|
Neuroconstructivism is a theory that states that gene–gene interaction, gene–environment interaction and, crucially, ontogeny are all considered to play a vital role in how the brain progressively sculpts itself and how it gradually becomes specialized over developmental time. Supporters of neuroconstructivism, such as Annette Karmiloff-Smith, argue against innate modularity of mind, the notion that a brain is composed of innate neural structures or modules which have distinct established evolutionarily developed functions. Instead, emphasis is put on innate domain relevant biases. These biases are understood as aiding learning and directing attention. Module-like structures are therefore the product of both experience and these innate biases. Neuroconstructivism can therefore be seen as a bridge between Jerry Fodor's psychological nativism and Jean Piaget's theory of cognitive development. ==Development vs. innate modularity== Neuroconstructivism has arisen as a direct rebuttal against psychologists who argue for an innate modularity of the brain.〔Fodor, J. (1983). ''The modularity of mind.'' Cambridge, MA: MIT Press.〕〔Pinker, S. (1994). ''The language instinct.'' London: Penguin.〕 Modularity of the brain would require a pre-specified pattern of synaptic connectivity within the cortical microcircuitry of a specific neural system. Instead, Annette Karmiloff-Smith has suggested that the microconnectivity of the brain emerges from the gradual process of ontogenetic development.〔〔Karmiloff-Smith, A. (1992). ''Beyond modularity: A developmental perspective on cognitive science.'' Cambridge, MA: MIT Press, Bradford Books.〕 Proponents of the modular theory might have been misled by the seemingly normal performances of individuals who exhibit a learning disability on tests. While it may appear that cognitive functioning may be impaired in only specified areas, this may be a functional flaw in the test. Many standardized tasks used to assess the extent of damage within the brain do not measure underlying causes, instead only showing the static end-state of complex processes. An alternative explanation to account for these normal test scores would be the ability of the individual to compensate using other brain regions that are not normally used for such a task.〔 Such compensation could only have resulted from developmental neuroplasticity and the interaction between environment and brain functioning. Different functions within the brain arise through development. Instead of having pre-specified patterns of connectivity, neuroconstructivism suggests that there are "tiny regional differences in type, density, and orientation of neurons, in neurotransmitters, in firing thresholds, in rate of myelination, lamination, ratio of gray matter to white matter," etc. that lead to differing capabilities of neurons or brain regions to handle specific functions. For example, the ventral and dorsal streams only arise because of innate differences in processing speed of neurons, not an innate selection to be either ventral or dorsal by the respective neurons.〔 Such a differentiation has been entitled a domain-relevant approach to development.〔〔 This contrasts the previous domain-general and domain-specific approaches. In the domain-general framework, differences in cognitive functioning are attributed to overarching differences in the neurons across the entire brain. The domain-specific approach contrasts this framework by arguing for inherent, specific differences within the genes which directly control a person's development. However, domain-specificity cannot be ruled out by neuroconstructivism.〔 Instead, it offers a developmental approach that focuses on change and emergent outcomes.〔 Such change leads to domain-specificity in adult brains, but neuroconstructivism argues that the key component of the specificity occurred from the domain-general start state.〔 Every aspect of development is dynamic and interactive.〔 Human intelligence may be more accurately defined by focusing on the plasticity of the brain and its interactions with the environment rather than inherent differences within the DNA structure. Dissociations seen in Williams syndrome or autism provide neuroscientists with a means of exploring different developmental trajectories.〔 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「neuroconstructivism」の詳細全文を読む スポンサード リンク
|