the weak coherence account: detail-focused cognitive style in
TRANSCRIPT
The Weak Coherence Account: Detail-focused Cognitive Stylein Autism Spectrum Disorders
Francesca Happe1,3
and Uta Frith2
‘‘Weak central coherence’’ refers to the detail-focused processing style proposed tocharacterise autism spectrum disorders (ASD). The original suggestion of a core deficit in
central processing resulting in failure to extract global form/meaning, has been challenged inthree ways. First, it may represent an outcome of superiority in local processing. Second, itmay be a processing bias, rather than deficit. Third, weak coherence may occur alongside,
rather than explain, deficits in social cognition. A review of over 50 empirical studies ofcoherence suggests robust findings of local bias in ASD, with mixed findings regarding weakglobal processing. Local bias appears not to be a mere side-effect of executive dysfunction, andmay be independent of theory of mind deficits. Possible computational and neural models are
discussed.
KEY WORDS: Autism spectrum disorders; central coherence; cognitive style; individual differences;
local–global processing.
Some individuals with autism spectrum disorders(ASD) can name the pitch of the ‘‘pop’’ as a corkcomes out of a bottle, or identify dozens of brands ofvacuum cleaner from their sound alone. Others canspot a misaligned book in a bookcase in seconds, ormimic foreign speech distinctions not usually notice-able to non-native speakers. These exceptional per-ceptual abilities may be maladaptive in so far as theymay lead to distress at small changes in the environ-ment. Kanner’s original description of autism high-lighted this attention to detail and ‘inability toexperience wholes without full attention to theconstituent parts’ as one factor in the characteristic
insistence on sameness: ‘A situation, a performance, asentence is not regarded as complete if it is not madeup of exactly the same elements that were present atthe time the child was first confronted with it. If theslightest ingredient is altered or removed, the totalsituation is no longer the same and therefore is notaccepted as such...’ (Kanner, 1943, p. 246). Indeed, a‘persistent preoccupation with parts of objects’ is oneof the diagnostic criteria for autistic disorder incurrent practice (DSM-IV, APA, 1994).
Understanding perceptual processes in ASDmay involve explaining both disordered and superiorprocessing. One cognitive theory that has specificallysought to address both deficits and assets in ASD isthe ‘‘weak coherence’’ account. Frith (1989) drewattention to the tendency for typically developingchildren and adults to process incoming informationfor meaning and gestalt (global) form, often at theexpense of attention to or memory for details andsurface structure. This tendency, referred to byBartlett (1932) as ‘‘drive for meaning’’, was termed
1 Social, Genetic and Developmental Psychiatry Centre, Institute
of Psychiatry, King’s College London, London, UK.2 Institute of Cognitive Neuroscience, University College, London,
UK.3 Correspondence should be addressed to: Social, Genetic and
Developmental Psychiatry Centre, Institute of Psychiatry, King’s
College London, De Crespigny Park, Denmark Hill, P.O. Box
P080, SE5 8AF, London, UK. e-mail: [email protected]
� 2006 Springer ScienceþBusiness Media, Inc.
Journal of Autism and Developmental Disorders (� 2006)
DOI 10.1007/s10803-005-0039-0
‘‘central coherence’’ by Frith. Individuals with ASDwere hypothesised to show ‘‘weak central coherence’’;a processing bias for featural and local information,and relative failure to extract gist or ‘‘see the bigpicture’’ in everyday life. This processing bias wasevident in early work on verbal memory, showingrelatively little benefit from meaning (Hermelin &O’Connor, 1967), and exact rather than correctedrepetition (Aurnhammer-Frith, 1969). In early workusing visuo-spatial tasks, ASD groups showed supe-riority at disembedding (Shah & Frith, 1983), greaterreliance on adjacent elements in pattern extraction(Frith, 1970), and a reduced inversion effect in faceprocessing (Langdell, 1978).
Interest in the coherence account of ASD hasgrown rapidly since the early work by Frith (1989)and Happe (1999; Frith & Happe, 1994), with morethan 60 publications relating to this topic publishedsince 1999, a fourfold increase on the previous 10-year period. In that time, and in response to empiricalfindings, the coherence account has been modifiedfrom Frith’s original conception in three importantways. First, the original suggestion of a core deficit incentral processing, manifest in failure to extractglobal form and meaning, has changed from aprimary problem to a more secondary out-come—with greater emphasis on possible superiorityin local or detail-focused processing. Second, the ideaof a core deficit has given way to the suggestion of aprocessing bias or cognitive style, which can beovercome in tasks with explicit demands for globalprocessing. Last, the explanatory remit of the accounthas changed, with a recognition that weak coherencemay be one aspect of cognition in ASD alongside,rather than causing/explaining, deficits in socialcognition (e.g. ‘‘theory of mind’’; Frith, 1989, revised2003).
Along with increased research interest, thenotion of weak coherence or detail-focused process-ing style, has been received with enthusiasm andimmediate recognition by the ASD community(affected individuals and their families). Autobio-graphical accounts of autism often describe frag-mented perception (Gerland, 1997). Weak coherenceis seen as addressing aspects of ASD that some otheraccounts have neglected, such as areas of talent,super-acute perception, and lack of generalisation.For example, perceptual abnormalities such as hyper-sensitivity, clinically/anecdotally reported but littlestudied in research to date, may relate to context-freeprocessing as expectations and context-based inter-pretation are known to modulate experience of
sensory stimuli in ‘‘neurotypicals’’ (people withoutASD). Just as there is a higher than usual occurrenceof perfect pitch in ASD (Miller, 1999), so absolute,rather than relative, coding of other sensory stimulimay underlie some aspects of perceptual discomfortor fascination. Problems with generalisation of skillswould follow from weak coherence, if experiences arecoded in terms of details. If people with ASDremember each exemplar rather than extractingprototypes (Klinger & Dawson, 2001), this wouldrender recognition of situations that are ‘‘alike’’problematic: only if a situation shares the keydetail(s) with a previous experience, will generalisa-tion of skills occur (Plaisted, 2001; Rincover &Koegel, 1975).
OVERVIEW OF RESEARCH
Table I summarises published experimentalgroup studies in which weak coherence in ASD isaddressed, and those directly relevant studiesdescribed below. A number of studies, both withinand beyond those explicitly addressing coherence, aredirectly relevant to perceptual processing in ASD.Relevant to perception in the auditory modality, aredemonstrations of stable memory for exact pitches(Bonnel et al., 2003; Heaton, Hermelin, & Pring,1998), enhanced local processing (with intact globalprocessing) of musical stimuli (Heaton, 2003;Mottron, Peretz, & Menard, 2000), reduced interfer-ence from melodic structure (combining pitch andtiming effects) in music processing (Foxton et al.,2003), and a reduced McGurk effect (i.e. lessinfluence from visual to auditory speech perception;DeGelder, Vroomen, & Van der Heide, 1991).
Relevant to perception in the visual modality,individuals with ASD show raised thresholds forperceiving coherent motion (Bertone, Mottron,Jelenic, & Faubert, 2003; Milne et al., 2002; Spenceret al., 2000), and reduced susceptibility to visuallyinduced motion (Gepner, Mestre, Masson, & Scho-nen, 1995; Gepner & Mestre, 2002). Superior visualsearch (Plaisted, O’Riordan, & Baron-Cohen, 1998a;O’Riordan, Plaisted, Driver, & Baron-Cohen, 2001),and superior discrimination learning of highlyconfusable patterns (Plaisted, O’Riordan, & Baron-Cohen, 1998b), have also been reported. Activeprocesses of visual grouping may be affected, shownin reduced gestalt grouping (Brosnan, Scott, Fox, &Pye, 2004), reduced susceptibility to visual illusions(Happe, 1996; but see, Ropar & Mitchell, 1999,
Happe and Frith
Table
I.Published
GroupStudiesAssessingCentralCoherence
inAutism
Spectrum
Disorders
Reference
Participants
(groupmeans)
Tasks
Main
findings
Visuo-spatial
EFT
ShahandFrith
(1983)
20ASD
CA
13,MA
NV
9.6
CEFT
ASD
groupaccuracy
>MH,TD
20TD
MA-m
atched
Qualitativeevidence
ofmore
immediate
success
20MH
CA
andMA
match
BrianandBryson(1996)
16ASD
CA
20,Ravensraw
39,
Disem
bedding:adapted(m
eaningful)CEFT
item
splusabstract
andfragmenteditem
s
Nogroupdifferencesofgroup�
conditioninteractions
34%le,PPVTst
score
77,raw
120
Recognition:asaboveplusdistractoritem
s
RTto
disem
bedded
Meaningful>
Abstract>Fragmented
inallgroups
15TD
CA
12,Ravensscore
39,55%ile
Recognitionaccuracy
Meaningful>
Abstract=
Fragmented(atchance)in
allgroups
16TD
CA
12,PPVTst
score
103,
raw
score
119
JolliffeandBaron-C
ohen
(1997)
17HFA
CA
31,FIQ
105
EFT
HFA
andAsperger
groupsfaster
thanTD
onEFT.
17ASCA
28,FIQ
107
Modified
Rey
drawingtask
Nogroupdifferencesondrawingtask
17TD
CA
andFIQ
matched
RoparandMitchell(2001)
19autism
CA
14,VMA
7EFT,Block
design
Autism
>MH,TD
onEFTandBlock
Design(A
S=
TD
11-year-old
group)
11ASCA
12,VMA
10
20MH
CA
13,VMA
7
37TD
CA
8&
11
Jarrold
etal.(2000)
17ASD
CA
10,VMA
8CEFT,DASBD
(+Belieftasks)
InASD
andTD
children,EFTandBD
negativelycorre-
latedwithToM
scoresonce
VMA
andCA
partialled
out
24TD
CA
5PreschoolEFT,DASBD
(+Belieftasks)
EFTnegativelycorrelatedwithEyes
Testscore
60TAdultsCA
18–25
EFTandEyes
Task
Morganet
al.(2003)
21ASD
CA
4,VMA
33months,
Leiter(N
VIQ
)95
PreschoolEFT
ASD
faster
thancontrolsonEFT(accuracy
ns)
21TD/M
HCA
andnVIQ
matched
PatternConstruction(D
AS)(+
joint
attention,pretendplayratings)
ASD>ControlsonPatternConstruction
Correlationscoherence�
jointattention,pretendplayns
Block
Design
ShahandFrith
(1993)
10HighIQ
ASD
PIQ
97
Wechsler
Block
Design
7/10HiIQ
(scaledscores13–19)and6/10lo
IQASD
(ss
9–15)BD
personalpeaksubtest
10Low
IQ(<
85)PIQ
71
Experim
entalUn/SegmentedBlock
Design
task
ASD
groupsderiveless
benefit(tim
etaken)from
preseg-
mentationofdesignto
becopied:
17older
TD
CA
16,PIQ
100
HiIQ
ASD
faster
thanolder
TD
onwhole
designsonly
16younger
TD
CA
11matched
low
IQASD
WISC
nV
raw
score,PIQ
105
LoIQ
ASD
faster
thanyounger
TD&
MH
onwhole
de-
signsonly
12MH
CA
17,PIQ
m76
Happe(1994)
51ASD
CA
15,FIQ
64(splitbyToM)
Wechsler
Block
Designin
fullWISC
or
WAIS
Block
Design>
meanPerform
ance
subtestscore
for85%,
regardless
ofToM
perform
ance
Weak Coherence
Table
I.Continued
Reference
Participants
(groupmeans)
Tasks
Main
findings
Pring,Hermelin,&
Heavey
(1995)
18ASD
CA
26,RavensMA
12
Block
designtask;meaningfulscenes,and
Wechsler-likedesigns
ArtisticallytalentedTD
faster
thanASD
onmeaningful
scenes.
