Domain-Specific Development and Developmental Disorders

This lecture looked at the difference between Domain-Specific and Domain-General Development and used examples of specific psychological deficits in autism and Williams syndrome and general deficits in Down’s syndrome.

Domain-general development is the view that psychological ability develops generally across different levels (e.g., cognition, language, perception) and they all reach similar levels.

Domain-specific development is the view that psychological ability can develop to different degrees in different areas (e.g., better at language than numeracy). Fodor (1983) talked of different “mental modules” that may be specialized to deal with specific areas of knowledge.

Examples of domains of knowledge which might be processed by specific mental modules:

• Language
• Perception and facial cognition
• Face recognition
• Theory of Mind
• Reading and Spelling
• Number Skills
• Planning and ‘executive’ skills

Autism

Kanner (1943) characterized Autism by:

• serious language problems
• impaired ability to form relationships
• Lack of imaginative play
• repetitive/obsessive routines and interests

[I will add a more detailed section about autism later, for now I just consider implications for development theories. See the Wikipedia entry on autism for more information]

Autism and language

• 50% of autistic children remain mute all their lives
• When speech does develop it has characteristic aspects (Wing, 1976):
• Echolalia (echooing recent utterances)
• Poor generalization to categories (eg, using “cup” for a specific cup and not for all cups)
• Poor control of pitch an intonation
• Idioms and metaphors are not understood
• Poor pragmatics, e.g., not taking account of the listener, staying on one topic all the time

Autism and Theory of Mind
From Baron-Cohen et al (1986)

• Autistic children fail ToM tasks and perform worse than other mentally handicapped children
• Autistic children can understand “mechanical” stories (eg a balloon hits a tree and pops) but not “mentalistic” stories (eg a girl is surprised because her teddy has been moved from where she left it)

From Leslie (1987)

• There is a problem with “metarepresentations”…
• …a knowledge of what other people know, expect, perceive and believe
• This underlies the difficulty in pretend play, social interaction, communication

Autism and “Central Coherence”
Frith (1989) proposed a particular cognitive deficit in autism that she called weak central coherence. Strong central oherence, which is normal, implies being good on context and weaker on details. Autistics have weak central coherence and are poor on context and good on details. An example of this is that autistic children tend to be good at jigsaws (even if upside down) - they are not influenced by the ‘meaning’ of the picture.

Autistic savants
1 in 10 autistics have savant skills (once known as idiot savants), that is, they excel in a particular domain, usually art, music or calculation. Happe (1999) argues that this may be due to weak central coherence; since some autistics are very good at details they can easily learn perfect pitch or draw at a detailed level.

Williams Syndrome

Described by Williams et al (1961)

• 95% of cases have low IQ
• ToM skills are preserved
• Language is delayed but subsequently very good
• Spacial cognition is impaired but face recognition is ok

[I will add a more detailed section about autism later, for now just consider implications for development theories]

Williams syndrome and drawing

• From Bihrle et al (1989) ‘D’ stimulus, WS participants draw the details but miss the global form. The components do not get integrated. The Wikipedia entry on WS explains why this occurs
• In contrast Down syndrome participants draw the global form but miss the details
• Normal people favour the global level but get some of the details
• In WS spatial cognition is disrupted

Williams syndrome and language skills
WS develop good language skills, have a large vocabulary but there is a tendency to use unusual words. Speech can be disassociated and jump from topic to topic.

Comparison

Conclusion

Autism and WS support the belief that aspects of psychological development are domain-specific. However Down syndrome would suggest that psychological ability is developed generally across domains.

Useful links

Summary of Discussion of Williams Syndrome, Autism, and Consciousness