from birth or whether the environment plays important role in the development of localized functioning. Evidence presented in this essay clearly indicates that modularization is supported more than innate modularity. Even with the help of modern technology scientist are still unable to specify which of the theories may be more or less correct and the ongoing argument is so yet to be settled.
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References
Lewkowitz, D. J., Turkewitz, G. (1981) cited in Mareschal et al. (2004), p. 124
Meltzoff, A. N., Borton R. W. (1979) cited in Mareschal et al. (2004), p. 124
Fodor, J. A. (1983) cited in Mareschal et al. (2004), p. 127-129
Karmiloff-Smith, A. (1992) cited in Mareschal et al. (2004), p. 127-129
Rakic, P. (1988) cited in Mareschal et al. (2004), p. 129
Petersen, S. E., Fox, P. T., Snyder, A. Z. and Raichle, M. E. (1990) cited in Mareschal et al. (2004),
p. 130
Hebb, D. O. (1949) cited in Mareschal et al. (2004), p. 133
Pinker, S. (1994) cited in Mareschal et al. (2004), p. 135-138
Chomsky, N. (1965) cited in Mareschal et al. (2004), p. 135-138
Neville, H. J., Bavelier, D., Corina, D et al. (1998) cite in Mareschal et al. (2004), p. 140-142
Johnson, M. H., Tucker, L. A., Stiles, J. and Turner, D. (1998) cited in Mareschal et al. (2004), p. 147
Reilly, J. S., Bates, E. A. and Marchman, V. A. (1998) cited in Mareschal et al. (2004), p. 140
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, Oxford, Blackwell/The Open University
A clearly argued conclusion. It would be good to develop your critical analysis in more detail.