18TD
MA
matched
ArtisticallytalentedTD
andallASD
(regardless
ofartistic
talent)
faster
thannonartisticTD
Both
grouped
byartisticability
Hierarchicalfigures
Ozonoff,Strayer,
McM
ahon,&
Filloux
(1994)
14ASD,CA
12,FIQ
100
NavonHierarchicalFigurestask;largeletter
composedofsm
aller
sameordifferent
letter
(selectiveattention)
Nogroupdifferences;allgroupsshowed
globaladvantage
andinterference
14TD
CA
andIQ
matched
14TourettesyndromeCA
and
IQmatched
Mottronet
al.(1999)
11HFA
CA
15,RavensIQ
110
NavonHierarchicalFigures(divided
attention)
HFA,butnotTD,groupshow
aglobaladvantage
11TD
CA
andIQ
matched
Palm
ermentalsynthesistask
Nogroupdifferencesin
effectofgoodnessofPalm
er
figures
Plaistedet
al.(1999)
17ASD
CA
10,raven’sscore
33
NavonHierarchicalFiguresin
Divided
and
Selectiveattentionconditions
Nogroupdifferencesin
selectiveattentioncondition
17TD
CA
andRaven’sraw
score
matched
ASD
show
noglobaladvantagein
divided
attentioncon-
dition(TD
domakefewer
errors
fortargetsatglobalthan
locallevel)
Rinehart
etal.(2000)
12HFA
CA
10,FIQ
94
NavonHierarchical(numbers)
Figures(selec-
tiveattention)
Allgroupsshowed
expectedglobaladvantageandinter-
ference
12ASCA
12,FIQ
104
HFA,butnotASgroup,showed
more
localinterference
thanTD
12+
12TD
CA
andIQ
matched
Rinehart
etal.(2001)
12HFA
CA
10,FIQ
94
NavonHierarchical(numbers)
Figures
(divided
attention)
HFA
RTto
globallevel
targetsslowed
when
previous
target
atlocallevel,comparedwithTD
group(deficit
movingfrom
localto
globalprocessing)
12ASCA
12,FIQ
104
Nosuch
groupdifference
forASgroup
12+
12TD
CA
andIQ
matched
Mottronet
al.(2003)
12HFA
CA
16,IQ
105–110
Hierarchicalfigures
Nogpdifference
(butalsonoglobaladvantagein
TD
group)
10–12TD
matched
onCA
&IQ
Fragmentedletter
recognition
Nogpdifference
(butalsonomain
effectofcondition)
Silhouette
identification
Nogpdifference
(butalsonomain
effectofcondition)
Long-short-rangegrouping
Nogpdifference
Disem
bedding
ASD>
TD,em
beddingeff
ects
TD
grouponly
VisualIllusion
Happe(1996)
25ASD
CA
13,VMA
7Judgeillusionsin
2D
and3D
form
s(verbal
response
toillusionsoncards)
ASD
succumbto
fewer
illusionsthanMH
andTD
21TD
CA
7ASD
showless
benefitfrom
3D
disem
beddingthandoMH
andTD
26MH
CA
andVMA
matched
ASD=MH,TD
number
correctfor3D
illusions
Happe and Frith
RoparandMitchell(1999)
23autism
CA
13,VMA
7Adjust
partsofcomputerisedillusions
Participants
inallgroupsstrongly
susceptible
toillusions
inboth
form
ats,nosignificantgroupdifferences
13ASCA
14,VMA
14
Verbalresponse
toillusionsoncards
17MH
CA
10,VMA
6
41TD
CA
8&
11,15adults
RoparandMitchell(2001)
19autism
CA
14,VMA
7Adjust
partsofcomputerisedillusions
Nogroupdifferencesin
susceptibilityto
illusions
11ASCA
12,VMA
10
Rey
Figure
drawing,BD,EFT,EFT
Rey
figure
gavenoevidence
ofgroupdifferencesin
global
approach.Perform
ance
onillusionsnotrelatedto
perfor-
mance
onvisuo-spatialtasks
20MH
CA
13,VMA
7
37TD
CA
8&
11
Drawing
Mottronet
al.(1999)
10HFA
CA
19,PIQ
112
Copyingdrawings(realobjects,non-objects,
possible
andim
possible
figures)
HFA
groupdraw
more
localfeaturesatstart
ofcopyand
are
less
slowed
byim
possibilityoffigure,comparedwith
controls
11TD
CA
andPIQ
matched
Booth
etal.(2003)
30ASD
CA
11,FIQ
100
Drawingfrom
anexample
ASD
groupshowed
more
detail-focuseddrawingstyle
(25%
start
withdetail,draw
fragments,33%
violate
con-
figuration)vs.TD
andADHD
31TD
CA
andFIQ
matched
30ADHD
CA
andFIQ
matched
Motioncoherence
Spenceret
al.(2000)
23ASD
(noCA
orIQ
details)
Motioncoherence
threshold
task
ASD
raised
motion,butnotform
,coherence
thresholds
relatives
toTD
50VMA
matched
(7–11)
Form
coherence
threshold
task
19T
adults
Milneet
al.(2002)
25ASD
CA
12,Ravensraw
score
41
Motioncoherence
threshold
task
ASD
raised
motioncoherence
threshold
vs.TD
22TD
CA
andRavensmatched
Bertoneet
al.(2003)
12HFA
CA
12,IQ
101
Sensitivityforfirst-andsecond-order
motion
HFA=TD
onfirst-order
(luminance-defined)motion
12TD
CA
13
HFA
worsethanTD
atdetectingsecond-order
(texture-
defined)motion
Pellicanoet
al.(2005)
20ASD
CA
10,Ravensraw
score
40
Flicker
contrast
sensitivity
Nogroupdifference
20TD
CA
andRavensmatched
Globaldotmotion(G
DM)task
ASD
higher
thresholdsthanTD
CEFT
ASD
faster
thanTD.Inverse
relationCEFT
RTxGDM
thresholdsin
ASD
only
Faces(selected
studies)
Hobson,Ouston,andLee
(1988)
17ASD
CA
19,BPVSraw
score
65,Ravens
raw
score
36
Uprightface
identity/emotionmatching,blank-
mouth/forehead
ASD
emotionmatchingdeclined
withfewer
cues,MH
less
soASD>MH
matchinginvertedfaces
17MH
CA
19,BPVS66,Raven’s22
Invertedface
identity/emotionmatching
Teunisse
anddeGelder
(2003)
17HFA
CA
19,VIQ
90
Inversioneff
ecttask
Allgroupsworseatrecognisinginvertedthanuprightfaces
24TD
CA
9–10
Composite
effecttask
Non-aligned
compositesrecognised
faster
thanwholes
(composite
effect)
inTadults,TD
(p<
.06),notin
HFA
(suggestingreducedwholistic
processing)
16/24TadultsCA
23
Weak Coherence
Table
I.Continued
Reference
Participants
(groupmeans)
Tasks
Main
findings
Deruelle
etal.(2004)
11ASD
CA
9,VMA
7Face
recognition(m
atchingtasks)
ASD<TD
onem
otion,gener,gaze
direction.lipreading
11TD
CA
6Matchinghigh-pass
filter
(local)orlow-pass
filter
(global)faces
ASD=TD
onidentity
recognition
11TD
CA
9ASD
betterperform
ance
withhigh(local)vs.low
(global)
spatialfrequency
stim
uli.TD
show
opposite
pattern
Lopez
etal.(2004)
17HFA
CA
13,FIQ
87
Face
matching,whole
vs.part
with/outcueing
HFA
show
‘whole
face
advantage’
only
when
cued,TD
show
whole
face
advantagecued
anduncued
17TD
CA
13,FIQ
97
Rouse
etal.(2004)
11ASD
CA
10,VMA
6,RavensMA
9Thatcher
illusion(totest
perceptionofsecond-
order
relations)
ASD=MH
inshowingThatcher
illusion(notice
inverted
eyes
andmouth
within
uprightface>
invertedface).TD
ceilingeff
ects.
