Trends in Cognitive Sciences
Volume 2, Issue 10, 1 October 1998, Pages 389-398
Journal home page for Trends in Cognitive Sciences

Development itself is the key to understanding developmental disorders

https://doi.org/10.1016/S1364-6613(98)01230-3Get rights and content

Abstract

It is a truism that development involves contributions from both genes and environment, but theories differ with respect to the roles they attribute to each, which deeply affects the ways in which developmental disorders are researched. The strict nativist approach to abnormal phenotypes, inspired by adult neuropsychology and evolutionary psychology, seeks to identify impairments to domain-specific cognitive modules and studies the purported juxtaposition of impaired and intact abilities. The neuroconstructivist approach differs in several respects: (i) it seeks more indirect, lower-level causes of abnormality than impaired cognitive modules; (ii)modules are thought to emerge from a developmental process of modularization; (iii) unlike empiricism, neuroconstructivism accepts some form of innately specified starting points, but unlike nativism, these are considered to be initially `domain-relevant', only becoming domain-specific with the process of development and specific environmental interactions; and (iv) different cognitive disorders are considered to lie on a continuum rather than to be truly specific. These alternative theoretical positions are briefly considered as they apply to Specific Language Impairment, and followed by a more detailed case study of a well-defined neurodevelopmental disorder, Williams syndrome. It is argued that development itself plays a crucial role in phenotypical outcomes.

Section snippets

The implications for developmental disorders

The neuroconstructivist modification in perspective crucially influences the way in which atypical development is considered. In this approach, the deletion, reduplication or mispositioning of genes will be expected to subtly change the course of developmental pathways, with stronger effects on some outcomes and weaker effects on others. A totally specific disorder will, ex hypothesis, be extremely unlikely, thereby changing the focus of research in pathology. Rather than solely aiming to

Are some developmental disorders truly specific?

Despite the arguments in the previous section, some developmental disorders (e.g. autism18, 19, Asperger syndrome[20], dyslexia[21], Turner's syndrome[22], Specific Language Impairment[14]) appear at first sight to involve very specific deficits at the cognitive level. Autism, for example, is argued to be the result of impairment of the domain-specific mechanism of metarepresentation, dedicated solely to the processing of social stimuli10, 19—a deficit in the so-called `theory-of-mind' module.

Conclusions

One of the major problems with very specific accounts of developmental disorders of higher-level cognition is that so far no gene (or set of genes) has been identified that is expressed solely in a specific region of neocortex (see Ref. [30]for discussion). Yet, such theories claim that neocortex is pre-specified for functions such as theory of mind or language and that this is why they can dissociate in adulthood. This is the basis for most brain imaging studies. Some authors go as far as

Outstanding questions

  • Some argue that evolution has provided the human cortex with increasingly detailed pre-specification prior to ontogenetic development. To what extent can the ontogenetic data be accounted for in terms of evolution selecting for less specific factors, such as increased neocortical plasticity and a greater range of learning mechanisms, to ensure adaptive outcomes rather than prior knowledge? Is it more useful to entertain the possibility that the highest level of evolution is to pre-specify

Acknowledgements

I should like to thank Mike Anderson, Susan Carey, Mark Johnson and Steven Rose, as well as the anonymous reviewers, for comments on an earlier version of this paper.

References (62)

  • Elman, J.L. et al. (1996) Rethinking Innateness: A Connectionist Perspective on Development, MIT...
  • S.R Quartz et al.

    A neural basis of cognitive development: a constructivist manifesto

    Behav. Brain Sci.

    (1997)
  • Frith, U. and Happé, F. Why specific developmental disorders are not specific: on-line and developmental effects in...
  • S Baron-Cohen

    How to build a baby that can read minds: cognitive mechanisms in mindreading

    Cahiers de Psychol. Cognit.

    (1994)
  • J Tooby et al.

    On the universality of human nature and the uniqueness of the individual: the role of genetics and adaptation

    J. Personal.

    (1990)
  • A Karmiloff-Smith

    Annotation: the extraordinary cognitive journey from foetus through infancy

    J. Child Psychol. Child Psychiatry

    (1995)
  • Bishop, D.V.M. (1997) Uncommon Understanding: Development and Disorders of Language Comprehension in Children,...
  • A Karmiloff-Smith

    Crucial differences between developmental cognitive neuroscience and adult neuropsychology

    Dev. Neuropsychol.

    (1997)
  • J Mancini

    Face recognition in children with early right or left brain damage

    Dev. Med. Child Neurol.

    (1994)
  • Frith, U. (1989) Autism: Explaining the Enigma, Blackwell...
  • A.M Leslie

    Pretence, autism and the theory-of-mind module

    Curr. Dir. Psychol. Sci.

    (1992)
  • Frith, U., ed. (1991) Autism and Asperger Syndrome, Cambridge University...
  • C Frith et al.

    A biological marker for dyslexia

    Nature

    (1996)
  • D.H Skuse

    Evidence from Turner's syndrome of an imprinted X-linked locus affecting cognitive function

    Nature

    (1997)
  • F.G.E Happé

    Studying weak central coherence at low levels: children with autism do not succumb to visual illusions (a research note)

    J. Child Psychol. Psychiatry

    (1996)
  • M Gopnik

    Feature-blind grammar and dysphasia

    Nature

    (1990)
  • C.M Temple

    Cognitive neuropsychology and its application to children

    J. Child Psychol. Psychiatry

    (1997)
  • P Tallal

    Language comprehension in language-learning impaired children improved with acoustically modified speech

    Science

    (1996)
  • A.J Fawcett et al.

    Impaired performance of children with dyslexia on a range of cerebellar tasks

    Ann. Dyslexia

    (1996)
  • B Pennington

    Using genetics to dissect cognition

    Am. J. Hum. Genet.

    (1997)
  • Gerhart, J. and Kirschner, M. (1997) Cells, Embryos and Evolution, Blackwell...
  • Cited by (0)

    View full text