Weak Central Weak Central CoherenceCoherence

A Comprehensive Theory of A Comprehensive Theory of AutismAutism

Autistic savant artistsAutistic savant artists

Frith (2003)Frith (2003)

The need to explain non-social features of The need to explain non-social features of autismautism

The need to explain savant abilitiesThe need to explain savant abilities The need to explain an apparent lack of The need to explain an apparent lack of

common sensecommon sense The need to explain anecdotal reports of The need to explain anecdotal reports of

heightened perceptual abilitiesheightened perceptual abilities The need to explain an uneven intellectual The need to explain an uneven intellectual

profileprofile

Block Design Test (Shah & Frith, Block Design Test (Shah & Frith, 1993)1993)

Individuals with autism Individuals with autism were significantly faster were significantly faster than matched controls than matched controls

Pre-segmentation Pre-segmentation helped controls but not helped controls but not individuals with autismindividuals with autism

Embedded Figures Test Embedded Figures Test (Shah & Frith, 1983)(Shah & Frith, 1983)

Individuals with autism Individuals with autism were significantly faster were significantly faster at locating the hidden at locating the hidden figure than matched figure than matched controls.controls.

Pring et al (1995): Pring et al (1995): Individuals with autism Individuals with autism were as fast at solving a were as fast at solving a jigsaw upside-down as jigsaw upside-down as right-way-upright-way-up

Frith & Snowling (1986)Frith & Snowling (1986)

Ambiguous homographs:Ambiguous homographs: ““She was doing some sewing when she She was doing some sewing when she

noticed a tear in her dress”noticed a tear in her dress” ““She was watching a sad movie and then a She was watching a sad movie and then a

tear appeared in her eye”tear appeared in her eye”

Superiority in visual searchSuperiority in visual search

O’Riordan et al (2001)

The Navon taskThe Navon taskMottron et al (1993)Mottron et al (1993)

ssssssssss

ssssssssss

s s s s s s s

Narrowing of attentional spreadNarrowing of attentional spreadMann & Walker (2003)Mann & Walker (2003)

Boundary Boundary ExtensionExtension

Intraub (1990)Intraub (1990)

Chapman et al, 2005

ResultsResults

Clear boundary extension, with a mean Clear boundary extension, with a mean value of 12.51% (i.e. as if 12.5% further value of 12.51% (i.e. as if 12.5% further away): , away): , tt(35) = 10.78, (35) = 10.78, pp < .001, < .001, dd = 1.80. = 1.80.

The degree of boundary extension was The degree of boundary extension was virtually identical between those with and virtually identical between those with and without autismwithout autism

Reduced susceptibility to Reduced susceptibility to illusionsillusions

Happe (1996)Happe (1996) Individuals with autism Individuals with autism

were less susceptible to were less susceptible to illusions than matched illusions than matched controls controls

But….But…. Failed Replication by Failed Replication by

Ropar & Mitchell (2001)Ropar & Mitchell (2001)

Thouless (1931)Thouless (1931)Phenomenal regression to the real object:Phenomenal regression to the real object:

a demonstration of shape constancya demonstration of shape constancy

Ropar and Mitchell (2002)Ropar and Mitchell (2002)

slanted

Perspective

slanted

Knowledge

not slanted

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Stimulus Shape

Projected ShapeViewing Condition

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Ellipse

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Knowledge