15MH
CA
&VMA
match
usingface
photos,house
photos,Mooney
faces
Trendforstronger
inversioneff
ectin
TD
vs.ASD,
ASD=MH
15TD
CA
match
Various
Burack
(1994)
12ASD
CA
20,FIQ
50,MA
8Forced-choiceRTtask,with/outwindow
aroundtarget,with/outdistractorstim
uli
Withoutdistractors,ASD
benefitmore
thanother
groups
from
window
62MH
CA
13,FIQ
60,MA
8
ASD
more
adversely
affectedthanother
groupsby
distractors
(nearorfarfrom
target)when
window
present
34TD
CA
8,FIQ
104,MA
8
Gepner
etal.(1995)
5ASD
CA
6(noIQ
inform
ation)
Posturalreactivityto
visuallyperceived
motion
ASD
more
unstableposturally,butless
affectedbyvisually
perceived
environmentalmotion
12TD
CA
6
Jarrold
andRussell(1997)
22ASD
CA
12,VMA
7Dotcountingin
canonicalvs.distributed
arrays
ASD<TD
benefitfrom
canonicalarrangem
ent(M
Hnot
differentfrom
either
group)
22TD
VMA
match
45
%ofASD
Ss‘globalcounters’,vs.68%
MH
(sig),
MH<
TD
22MH
CA
andVMA
match
Plaistedet
al.(1998a)
8ASD
CA
9,VMA
7,Block
DesignMA
11
Visualsearchtask
(feature
vs.conjunctive
conditions;5,15or25item
displays)
ASD=TD
onfeature
search
8TD
CA
8,VMA
7,Block
DesignMA
7
ASD
faster
thanTD
onconjunctivesearchcondition,and
less
slowed
byincreasingdisplaysize
Plaistedet
al.(1998b)
8ASD
CA
29,BD
scale
score
13
Perceptuallearningtask
Noperceptuallearningeff
ectin
ASD
10TD
CA
andBD
matched
ASD>TD
discrim
inationofnovel
stim
uli
JolliffeandBaron-C
ohen
(2001)
17HFA
CA
31,FIQ
105
Object
Integrationtest
ASD<TD
integratingobjectsto
makecoherentscene
17Asperger
CA
28,FIQ
107
Scenic
test
ASD<TD
spottingincongruentobjectsandidentifying
scene
17TD
CA
andFIQ
matched
JolliffeandBaron-C
ohen
(2001)
17HFA
CA
31,FIQ
105
Modified
Hooper
VisualOrganisationtest
HFA
<Asperger
<TD
integratingfragmentsto
identify
whole
object
(nsatidentifyingobject
from
single
part)
17ASCA
28,FIQ
107
17TD
CA
andFIQ
matched
Happe and Frith
Klinger
andDawson(2001)12ASD
CA
14,VIQ
57,VMA
7Rule-basedcategory
learning
Allgroupsextract
rulesto
learn
new
category
(nogroup
effect)
12DSCA
14,VIQ
/MA
matched
Prototypetask
Only
TD
groupdevelopaprototype(TD>
ASD=
DS)
12TD
CA
7,VMA
matched
O’R
iordanet
al.(2001)
12ASD
CA
8,Ravensscore
26
Visualsearchtask
(feature
vs.conjunctive
conditions;5,15,25item
)
ASD=
TD
onfeature
search
12TD
CA
8,Ravensscore
26
ASD
faster
thanTD
onconjunctivesearchcondition,and
less
slowed
byincreasingdisplaysize
Gepner
andMestre(2002)
3autism
CA
9,PEPMA
2–4
Posturalreactivityto
fast
visualmotion
Autism
groupmore
posturallystable
thanTD,ASchil-
dren
3ASCA
7,FIQ
85–115
Autism
grouphyporeactiveto
visualmotionvs.TD
group
9TD
CA
8
ASchildrenless
posturallystable,atleast
asreactiveto
visualmotionasTD
Lopez
andLeekam
(2003)
15HFA
CA
14,FIQ
87
Visualpriming(scene
–object)
Nogroupdifference,both
groupsprimed
bycontext
16TD
CA
14,FIQ
99
Mem
ory
forun/relatedpictures
Nosignificantgroupdifference
inbenefitfrom
related
pictures
MannandWalker
(2003)
13ASD
CA
10,Ravensscore
26,BPVS
score
59
RTto
judgewhichlineofacrosshairlongest,
presentinglongandsm
allcrosshairs
Nogroupdifference
bycrosshairsize
forfirststim
ulus
15MH
CA,Ravens&
BPVSscore
matched
ASD
less
accurate
andslower
judginglargecrosshairafter
asm
allcrosshair(vs.largeafter
large)
15TD
CA
5,Ravens&
BPVSscore
matched
Nogroupdifferencesjudgingsm
allcrosshairafter
large
(vs.sm
allafter
small)
Plaistedet
al.(2003)a
9HFA
CA
10,Ravensscore
30
Biconditionalconfigurationdiscrim
ination
HFA>
TD
onfeature
task
(%correct)
9TD
CA
andRavensmatched
Feature
vs.configurationpatterning
HFA=
TD
onbiconditionaltask
12HFA
CA
9,Ravensscore
30
Feature>biconditionalforHFA
only
12TD
CA
andRavensmatched
HFA
feature>
configurationtrials(%
correct)
TD
configuration>
feature
trials
Brosnanet
al.(2004)
25ASD
CA
11,VMA
5Grouping,oddoneoutandim
possibility
judgem
enttaskstestingsimilarity,proxim
ity,
closure
ASD<MH
inuse
ofgestaltprinciplesfortheperceptual
judgmenttasks(notin
adrawingtask)
25MH
CA
10,VMA
5
Auditory
Pitch
andmusic
Heatonet
al.(1998)
10ASD
CA
9,MA
8Mem
ory
forexact
pitches
ASD>
TD
number
pitches
correctlyrecalled
10TD
CA
8(M
Amatched)
Mottronet
al.(2000)
13ASD
CA
17,PIQ
107
Same-differentjudgem
entofmelodies(localor
globallyaltered)
ASD>
TD
atdetectionofchangein
non-transposed,
contour-preserved
melodies,reflectinglocalbiasbutnot
globaldeficit
13TD
CA
andPIQ
matched
Bonnel
etal.(2003)
12HFA
CA
18,FIQ
108
Discrim
inationandcategorisationofpure
tones
ASD>
TD
atboth
tasks
12TD
CA
andIQ
matched
Foxtonet
al.(2003)
13ASD
CA
18,FIQ
88
Matchpitch
directionchanges
between2and
5-note
auditory
sequences,localorglobally
altered
(same/differentjudgment)
TD
more
impaired
thanASD
byalterationsto
localfea-
tures(pitch
andtiming),interpretedasinterference
overall
gestalt.Absence
ofinterference
from
auditory
coherent
whole
inASD.
15TD
CA
andIQ
matched
Weak Coherence
Table
I.Continued
Reference
Participants
(groupmeans)
Tasks
Main
findings
Heaton(2003)
14HFA
CA
11,Ravens108,VIQ
92
Pitch
mem
ory
andlabelling
HFA>TD
atpitch
mem
ory
andlabelling
28TD
CA
&Ravens/VIQ
match
Disem
beddingun/labelledtones
from
chords
HFA>TD
ondisem
beddingtonefrom
chord
only
when
pre-exposedto
labelledindividualtones
Plaistedet
al.(2003)a
8HFA/A
SCA
13–28,m18
Auditory
filteringtask
Width
ofauditory
filtersabnorm
allybroadin
ASD
vs.
published
TD
data
Verbal
Homographreading
Frith
andSnowling(1983)
8autism
CA
9–17,RA
8–10yrs
Homographreading
Autism
readfewer
homographscorrectlyvs.TD
and
Dyslexia
10TD
CA
9–10,RA
matched
Stroop
Allgroupsshowed
expectedStroopinterference
10Dyslexia
CA
10–12,readingagematched
Gaptests(supply
orchoose
word
tofillgapin
readstory)
Autism
mademore
errors
onboth
GapteststhanTD
or
Dyslexia
groups
SnowlingandFrith
(1986)
16autism
CA
17,RA
10,VMA
6/10
Homographreadingwithpriortraining
Higher
abilityASD
notdifferentfrom
TD
orMH
on
number
ofcorrectlypronouncedhomographsoronGap
tests;low
abilityASD
andMH
groups<
TD
15TD
CA
10,RA
9,VMA
6/10
Gaptests(choose
word
tofillgapin
readstory;
spotanomalousword)
9MH
CA
15,RA
9,VMA
5/9
Happe(1994)
16ASD
CA
17,VIQ
80(divided
byToM
perform
ance)
Homographreading
ASD,regardless
ofToM,failto
use
precedingsentence
contextcomparedwithTD;contextxgroupinteraction
13TD
CA
8
JolliffeandBaron-C
ohen
(1999)
17HFA
CA
31,FIQ
105
Homographreading
ASD<TD
accurate
rare
pronunciations(before
orafter
context)
17ASCA
28,FIQ
107
Bridginginference
task
HFA<Asperger<
TD
atchoosingbridgingcoherentsen-
tence
17TD
CA
andFIQ
matched
Ambiguoussentencestest
HFA<Asperger<
TD
atrecognisingrare
context-depen-
dentsentence
meanings
Lopez
andLeekam
(2003)
15HFA
CA
14,FIQ
87
Homographreading
HFA<
TD
usingcontextto
determinerare
pronunciation.
16TD
CA
14,FIQ
99
Sem
anticprimingtask
Nogroupdifference,both
groupsprimed
bycontextword
Mem
ory
forun/relatedwords
Nogroupdifference
overall;forsubsetof(anim
al)words
ASD
benefitless
thanTD
from
related(vs.unrelated)
word
lists
Various
Beversdorf
etal.(1998)
10HFA
CA
31,FIQ
110
Recalltests;word
listsvaryingin
semantic/
syntactic
order;stories
withsentencesin/not
inlogicalorder
(alsoem
otionandtheory
of
mindconditions)
Nogroupdifferencesin
recallofcoherentvs.incoherent
word
listsorstories.(R
ecallfacilitatedbyem
otionalcon-
tentin
T>HFA)
13TCA
31,FIQ
117
Beversdorf
etal.(2000)
8HFA
CA
32,FIQ
111
Falsemem
ory
test
HFA>T
discrim
inatingfalsemem
ory
item
sfrom
true
item
s(suggestingless
integration/use
ofcontext)
16TCA
31,FIQ
113
Happe and Frith
2001), and reduced benefit from canonical pattern indot counting (Jarrold & Russell, 1997).
A rapidly expanding body of work examines faceprocessing in ASD. Faces are one class of stimulusthat can be processed featurally or configurally, butmay be so special in terms of evolutionary signifi-cance and developmental expertise that findings fromface studies cannot be generalised to other stimulusclasses (see, e.g. Suzuki & Cavanagh, 1995). A fullreview of face processing in ASD is beyond the scopeof the present paper. However, a number of findingssuggest abnormally feature-based face processing inASD (e.g. Deruelle, Rondan, Gepner, & Tardif, 2004;Hobson, Ousten, & Lee, 1988), although there arealso mixed (e.g. Teunisse & de Gelder, 2003) andcontrary findings (e.g. Rouse, Donnelly, Hadwin, &Brown, 2004).
Conflicting Findings
As well as fairly consistent findings from rela-tively robust tasks that appear to be good probes ofweak coherence, e.g., Block Design, Embedded Fig-ures Test (EFT) and homograph reading, there havebeen inconsistent and negative findings. The earlyfinding of more accurate (context-independent)judgement of visual illusions (Happe, 1996), forexample, has not been replicated in later studies byRopar and Mitchell (1999, 2001), using computerisedand paper-and-pencil tasks—although the originalfinding of lack of benefit from 3-D disembedding hasnot been explored in subsequent studies. Scott,Brosnan, and Wheelwright (submitted for publica-tion) suggest a possible explanation for conflictingfindings in terms of test-question wording; in theirstudy participants with ASD made the typical mis-judgements when asked, for example, whether twolines of an illusion ‘‘looked the same length’’, butwere more accurate than controls when askedwhether the two lines ‘‘were the same length’’.
The Navon hierarchical figures (e.g. an Hcomposed of small Ss; Navon, 1977) have alsoproduced inconsistent results, with some researchers(e.g. Mottron, Burack, Stauder, & Robaey, 1999)finding the normal global advantage in groups withASD, or the lack of such an advantage in typicallydeveloping comparison groups. This task is known tobe sensitive to small variations in methodology;Navon (2003), in a recent review of the hierarchicalfigure literature, has questioned the use of directed(i.e. selective) attention methodologies, and figures inwhich one of the elements is strictly foveal. A study
JolliffeandBaron-C
ohen
(2000)
17HFA
CA
31,FIQ
105
Globalintegrationtest
(arrangesentencesfor
coherentstory)
ASD<TD
arrangingsentencescoherently(nsin
condition
usingtemporalcues)
17ASCA
28,FIQ
107
Globalinferencestest
ASD<TD
makingcontext-appropriate
inferencesin
short
stories
17TD
CA
andFIQ
matched
Norbury
&Bishop(2002)
10HFA
CA
9,Ravens108,VIQ
91
Story
comprehensionandinference
task
Nogroupdifferencesin
story
comprehension
16SLICA
9,Ravens99,VIQ
83
Poorerinference
(relativeto
literal)questionperform
ance
inHFA
24PLICA
9,Ravens105,VIQ
89
18TD
CA
9,Ravens111,VIQ
107
Note:In
order
togroupstudiesbytask/domain,somepapersappearmore
thanonce.Studiesfrom
asingle
publicationshare
asuperscriptletter.
