Implications of the idea of neurodiversity for understanding the origins of developmental disorders.

Neurodiversity, a term initially used mostly by civil and human rights movements since the 1990s, refers to the notion that cognitive as well as emotional properties characteristic of developmental disorders such as autism spectrum disorders (ASD) are not necessarily deficits, but fall within normal behavioural variations exhibited by humans. The purpose of the present article is to examine the relevance of this notion to scientific research on ASD. On the assumption that one crucial survival advantage of intelligent activity is vigilance toward dangers in the external world, and such vigilance must work in the social domain as well as in the non-social domain, the author argues that the pattern of operation of an individual person's mind can be categorized according to the domain toward which that individual is more oriented. Individuals with ASD, overall, do not rely upon their social relationships but rather are predisposed to process perceived non-social objects in more depth, which manifests itself as hyper-sensation and hyper-attention to detail. It can be assumed that underconnectivity among cortical areas and subcortical areas underlies such mental operation neurologically. One of the main predictions based on this assumption is that all facets of psychological function are susceptible to disruption in ASD. Indeed, it has traditionally been thought that there are such general deficits in this disorder. However, contrary to the prevalent belief that people with ASD lack empathy, in fact people with ASD are capable of empathizing with the minds of others if those others are people with ASD. Thus, the neurological underconnectivity in ASD certainly leads some processing of information in the mind to work with less coordination, but has in fact contributed to providing Homo sapiens with behavioural variants. Finally, the clinical implications of the advantages of viewing ASD as a variation in neurodiversity are discussed.