Neuroconstructivism

Previous theories have supposed that genes are static unchanging code for specific developmental outcomes. However, new research suggests that genes may be triggered by both environmental and behavioral influences.[11] This probabilistic epigenesis view of development[12] suggests that instead of following a predetermined path to expression, genes are modified by the behavior and environment of an organism. Furthermore, these modifications can then act on the environment, creating a causal circle in which genes influencing the environment are re-influenced by these changes in the environment.

Cells do not develop in isolation. Even from a young age, neurons are influenced by the surrounding environment (e.g. other neurons).[13] Over time, neurons interact either spontaneously or in response to some sensory stimulation to form neural networks.[11] Competition between neurons plays a key role in establishing the exact pattern of connections.[14] As a result, specific neural activation patterns may arise due to the underlying morphology and connection patterns within the specified neural structures. These may subsequently be modified by morphological change imposed by the current representations. Progressively more complex patterns may arise through manipulation of current neuronal structures by an organism's experience.[11]

While neurons are embedded within networks, these networks are further embedded within the brain as a whole. Neural networks do not work in isolation, such as in the modularity of mind perspective. Instead, different regions interact through feedback processes and top-down interactions,[15] constraining and specifying the development of each region. For example, the primary visual cortex in blind individuals has been shown to process tactile information.[16] The function of cortical areas emerges as a result of this sensory input and competition for cortical space.[17] "This interactive specialization view implies that cortical regions might initially be non-specific in their responses but gradually narrow their responses as their functional specialization restricts them to a narrower set of circumstances."[11]

The brain is further limited by its constraint within the body. The brain receives input from receptors on the body (e.g., somatosensory system, visual system, auditory system, etc.). These receptors provide the brain with a source of information. As a result, they manipulate the brain's neural activation patterns, and thus its structure, leading to constraining effects on the construction of representations in the mind. The sensory systems limit the possible information the brain can receive and therefore act as a filter.[11] However, the brain may also interact with the environment through manipulation of the body (e.g., movement, changes in attention, etc.), thus manipulating the environment and the subsequent information received. Pro-activity while exploring the environment leads to altered experiences and consequently altered cognitive development.[11]

While a person may manipulate the environment, the specific environment in which the person develops has highly constraining effects on the possible neural representations exhibited through a restriction of the possible physical and social experiences.[11] For example, if a child is raised without a mother, the child cannot change his/her responses or actions to generate a mother. S/he may only work within the specified constraints of the environment in which s/he is born.

All of the above constraints interact to form cognitive representations in the brain. The main principle is context dependence, as shaping occurs through competition and cooperation.[11] Competition leads to the specialization of developing components which then forms new representations. Cooperation, on the other hand, leads to combinations of existing mental representations that allow existing knowledge to be reused. Construction of representations also depends on the exploration of the environment by the individual. However, the experiences derived from this pro-activity constrain the range of possible adaptations within the mental representations.[11] Such progressive specialization arises from the constraints of the past and current learning environment. To alter representations, the environment demands improvements through small additions to the current mental state. This leads to partial[11] instead of fixed representations that are assumed to occur in adults. Neuroconstructivism argues such end products do not exist. The brain's plasticity leads to ever-changing mental representations through individual proactivity and environmental interactions. Such a viewpoint implies that any current mental representations are the optimal outcome for a specified environment. For example, in developmental disorders like autism, atypical development arises because of adaptations to multiple interacting constraints, the same as normal development. However, the constraints differ and thus result in a different end-product. This view directly contrasts previous theories which assumed that disorders arise from isolated failures of particular functional modules.[11]