Key:AS=
Asperger
Syndrome;
ASD
=autism
spectrum
disorders;
BPVS
=British
Picture
Vocabulary
Scale;CA
=chronologicalage(inyears
unless
otherwisespecified);
(C)EFT=
(Children’s)Embedded
FiguresTest;DAS
=DifferentialAbilityScales;
DS
=DownSyndrome;
HFA
=highfunctioningautism
;MH
=mentallyhandicapped;
NVIQ
=nonverbalIQ
;ns
=statisticallynon-significant;RA
=readingage;SLI
=specificlanguageim
pairment;T=
typical;TD
=typicallydeveloping;ToM
=theory
of
mind;VMA
=verbalmentalage.
Weak Coherence
by Plaisted, Swettenham, and Rees (1999) showedlocal advantage and interference from local to globalstimuli in a condition where participants with ASDwere required to divide attention between local andglobal levels, but not in a selective attention task inwhich participants were instructed to pay attentionto, for example, the global level. Reduced or absentglobal advantage may only be evident, then, whenparticipants with ASD are not directed to attend toglobal information.
These findings underscore the importance ofopen-ended tasks in capturing what appears to be aprocessing bias towards features rather than a pro-cessing deficit for wholes. A similar finding is seenwith verbal semantic materials, where alerting chil-dren with ASD to the special status of homographs(Snowling & Frith, 1986) removed the otherwiserobustly found ASD-specific failure to disambiguatepronunciation/meaning on the basis of precedingsentence context (Frith & Snowling, 1983; Happe,1997; Jolliffe & Baron-Cohen, 1999; Lopez & Lee-kam, 2003). Lopez, Donnelly, Hadwin, and Leekam(2004) demonstrated the same effect for face process-ing; participants with ASD showed configuralprocessing of faces in attentionally cued, but not innon-cued, conditions.
Other negative findings may help to demarcatethe boundaries of weak coherence. People withautism do appear to integrate the properties of asingle object (e.g. colour and form in a visual searchtask; Plaisted et al., 1998a, b; but see Plaisted,Saksida, Alcantara, & Weisblatt, 2003), and toprocess the meaning of individual words (in Strooptasks; Eskes, Bryson, & McCormick, 1990; Frith &Snowling, 1983) and objects (in memory tasks; Ameli,Courchesne, Lincoln, Kaufman, & Grillon, 1988;Pring & Hermelin, 1993). It seems to be in connectingwords or objects that coherence is weak, althoughLopez and Leekam (2003) showed that straightfor-ward priming from a word or scene (or perhaps localelements of the scene) does occur in autism.
Local vs. Global Coherence?
Clearly, people with autism can connect infor-mation of certain sorts, for example in puttingtogether the elements of their daily routine (disrup-tion to which may be so distressing), accumulatingconnected facts within a narrow domain (e.g. calen-drical calculating), or placing visual elements incoherent relation to one another when drawing.These examples may reflect alternatives to truly
configural global processing, such as item-to-itemprocessing (chaining), or intra-domain coherence.Chaining may be seen in, for example, picturesequencing tests such as the Wechsler scales PictureArrangement subtest, where a coherent story must bemade by arranging pictures shown on separate cards.This would appear to require central coherence.However, many such stories can be completed bychaining, i.e. linking one picture to the next, withouthaving to take into account more than the adjacentpicture/episode—that is only ‘‘local’’ and not ‘‘glo-bal’’, or central, coherence is needed. This sort oflocal coherence may also be sufficient to set upschemas of an event, routine, or route.
The second type of local coherence involvesconnecting information within a narrow domain, suchas connecting facts about the calendar to develop a‘‘coherent’’ representation supporting calendrical cal-culation. As Heavey (1999, 2003) has speculated, thissystem can be built up from small local parts. Calen-drical calculation may not require more coherencethan, say, grammatical processing—also notablyintact in many people with autism—which emergesfrom a closed modular system (see below for relatedissues on Baron-Cohen’s systemizing theory).
In reviewing the research on coherence, it isnotable that many tasks assume or even create aninherent trade-off between processing at the local andglobal levels. For example, in the Navon task, there iscompetition and interference between local andglobal levels. In the EFT, successful performance istaken as both a measure of how salient the partis, and how (relatively) weak the camouflaging gestaltis, for the participant. In the Sentence Completiontest, a local completion (‘The sea tastes of salt and...’,‘‘pepper’’) may reflect either strength of local associ-ates or lack of available global completions. Thisaspect of task design may obscure the possibility thatlocal and global processing in other situations maynot necessarily act in competition. At least in terms ofindividual or clinical group differences, a person/group characterised by good featural or detail-focused processing need not, necessarily, be poor atglobal processing. In principle, in a two by twomatrix, all four quadrants might be filled; somepeople showing good local and good global process-ing, some poor processing of both levels, and somegood at either local or global only. This raises thequestion of whether individual differences mayreflect, in part, the ability to shift between modes ofprocessing, itself perhaps an ability falling under theumbrella term ‘‘executive function’’ (see below).
Happe and Frith
Universality and Specificity
An important recent trend is to look beyondgroup effects to report the proportion of a participantgroup that shows the reported pattern of difficulties/abilities. Where such data are reported (e.g. Jarrold &Russell, 1997; Scheuffgen, 1998), the findings suggestthat weak coherence may be characteristic of only asubset of the ASD population. This is, perhaps, notsurprising for at least two reasons. First, suchfindings are typical for tests of any account ofautism, such as the theory of mind and executivedysfunction accounts. They likely reflect the enor-mous heterogeneity within the group we currentlydesignate, on behavioural criteria, as having ASD.Second, any test is an indirect probe of the underlyingcognitive functions of interest, and there are typicallymany ways both to pass and to fail a test. Thetest–retest reliability and other psychometric proper-ties of the experimental tasks used are also, typically,unknown. Despite this, individual analyses areimportant, as they may eventually shed light oncognitively meaningful subgroups, which might differin their aetiology, behavioural features, prognosis, orresponse to intervention.
The specificity of weak coherence is also ofinterest; do other clinical groups share this cognitivestyle? Four different clinical groups provide someempirical evidence of local processing bias; schizo-phrenia, Williams Syndrome, depression, and righthemisphere damage. Schizophrenia has been pro-posed to be characterised by featural vs. configuralprocessing (e.g. Chen, Nakayama, Levy, Matthysse,& Holzman, 2003; John & Hemsley, 1992), and non-clinical groups high in schizotypy show reduced useof context resulting in superior performance oncertain tasks (Uhlhaas, Silverstein, Phillips, & Lovell,2004). People with Williams Syndrome have beendescribed as showing unusually featural processing(e.g. copying components from hierarchical letters;Bellugi, Lichtenberger, Jones, Lai, & George, 2000),although processing style for faces, other visuo-spatial material, and verbal material should probablybe considered separately in this group, who showvisuo-spatial deficits alongside a strong preference forfaces. Individuals with depression/anxiety may showan imbalance in global/local processing, with nega-tive mood related to more detail-focused or analyticprocessing in clinical groups (e.g. Derryberry &Tucker, 1994; Hesse & Spies, 1996), and followingmood induction in non-clinical samples (e.g. Gasper& Clore, 2002). Whether negative mood plays a part
in coherence findings in ASD is unclear; anxiety anddepression are common in higher ability ASD.Individuals with acquired right hemisphere damageshow deficits on visuo-spatial constructional tasks,maintaining details but missing global configuration(Robertson & Lamb, 1991). Discourse also becomesfragmented in such patients, with difficulties integrat-ing verbal information and extracting gist (Benowitz,Moya, & Levine, 1990). Developmental right hemi-sphere damage also seems to disrupt configuralprocessing, as reflected, for example, in piecemealdrawing styles (Stiles-Davis, Janowsky, Engel, &Nass, 1988). It is important to bear in mind, however,that similar behaviour may not necessarily indicatesimilar underlying cognitive processes. Until thesedifferent clinical groups have been compared, along-side ASD, on the same coherence tasks, it remainsunclear whether they truly share the same underlyingcognitive style.
In the first direct comparison of clinical groups,Booth, Charlton, Hughes, and Happe (2003) testedboys with ASD or with Attention Deficit/Hyperac-tivity disorder (ADHD) on weak coherence andexecutive function tasks (see also below). They foundthat the ASD but not the ADHD participantsshowed detail-focused drawing styles. The samegroups could also be distinguished on verbal testsof coherence (Happe & Booth, in preparation);despite their inhibition problems, the ADHD groupdid not make the sorts of local sentence completionsfound to be characteristic of children with ASD (e.g.‘You can go hunting with a knife and...’, ‘‘fork’’).
Weak Coherence as a Normal Individual Difference
The notion of weak coherence as a processingbias, rather than deficit, lends itself to a continuumapproach, in which weak coherence is seen as one endof a normal distribution of cognitive style, and peoplewith ASD, and perhaps their relatives, are placed atthe extreme end of this continuum. The oppositecognitive style, strong coherence, might be charac-terised as a tendency to process gist and global format the expense of attention and memory for detail andsurface form. Thus, while the person with weakcoherence may be poor at seeing the bigger picture,the person with strong coherence may be a terribleproof reader. It is important, in this working hypoth-esis, to recall that these styles represent only biases;the person with strong coherence can, by an effort ofwill, turn their attention to details such as remem-bering unconnected facts for an exam, just as the
Weak Coherence
person with weak coherence can, if really required to,extract the gist of a long speech.
Is there empirical evidence for the postulatedindividual differences in coherence in the generalpopulation? There is some evidence of normal indi-vidual differences in local–global processing frominfancy (Stoecker, Colombo, Frick, & Allen, 1998),childhood (Chynn, Garrod, Demick, & DeVos,1991), and adulthood (Marendaz, 1985). Sex differ-ences have been reported on tasks thought to taplocal–global processing (Kramer, Ellenberg, Leon-ard, & Share, 1996), although type (local/global) anddomain (visuo-spatial/verbal) of processing are oftenconfounded. Thus the typical (small) male superiorityon visuo-spatial tasks may have contributed toapparent male bias for local processing, as seen forinstance on the EFT. Tests benefiting from featuralprocessing in auditory and verbal domains are neededto build up a fuller picture.
The Embedded Figures Test (EFT) originated asa test of ‘‘field independence’’, and the notion ofindividual differences in coherence recalls this postu-lated cognitive style (Witkin, Dyk, Faterson, Goo-denough, & Karp, 1962; Witkin & Goodenough,1981). Field independence (FI) refers to a cognitivestyle characterised by the tendency to see objects inone’s field of vision as discrete units, distinct from thefield as a whole. The designs in the EFT takeadvantage of gestalt principles to create wholes thatare difficult to break into component parts. Fieldindependence is therefore defined by good EFTperformance—as also seen in ASD. It might be amistake, however, to equate FI with weak centralcoherence; while FI people are conceptualised assucceeding on EFT because of their ability to see, butresist, the gestalt, people with weak coherence arepostulated to be good at this test precisely becausethey do not spontaneously attend to the gestalt,instead seeing the figure first in terms of its parts.Whether the suggested distinction between FI andweak coherence holds up is a matter for empiricalinquiry. However, it is possible to derive distinctpredictions for FI and weak central coherence. Forexample, when people with weak coherence makeerrors on the Wechsler Block Design subtest, theseshould be of a type that preserve design details andviolate configuration. When FI people make errorson the BD, however, they (like field dependentpeople) would be expected to make errors reflectinga relative failure to resist the gestalt—i.e. errors thatpreserve the configuration but violate the details (e.g.Kramer, Kaplan, Blusewicz, & Preston, 1991). In
other words, global processing remains the defaultfor FI people according to Witkin’s theory, whilelocal processing is proposed to be the default forindividuals with weak coherence.
Weak Coherence and the Broader Autism Phenotype
Thinking about weak coherence as one end of anormal continuum in cognitive style suggests that thismay be one aspect of the broader autism phenotype,and that tests of coherence might be useful for familystudies of the genetic contribution to ASD. Happe,Briskman, and Frith (2001) studied the parents ofboys with ASD using the EFT, Un/Segmented BlockDesign, visual illusions and sentence completion testsas coherence measures. They found that around halfof the fathers and a third of the mothers showedconsistent weak coherence, or detail-focus, across thetest battery (often shown in superior performance).Self-report of ‘‘eye for detail’’ traits matched coher-ence test performance, while self-report of socialdifficulties or shyness did not (Briskman, Happe, &Frith, 2001). This suggests that the social and non-social aspects of the broader autism phenotype areindependent. Among comparison groups (parents ofboys with dyslexia, or with no disorder) significantlyfewer participants showed consistent detail focus, ontests or self-report. These findings suggest that weakcoherence can be found in well-adapted, healthy andintelligent adults—indeed, it may be this aspect of thebroader autism phenotype that underlies the appar-ently higher prevalence of family members in engi-neering (Baron-Cohen et al., 1997), and otherprofessions where, putatively, attention to detailmay be important. This aspect of the broaderphenotype, unlike the social deficits, may haveadvantages for reproductive fitness, and its persis-tence in the gene pool is not hard to explain.
Weak Coherence in Relation to other Accounts
of Autistic Signs and Symptoms
One of the changes in the working hypothesis ofthe weak coherence account has concerned therelationship between coherence and social deficits inautism (Frith & Happe, 1994). Frith’s originalconception (Frith, 1989) gave weak coherence acentral and causal role, with problems integratinginformation for high level meaning underlying thedeficits in social understanding, which Frith and hercolleagues so influentially characterised as problemsin ‘‘theory of mind’’ (Baron-Cohen, Leslie, & Frith,
Happe and Frith
1985). However, the fact that detail-focused process-ing can be found across the autism spectrum,regardless of level of theory of mind performance(Happe, 1997; Jolliffe & Baron-Cohen, 1997, 1999)suggests that these two aspects of the phenotype maybe distinct (see Happe, 2000, 2001, for a fulldiscussion of possible relationships). Indeed, evidencefrom recent behaviour genetic studies of autism-related characteristics in typically developing twinssuggests somewhat distinct genetic contributions tothe social vs. the non-social/restricted and repetitivebehaviour domains (Ronald, Happe, & Plomin, inpress). It currently appears most plausible to considerautism the result of anomalies affecting a number ofcore cognitive processes (Happe, 2003), includingglobal–local processing (central coherence or one ofthe alternative conceptualisations discussed below),social cognition (e.g. theory of mind), and executivefunctions. In this framework, the weak coherenceaccount does not attempt to explain all aspects of theautism phenotype, such as primary social abnormal-ities, although it seems plausible that detail focusmight further interfere with already abnormal socialfunctioning. For example, featural processing mightdisrupt recognition of facial emotion, and reducecontext-sensitive interpretation of social behaviour orutterances.
Investigations of the relationship between cen-tral coherence and theory of mind have beensomewhat mixed. Weak coherence seems to cha-racterise people with autism regardless of theirtheory of mind ability in studies using perceptual(visual illusions; Happe, 1996), and semantic tasks(homograph reading; Happe, 1997). For example,Happe (1994) found that theory of mind taskperformance was related to performance on theComprehension subtest of the Wechsler scales (com-monly thought to require pragmatic and social skill),but not to performance on the Block Design subtest(a marker of weak coherence) in a large sample ofindividuals with ASD. Morgan, Maybery, andDurkin (2003) also found no relation between weakcoherence (measured by EFT) and social skills (jointattention, pretend play), among preschoolers withASD. However, Jarrold, Butler, Cottington, andJimenez (2000) reported an inverse relation betweenperformance on Baron-Cohen’s ‘‘Eyes task’’ (tap-ping social cognition) and speed on the EFT in asample of undergraduates; and in a group ofchildren with autism and typically-developingchildren, false belief task performance was nega-tively correlated with EFT performance, with the
correlation reaching significance once verbal mentalage was partialled out. Pellicano, Maybery, andDurkin (in press), on the other hand, found norelation between performance on EFT, BlockDesign and two other tests aimed at assessing weakcoherence (which loaded on two separate factors),and tests of theory of mind in a sample of typicallydeveloping 4- and 5-year-olds, with age and IQpartialled out.
Longitudinal studies would clearly be helpful ininvestigating possible causal relations. To date theonly data of this type are from a study withadolescents and adults. Berger et al. (1993) foundthat cognitive shifting, but not a measure of disem-bedding, predicted social understanding in high-functioning people with autism (aged 16–25 years)at 2-year follow-up (see also Berger et al., 2003).
Weak Coherence in Relation to other Deficit Accounts
A prominent account addressing the non-socialaspects of ASD posits executive dysfunction at theroot of the characteristic rigid and repetitive behav-iour. Executive function is an umbrella term coveringa range of higher-order cognitive abilities necessaryfor flexible and adaptive behaviour in the service ofnovel goals. As such, executive function might beseen to encompass the processing of information incontext for global meaning, i.e. central coherence.Findings currently attributed to weak coherencemight be explained by executive dysfunction: failureto process information globally might be argued tofollow from problems in shifting between local andglobal levels, provided local processing is consideredto be the default. Limitations of working memorymight bias performance towards smaller fragments ofinformation. Similarly, poor planning might result inpiece-meal approaches to novel tasks.
To date, there have been three investigations ofthe possible relation between coherence and executivefunctions. Teunisse, Cools, van Spaendonck, Aerts,and Berger (2001) found that weak coherence andpoor shifting were more common among high-func-tioning adolescents with autism than among com-parison typically-developing participants, but neitherwas universal. Performance on the two types ofmeasure was unrelated and did not correlate withsymptom severity or social ability. Pellicano et al. (inpress) found a significant relationship between exec-utive function tasks and some but not all tests aimedat assessing coherence in her study of 4- and 5-year-old typically developing children. However, the
Weak Coherence
choice of tasks is likely to have confounded process-ing style and visuo-spatial ability. Booth et al. (2003)examined directly the possible role of one executivefunction, planning, on global/local processing in adrawing task. They compared boys with ASD andboys with ADHD, as well as a typically developingcomparison group, all matched on age and IQ. Adrawing task requiring planning ahead (to add arequested internal element), showed the predictedplanning deficits in both clinical groups, while anal-ysis of drawing style showed that piecemeal drawing,e.g., starting with features or drawing detail to detail,was characteristic of the ASD group only. Perfor-mance on the executive function and central coher-ence elements of the task did not correlate in theclinical groups, and Booth et al. conclude that weakcoherence is not common to all groups with executivedysfunction, and that poor planning cannot explaindetail-focus in autism. Notwithstanding this evidencethat weak coherence findings are not a mere side-effect of executive dysfunction in planning or inhibi-tion, there may be important theoretical sharedground between these two accounts. The executivefunction metaphor of the ‘‘chief executive’’, intop–down control of lower resources, certainly reso-nates with Frith’s original notion of central coher-ence. Many aspects of autism seem well characterisedas manifestations of reduced top–down modulation(Frith, 2003), and local or piecemeal processing mightbe postulated to be the default when control fromabove (the CE) is weakened or absent. In this sense,coherence might be seen as one aspect of executivefunction. However, coherence would be unlike mostprocesses grouped under the executive functionumbrella, in so far as the neural substrate forcoherence is not hypothesised to be in the frontallobes, and coherence is thought to be a property oflow- as well as higher-level systems.
Alternative Accounts of Weak Coherence Findings
In recent years, there has been a renewal ofinterest in perceptual processes in autism, as reflectedin a number of alternative theoretical accounts of thefindings underpinning the weak coherence theory.Theories by Plaisted, by Mottron and by Baron-Cohen are notable amongst these. Plaisted (2000,2001) has suggested that the mechanism underlyingweak coherence effects may operate at the perceptuallevel, and specifically lie in enhanced discriminationand reduced generalization. Plaisted hypothesizes thatpeople with autism process features held in common
between objects relatively poorly, and process featuresunique to an object, i.e. those that discriminate items,relatively well. This is thought to underlie the patternof superior visual search (Plaisted et al., 1998a;O’Riordan et al., 2001), superior discriminationlearning of highly confusable patterns (Plaistedet al., 1998b), and poor prototype extraction (Plaistedet al., submitted for publication; see also Klinger &Dawson, 2001), demonstrated by Plaisted, O’Riordan,and colleagues in an elegant series of studies.
Mottron and colleagues also situate the mecha-nism for weak coherence effects at the level ofperception. Their ‘‘enhanced perceptual functioning’’(EPF) framework posits overdeveloped low-levelperception and atypical relationships between low-and high-level processing (see Mottron & Burack,2001). On this account, ‘persons with autism may beover-dependent on specific aspects of perceptualfunctioning that are excessively developed and, as aconsequence, more difficult to control and moredisruptive to the development of other behavioursand abilities (p. 137)’. While this account, like weakcoherence, has to do with atypicalities in the relationsbetween lower and higher level processing, andaddresses much of the same data, EPF predictssuperiority on some tasks that weak coherence doesnot; ‘autism is characterised by the enhancement ofseveral functions that share the properties of low-level processing not necessarily associated with animbalance between local and global processing(p. 139)’. An example might be the finding thatparticipants with high-functioning autism were betterthan matched typical comparison participants oncertain map tasks, as indicated by superior accuracyin graphic cued recall of a path and shorter learningtimes in a map learning task that may reflect superiordetection and reproduction of simple visual elements(Caron, Mottron, Rainville, & Chouinard, 2004). It ishard to see how the weak coherence account couldpredict this finding.
By contrast, other data cited in support of EPFfit well with the weak coherence prediction of detail-focused processing bias and superior local processing;e.g. higher pitch sensitivity (Bonnel et al., 2003), andparity between phonological and semantic cueing inverbal memory (Mottron, Morasse, & Bellville,2001). Mottron and colleagues cite in favour of theirEPF proposal, but also compatible with Plaistedet al.’s account, the finding that people with autismshow enhanced local processing and intact globalprocessing of musical stimuli (Heaton et al., 1998;Mottron et al., 2000; but see Foxton et al., 2003).
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While such findings may be at odds with the originaldescription of weak coherence, they are in keepingwith the suggestion that weak coherence is a cognitivestyle or bias—that is, that global processing ispossible for people with autism, but that localprocessing is preferred in open-ended tasks.
Baron-Cohen (2002, 2003) has proposed anempathising-systemizing account of ASD, of whichthe suggested facility for systemizing is relevant to theweak coherence account. Systemizing refers to thedrive to analyse and construct systems, essential towhich, on Baron-Cohen’s account, is an initial atten-tion to exact detail. This attention is proposed toexplain some of the coherence findings, such assuperior EFT performance. Where the systemizingaccount makes distinct predictions from the coherenceaccount, according to Baron-Cohen, Richler, Bisarya,Gurunathan, Wheelwright (2002), is in regard to theability to master a new system, discovering the rulesand regularities and relationships between underlyingparameters. This ability to integrate informationabout the components of a system is seen as theantithesis of weak coherence. However, as discussedabove, some systems (e.g. bus route numbering) maybe fathomable through ‘local’ coherence, providedthat simple if-then rules operate without context-dependent effects. Mastery of such systems would notbe counter to the coherence account. Clearly the keydata needed would identify which systems people withASD do and do not master quickly from scratch. Thedata available on systemizing largely comprise self-ratings of abilities and preferences (e.g. Baron-Cohenet al., 2002), and have yet to be validated againstactual performance (but see Lawson, Baron-Cohen, &Wheelwright, 2004). However, the systemizingaccount draws attention to an important aspect ofASD not encompassed by the coherence account—thedesire to collect and connect information withincircumscribed narrow areas of interest.
Possible Mechanisms for Weak Coherence
A major limitation of the coherence account todate is the lack of specification of the mechanism, atboth the cognitive and neural levels, that underliesdetail-focused processing bias among people withASD. The alternative accounts respond in part to thischallenge. Important questions remain: should wethink of a single, central mechanism integratinginformation from diverse modules/systems, forhigher-level meaning/configuration? Or should coher-ence be thought of as a property of each subsystem, a
setting for the relative precedence of global vs. localprocessing, repeated at different levels throughout thebrain? Data are needed, in this respect, regardingindividuals’ performance on coherence tests acrossand within a number of domains.
Examining a possible attentional mechanism forsome of the findings of detail-focused processing invisual tasks, Mann and Walker (2003) (see alsoRinehart, Bradshaw, Moss, Brereton, & Tonge,2001) found evidence of difficulty broadening thespread of visual attention; children with autism, incontrast to typically developing and intellectuallyimpaired groups, were slower to respond to a largecrosshair if it appeared after a small crosshair stimulus,but not vice versa. Mann and Walker (2003) suggestthat difficulty in ‘‘zooming out’’ may account for someof the findings in the coherence literature (e.g. goodEFT performance), without the need to postulateproblems in integrating stimuli. However, Burack(1994) found performance in ASD indicative of an‘attentional lens...inefficient in contracting its focus’;the beneficial effect of awindowdirecting attention in aforced-choice RT task was negated by the presence ofdistractor stimuli, whether near or far from the target.
Computational Models
Computer models may suggest possible cognitiveand neural bases for weak coherence. Several param-eters in such models can be altered to simulate detailfocus and poor generalisation. Suggestions to dateinclude excessive conjunctive coding, high inhibitionrelative to excitation, excessive inhibitory feedback,and an increase in number of key processing units.McClelland (2000) suggested that excessive conjunc-tive neural coding in at least some brain regions mightlimit generalisation of learning, due to ‘‘hyperspecific-ity’’ of representations. O’Loughlin and Thagard(2000), using their theory of coherence as constraintsatisfaction, simulated weak coherence on the homo-graph task in a connectionist network with unusuallyhigh inhibition compared to excitation. Gustafsson(1997) suggested that excessive inhibitory feedbackmight result in narrow feature maps, and over-speci-ficity of processing, and Cohen (1994) presented acomputational model of ASD in which lack of gener-alisation results from an increase in units.
Neural Models
At the neural level, two types of mechanism havebeen proposed in relation to findings of local
Weak Coherence
processing bias in ASD. The first type of mechanismposits a deficit in a specific pathway or region of thebrain. The second type proposes diffuse changes inneuronal connectivity. Variants of each type ofaccount are briefly reviewed below.
Spencer et al. (2000) proposed a specific pathwayabnormality underlying ASD. They found raisedcoherent motion thresholds in ASD, and suggestedthese were due to abnormal processing in the dorsalstream/magnocellular pathway, thought to be spec-ialised for low spatial frequency information. Milneet al. (2002) replicated this finding and made anexplicit theoretical connection between weak centralcoherence and magnocellular pathway impairments.Milne (unpublished Ph.D. thesis) found a relation-ship between performance on EFT and motioncoherence in a subgroup of individuals with ASD,and Pellicano, Gibson, Maybery, Durkin, and Bad-cock (2005) reported a significant correlation betweenthese tests in a separate sample of children with ASD.Deruelle et al. (2004) provide indirect evidence insupport of the magnocellular pathway account. Theydemonstrated better performance by participantswith ASD using high- vs. low-spatial frequencystimuli (filtered pictures of faces). Pellicano et al.(2005) and Bertone et al. (2003) have refined thenature of the motion perception deficit in ASD.Children with ASD showed normal flicker contrastsensitivity, suggesting intact lower-level dorsal streamfunctioning, alongside raised global motion thresh-olds (Pellicano et al., 2005). Bertone et al. (2003)report raised thresholds for second-order (texture-defined), but not first-order (luminance defined),motion in ASD. The authors interpret their findingsas showing that processing of motion breaks downonly at complex neural levels, where integrativefunctioning is necessary.
While Spencer et al. and Milne et al. haveproposed a specific pathway as the locus for weakcoherence anomalies, a specific region implicated inglobal and integrative processing is the right hemi-sphere. Individuals with acquired right hemispheredamage show deficits integrating information forglobal form and meaning (see above). Functionalimaging work, too, suggests a role for right hemi-sphere regions in configural processing. For example,Fink et al. (1997) found evidence of right lingualgyrus activation during attention to global aspects ofa hierarchical figure, and left inferior occipital acti-vation during local focus. Electrophysiological (ERP)studies, too, suggest right hemisphere activity duringglobal (vs. local) tasks (e.g. Heinze, Hinrichs, Scholz,
Burchert, & Mangun, 1998), although this is notobserved under all circumstances (see, e.g. Volberg &Hubner, 2004, for discussion). Most recently, thetechnique of transcranial magnetic stimulation hasbeen used to demonstrate the role of right posteriorparietal lobe in the perception of global aspects ofhierarchical figures, although interestingly this later-ality appears to be true only for right-handers and isreversed in left-handed people (Mevorach, Humph-reys, & Shalev, 2005). To date, however, there is littleconclusive evidence of localised and specific struc-tural damage in ASD. Some brain imaging studies ofindividuals with ASD have found right hemisphereabnormalities (e.g. McKelvey, Lambert, Mottron, &Shevell, 1995; Waiter et al., 2005), but evidence ofdamage in (bilateral) limbic, frontal and cerebellarregions has also been reported and it is by no meansclear which anomalies are specific and universal toASD. The only functional imaging study of glo-bal–local processing in ASD to date, which used theEFT, did not find clear evidence for lateralisedabnormalities (Ring et al., 1999). Group comparisonsindicated greater frontal and parietal activity in thetypical group, and greater activation of occipitalregions in the ASD group, but the lack of a well-matched control task in this study limits the conclu-sions that can be drawn.
Perhaps more intuitively appealing than local-ised neural accounts, are proposals that weak coher-ence is the result of reduced connectivity throughoutthe brain. A number of variations of this type ofaccount have been proposed, including reducedconnectivity due to lack of synchronisation of acti-vation (Brock, Brown, Boucher, & Rippon, 2002),lack of connecting fibres (Just, Cherkassky, Keller, &Minshew, 2004), and failure of top–down modulation(Frith, 2004). Brock et al. (2002) have put forwardperhaps the most thorough working hypothesis ofthis type in which they propose that brain speciali-sation in ASD develops without normal cross-talkbetween regions, and that weak coherence emergesdue to lack of synchronisation of neural activitynecessary to bind parts into wholes. They predictreduced synchronisation of high-frequency gammaband activity between local networks, and suggestways in which their temporal binding deficit hypoth-esis might be tested using EEG techniques.
Also suggesting reduced connectivity, Just et al.(2004) reported results from functional imaging ofvolunteers with ASD during a sentence comprehen-sion task. They found patterns of activation in theASD vs. control group suggestive of increased
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low-level processing, and reduced functional connec-tivity. A similar finding was previously reported byCastelli, Frith, Happe, and Frith (2002). Just et al.propose an ‘‘underconnectivity’’ theory, in whichsymptoms of autism result from underfunctioning ofintegrative circuitry responsible for integration ofinformation at the cognitive and neural levels. Thereis considerable evidence of abnormal brain connec-tivity in ASD (for review see Belmonte et al., 2004),including recent findings of reduced white matter (e.g.Chung, Dalton, Alexander, & Davidson, 2004), anddisrupted white matter tracts (Barnea-Goraly et al.,2004), which might result from excessive braingrowth at key periods (Courchesne, 2004), or, morespeculatively, disruptions to developmental trajecto-ries of serotonin synthesis (Chugani et al., 1999).
Connectivity of lower brain regions can also bealtered by top–down feedback (Friston & Buechel,2000). Frith (2004) has suggested that a lack oftop–down modulation, due to failure of early neuralpruning of feedback connections, could be a cause ofabnormal connectivity. Decreased functional connec-tivity, in this model, would result from misconnec-tions due to unpruned synapses (see also Belmonte &Yurgelun-Todd, 2003). Such a suggestion fits wellwith proposed computational models in whichreduced generalisation results from too many neuralunits, and with anatomical evidence of larger andheavier brains in ASD (perhaps due to failures ofsynaptic pruning and programmed cell death; forreview see Courchesne, 2004). For example, Lee(2002) demonstrated top–down influences on theactivity of early visual neurons using single cellrecording techniques, and suggests that top–downinteraction, through recurrent feedback connections,allows contextual information to influence earlyperceptual processing. If such feedback connectionswere abnormal in ASD, perceptual abnormalitiesmight result due to lack of modulation by higher-level‘meaning’ (e.g. expectation, context).
CONCLUSIONS
There is a strong and growing body of evidencethat people with ASD are characterised by superiorperformance on tasks requiring detail-focused pro-cessing. Whether this superiority is achieved at thecost of normal global processing is less clear, and theweak coherence account has moved towards anemphasis on superiority in local processing ratherthan deficit in global processing. It has also become
clear that people with ASD can process globally formeaning when explicitly required to do so, leading tothe notion of a processing bias for local over globallevels of information, best tapped by open-endedtasks. Whether this bias is specific to ASD, comparedwith other clinical groups, is as yet unclear—althoughthere is some evidence that it may form part of thebroader autism phenotype. Results to date suggestweak coherence is not reducible to executive dys-function, and most studies suggest weak coherence isindependent of deficits in social cognition. Manyquestions remain to be answered concerning themechanism for weak coherence, at both the cognitiveand neural levels. Growing evidence of disturbedneural connectivity in ASD holds promise for furtherunderstanding the brain basis of weak coherence.Among the remaining challenges is the need toestablish relationships between weak coherence, oralternative accounts of detail-focused processing bias,and real-life abilities and difficulties. Finally, thenotion of weak coherence has yet to be translatedinto educational approaches, which may, perhaps,prove the ultimate test of this theory’s veracity andvalue.
ACKNOWLEDGMENTS
Both authors were supported by grants from theMedical Research Council at the time of writing(grant G9900087 to F.H. and G9716841 to U.F.). Wewould like to thank Rhonda Booth for her helpfulcomments on the manuscript.
REFERENCES
Ameli, R., Courchesne, E., Lincoln, A., Kaufman, A. S., &Grillon, C. (1988).Visualmemory processes in high-functioningindividuals with autism. Journal of Autism and DevelopmentalDisorders, 18, 601–615.
American Psychiatric Association. (1994). Diagnostic and Statisti-cal Manual of Mental Disorders, 4th edition (DSM-IV).Washington, DC: American Psychiatric Association.
Aurnhammer-Frith, U. (1969). Emphasis and meaning in recall innormal and autistic children. Language & Speech, 12, 29–38.
Barnea-Goraly, N., Kwon, H., Menon, V., Eliez, S., Lotspeich, L.,& Reiss, A. L. (2004). White matter structure in autism: Pre-liminary evidence from diffusion tensor imaging. BiologicalPsychiatry, 55, 323–326.
Baron-Cohen, S. (2002). The extreme male brain theory of autism.Trends in Cognitive Sciences, 6, 248–254.
Baron-Cohen, S. (2003). The essential difference: The truth aboutthe male and female brain. New York, NY: Basic Books.
Baron-Cohen, S., Leslie, A. M., & Frith, U. (1985). Does theautistic child have a ‘theory of mind’? Cognition, 21, 37–46.
Weak Coherence
Baron-Cohen, S., Wheelwright, S., Stott, C., Bolton, P., & Good-yer, I. (1997). Is there a link between engineering and autism?Autism, 1, 101–109.
Baron-Cohen, S., Richler, J., Bisarya, D., Gurunathan, N., &Wheelwright, S. (2003). The Systemising Quotient (SQ): Aninvestigation of adults with Asperger Syndrome or HighFunctioning Autism and normal sex differences. PhilosophicalTransactions of the Royal Society, Series B, Special issue on‘‘Autism: Mind and Brain’’, 358, 361–374.
Baron-Cohen, S., Wheelwright, S., Griffin, R., Lawson, J., & Hill, J.(2002). The exact mind: Empathising and systemising in aut-ism spectrum conditions. In U. Goswami (Ed.), Handbook ofcognitive development. (pp. 491–508). Malden, MA, USA:Blackwell Publishers.
Bartlett, F. C. (1932). Remembering: A study in experimental andsocial psychology. Cambridge, England: Cambridge UniversityPress.
Bellugi, U., Lichtenberger, L., Jones, W., Lai, Z., & St. George, M.(2000). The neurocognitive profile of Williams syndrome: Acomplex pattern of strengths and weaknesses. Journal ofCognitive Neuroscience, 12, 7–29.
Belmonte, M. K., Allen, G., Beckel-Mitchener, A., Boulanger,L. M., Carper, R. A., & Webb, S. J. (2004). Autism andabnormal development of brain connectivity. Journal of Neu-roscience, 24, 9228–9231.
Belmonte, M. K., & Yurgelun-Todd, D. A. (2003). Functionalanatomy of impaired selective attention and compensatoryprocessing in autism. Cognitive Brain Research, 17,651–664.
Benowitz, L. I., Moya, K. L., & Levine, D. N. (1990). Impairedverbal reasoning and constructional apraxia in subjects withright hemisphere damage. Neuropsychologia, 23, 231–241.
Berger, H. J., Aerts, F. H., van Spaendonck, K. P., Cools, A. R., &Teunisse, J. P. (2003). Central coherence and cognitive shiftingin relation to social improvement in high-functioning youngadults with autism. Journal of Clinical & Experimental Neu-ropsychology, Neurosurgery, and Psychiatry, 25, 502–511.
Berger, H. J., van Spaendonck, K. P., Horstink, M. W., Buy-tenhuijs, E. L., Lammers, P. W., & Cools, A. R. (1993).Cognitive shifting as a predictor of progress in social under-standing in high-functioning adolescents with autism: A pro-spective study. Journal of Autism & Developmental Disorders,23, 341–359.
Bertone, A., Mottron, L., Jelenic, P., & Faubert, J. (2003). Motionperception in autism: A ‘‘complex’’ issue. Journal of CognitiveNeuroscience, Neurosurgery, and Psychiatry, 15, 218–225.
Beversdorf, D. Q., Anderson, J. M., Manning, S. E., Anderson, S.L., Nordgren, R. E., Felopulos, G. J., Nadeau, S. E., Heilman,K. M., & Bauman, M. L. (1998). The effect of semantic andemotional context on written recall for verbal language in highfunctioning adults with autism spectrum disorder. Journal ofNeurology, Neurosurgery, and Psychiatry, 65, 685–692.
Beversdorf, D. Q., Smith, B. W., Crucian, G. P., Anderson, J. M.,Keillor, J. M., Barrett, A. M., Hughes, J. D., Felopulos, G. J.,Bauman, M. L., Nadeau, S. E., & Heilman, K. M. (2000).Increased discrimination of ‘‘false memories’’ in autism spec-trum disorder. Proceedings of the National Academy of Sci-ences, 97, 8734–8737.
Bonnel, A., Mottron, L., Peretz, I., Trudel, M., Gallun, E., &Bonnel, A. M. (2003). Enhanced pitch sensitivity in individualswith autism: A signal detection analysis. Journal of CognitiveNeuroscience, 15, 226–235.
Booth, R., Charlton, R., Hughes, C., & Happe, F. (2003). Disen-tangling weak coherence and executive dysfunction: Planningdrawing in Autism and ADHD. Philosophical Transactions ofthe Royal Society, 358(1430), 387–392.
Brian, J. A., & Bryson, S. E. (1996). Disembedding performanceand recognition memory in autism/PDD. Journal of ChildPsychology and Psychiatry, 37, 865–872.
Briskman, J., Happe, F., & Frith, U. (2001). Exploring the cogni-tive phenotype of autism: Weak ‘central coherence’ in parentsand siblings of children with autism. II. Real-life skills andpreferences. Journal of Child Psychology and Psychiatry, 42,309–316.
Brock, J., Brown, C. C., Boucher, J., & Rippon, G. (2002). Thetemporal binding deficit hypothesis of autism. Development &Psychopathology, 14, 209–224.
Brosnan, M. J., Scott, F. J., Fox, S., & Pye, J. (2004). Gestaltprocessing in autism: Failure to process perceptual relation-ships and the implications for contextual understanding.Journal of Child Psychology and Psychiatry, 45, 459–469.
Burack, J. A. (1994). Selective attention deficits in persons withautism: Preliminary evidence of an inefficient attentional lens.Journal of Abnormal Psychology, 103, 535–543.
Caron, M. J., Mottron, L., Rainville, C., & Chouinard, S. (2004).Do high functioning persons with autism present superiorspatial abilities? Neuropsychologia, 42, 467–481.
Castelli, F., Frith, C., Happe, F., & Frith, U. (2002). Autism,Asperger syndrome and brain mechanisms for the attributionof mental states to animated shapes. Brain, 125, 1839–1849.
Chen, Y., Nakayama, K., Levy, D., Matthysse, S., & Holzman, P.(2003). Processing of global, but not local, motion direction isdeficient in schizophrenia. Schizophrenia Research, 61,215–227.
Chugani, D. C., Muzik, O., Behen, M., Rothermel, R., Janisse,J. J., Lee, J., & Chugani, H. T. (1999). Developmental changesin brain serotonin synthesis capacity in autistic and nonautisticchildren. Annals of Neurology, 45, 287–295.
Chung, M. K., Dalton, K. M., Alexander, A. L., & Davidson, R. J.(2004). Less white matter concentration in autism: 2D voxel-based morphometry. Neuroimage, 23, 242–251.
Chynn, E. W., Garrod, A., Demick, J., & DeVos, E. (1991). Cor-relations among field dependence-independence, sex, sex-rolestereotype, and age of preschoolers. Perceptual and MotorSkills, 73, 747–756.
Cohen, I. L. (1994). An artificial neural network analogue oflearning in autism. Biological Psychiatry, 36, 5–20.
Courchesne, E. (2004). Brain development in autism: Early over-growth followed by premature arrest of growth. MentalRetardation & Developmental Disabilities Research Reviews,10, 106–111.
DeGelder, B., Vroomen, J., & Van der Heide, L. (1991). Facerecognition and lip-reading in autism. European Journal ofCognitive Psychology, 3, 69–86.
Dennis, M., Lazenby, A. L., & Lockyer, L. (2001). Inferentiallanguage in high-functioning children with autism. Journal ofAutism and Developmental Disorders, 31, 47–54.
Derryberry, D., & Tucker, D. M. (1994). Motivating the focus ofattention. In P. M. Neidenthal, & S. Kiayama (Eds.), Theheart’s eye: Emotional influences in perception and attention.(pp. 167–196). San Diego, CA: Academic Press.
Deruelle, C., Rondan, C., Gepner, B., & Tardif, C. (2004). Spatialfrequency and face processing in children with autism andAsperger syndrome. Journal of Autism and DevelopmentalDisorders, 34, 199–210.
Eskes, G. A., Bryson, S. E., & McCormick, T. A. (1990). Com-prehension of concrete and abstract words in autistic children.Journal of Autism and Developmental Disorders, 20, 61–73.
Fink, G. R., Halligan, P. W., Marshall, J. C., Frith, C. D., Frac-kowiak, R. S., & Dolan, R. J. (1997). Neural mechanismsinvolved in the processing of global and local aspects ofhierarchically organized visual stimuli. Brain, 120, 1779–1791.
Foxton, J. M., Stewart, M. E., Barnard, L., Rodgers, J., Young, A.H., O’Brien, G., & Griffiths, T. D. (2003). Absence of auditory‘global interference’ in autism. Brain, 126, 2703–2709.
Friston, K. J., & Buechel, C. (2000). Attentional modulation ofeffective connectivity from V2 to V5/MT in humans. Pro-ceedings of the National Academy of Sciences, 97, 75912–75916.
Happe and Frith
Frith, U. (1970). Studies in pattern detection in normal and autisticchildren: II. Reproduction and production of color sequences.Journal of Experimental Child Psychology, 10, 120–135.
Frith, C. (2003). What do imaging studies tell us about the neuralbasis of autism?Novartis Foundation Symposium, 251, 149–166.
Frith, C. (2004). Is autism a disconnection disorder? Lancet Neu-rology, 3, 577.
Frith, U., (1989). Autism: explaining the Enigma. Blackwell.Frith, U., & Happe, F. (1994). Autism: beyond ‘‘theory of mind’’.
Cognition, 50, 115–132.Frith, U., & Snowling, M. (1983). Reading for meaning and
reading for sound in autistic and dyslexic children. Journal ofDevelopmental Psychology, 1, 329–342.
Gasper, K., & Clore, G. L. (2002). Attending to the big picture:Mood and global versus local processing of visual informa-tion. Psychological Science, 13, 34–40.
Gepner, B., Mestre, D. R., Masson, G., & de Schonen, S. (1995).Postural effects of motion vision in young autistic children.Neuroreport, 6, 1211–1214.
Gepner, B., & Mestre, D. R. (2002). Brief report: Postural reac-tivity to fast visual motion differentiates autistic from childrenwith Asperger syndrome. Journal of Autism & DevelopmentalDisorders, 32, 231–238.
Gerland, G. (1997). A real person: Life on the outside [Translatedfrom the Swedish by J. Tate]. Souvenir Press.
Gustafsson, L. (1997). Inadequate cortical feature maps: A neuralcircuit theory of autism. Biological Psychiatry, 42, 1138–1147.
Happe, F. G. E. (1994). Wechsler IQ profile and theory of mind inautism: A research note. Journal of Child Psychology andPsychiatry, 35, 1461–1471.
Happe, F. G. E. (1996). Studying weak central coherence at lowlevels: Children with autism do not succumb to visual illusions,a research note. Journal of Child Psychology and Psychiatry,37, 873–877.
Happe, F. G. E. (1997). Central coherence and theory of mind inautism: Reading homographs in context. British Journal ofDevelopmental Psychology, 15, 1–12.
Happe, F. (1999). Autism: Cognitive deficit or cognitive style?Trends in Cognitive Sciences, 3, 216–222.
Happe, F. (2000). Parts and wholes, meaning and minds: Centralcoherence and its relation to theory of mind. In S. Baron-Cohen, H. Tager-Flusberg, & D. Cohen (Eds.), Understandingother minds: Perspectives from autism and developmental cog-nitive neuroscience. Oxford: Oxford University Press.
Happe, F. (2001). Social and non-social development in Autism:Where are the links? In J. A. Burack, T. Charman, N. Yirmiya,& P. R. Zelazo (Eds.), Perspectives on development in autism.NJ: Lawrence Erlbaum Associates.
Happe, F. (2003). Cognition in autism: One deficit or many? Autism:Neural basis and treatment possibilities(Novartis FoundationSymposium 251). Chichester: Wiley 198–212.
Happe, F., & Booth, R. (in preparation). Sentence completion: asimple test of weak coherence in typical development, autismspectrum disorders and attention deficit/hyperactivity disorder.
Happe, F., Briskman, J., & Frith, U. (2001). Exploring the cogni-tive phenotype of autism: Weak ‘central coherence’ in parentsand siblings of children with autism. I. Experimental tests.Journal of Child Psychology and Psychiatry, 42, 299–307.
Heaton, P. (2003). Pitch memory, labelling and disembedding inautism. Journal of Child Psychology & Psychiatry, 44,543–551.
Heaton, P., Hermelin, B., & Pring, L. (1998). Autism and pitchprocessing: a precursor for savant musical ability. MusicPerception, 15, 291–305.
Heavey, L. (2003). Arithmetical savants. In A. J. Baroody, &A. Dowker (Eds.), The development of arithmetic concepts andskills: Constructing adaptive expertise. Studies in mathematicalthinking and learning. (pp. 409–433). Mahwah, NJ, USA:Lawrence Erlbaum Associates, Publishers.
Heavey, L., Pring, L., & Hermelin, B. (1999). A date to remember:The nature of memory in savant calendrical calculators. Psy-chological Medicine, 29, 145–160.
Heinze, H. J., Hinrichs, H., Scholz, M., Burchert, W., & Mangun,G. R. (1998). Neural mechanisms of global and local pro-cessing: A combined PET and ERP study. Journal of CognitiveNeuroscience, 10, 485–498.
Hermelin, B., & O’Connor, N. (1967). Remembering of words bypsychotic and subnormal children. British Journal of Psy-chology, 58, 213–218.
Hesse, F. W., & Spies, K. (1996). Effects of negative mood onperformance: Reduced capacity or changed processing strat-egy? European Journal of Social Psychology, 26, 163–168.
Hobson, R. P., Ouston, J., & Lee, T. (1988). What’s in a face? Thecase of autism. British Journal of Psychology, 79, 441–453.
Jarrold, C., Butler, D. W., Cottington, E. M., & Jimenez, F. (2000).Linking theory of mind and central coherence bias in autismand in the general population. Developmental Psychology, 36,126–138.
Jarrold, C., & Russell, J. (1997). Counting abilities in autism:Possible implications for central coherence theory. Journal ofAutism and Developmental Disorders, 27, 25–37.
Jolliffe, T., & Baron-Cohen, S. (1997). Are people with autism andAsperger syndrome faster thannormal on theEmbeddedFiguresTest? Journal of Child Psychology and Psychiatry, 38, 527–534.
Jolliffe, T., & Baron-Cohen, S. (1999). A test of central coherencetheory; linguistic processing in high-functioning adults withautism or Asperger’s syndrome: Is local coherence impaired?Cognition, 71, 149–185.
Jolliffe, T., & Baron-Cohen, S. (2000). Linguistic processing inhigh-functioning adults with autism or Asperger’s syndrome.Is global coherence impaired? Psychological Medicine, 30,1169–1187.
Jolliffe, T., & Baron-Cohen, S. (2001). A test of central coherencetheory: Can adults with high-functioning autism or Asperger’ssyndrome integrate fragments of an object? Cognitive Neuro-psychiatry, 6, 193–216.
John, C. H., & Hemsley, D. R. (1992). Gestalt perception inschizophrenia. European Archives of Psychiatry and ClinicalNeuroscience, 241, 215–221.
Just, M. A., Cherkassky, V. L., Keller, T. A., & Minshew, N. J.(2004). Cortical activation and synchronization during sen-tence comprehension in high-functioning autism: Evidence ofunderconnectivity. Brain, 127, 1811–1821.
Kanner, L. (1943). Autistic disturbances of affective contact. Ner-vous Child, 2, 217–250.
Klinger, L. G., & Dawson, G. (2001). Prototype formation inautism. Development & Psychopathology, 13, 111–124.
Kramer, J. H., Kaplan, E., Blusewicz, M. J., & Preston, K. A.(1991). Visual hierarchical analysis of block design configuralerrors. Journal of Clinical and Experimental Neuropsychology,13, 455–465.
Kramer, J. H., Ellenberg, L., Leonard, J., & Share, L. J. (1996).Developmental sex differences in global–local perceptual bias.Neuropsychology, 10, 402–407.
Langdell, T. (1978). Recognition of faces: An approach to thestudy of autism. Journal of Child Psychology & Psychiatry, 19,255–268.
Lawson, J., Baron-Cohen, S.,&Wheelwright, S. (2004). Empathisingand systemising in adults with and without Asperger syndrome.Journal of Autism & Developmental Disorders, 34, 301–310.
Lee, T. S. (2002). Top–down influence in early visual processing: ABayesian perspective. Physiology and Behaviour, 77, 645–650.
Lopez, B., Donnelly, N., Hadwin, J., & Leekam, S. R. (2004). Faceprocessing in high-functioning adolescents with autism: Evi-dence forweak central coherence.VisualCognition, 11, 673–688.
Lopez, B., & Leekam, S. R. (2003). Do children with autism fail toprocess information in context? Journal of Child Psychology &Psychiatry, 44, 285–300.
Weak Coherence
Mann, T. A., & Walker, P. (2003). Autism and a deficit inbroadening the spread of visual attention. Journal of ChildPsychology and Psychiatry, 44, 274–284.
Marendaz, C. (1985). Global precedence and field dependence:Visual routines? Cahiers de Psychologie Cognitive, 5, 727–745.
McClelland, J. L. (2000). The basis of hyperspecificity in autism: Apreliminary suggestion based on properties of neural nets.Journal of Autism & Developmental Disorders, 30, 497–502.
McKelvey, J. R., Lambert, R., Mottron, L., & Shevell, M. I.(1995). Right-hemisphere dysfunction in Asperger’s syndrome.Journal of Child Neurology, 10, 310–314.
Mevorach, C., Humphreys, G. W., & Shalev, L. (2005). Attendingto local form while ignoring global aspects depends on hand-edness: evidence from TMS. Nature Neuroscience, publishedonline doi: 10.1038/nn1400.
Miller, L. K. (1999). The savant syndrome: Intellectual impairmentand exceptional skill. Psychological Bulletin, 125, 31–46.
Milne, E. (2003). Investigating the correlates of weak centralcoherence in autism. Unpublished Ph.D. thesis, University ofLondon.
Milne, E., Swettenham, J., Hansen, P., Campbell, R., Jeffries, H., &Plaisted, K. I. (2002). High motion coherence thresholds inchildren with autism. Journal of Child Psychology & Psychia-try, 43, 255–263.
Morgan, B., Maybery, M., & Durkin, K. (2003). Weak centralcoherence, poor joint attention, and low verbal ability: Inde-pendent deficits in early autism. Developmental Psychology, 39,646–656.
Mottron, L., & Belleville, S. (1993). A study of perceptual analysisin a high-level autistic subject with exceptional graphic abili-ties. Brain and Cognition, 23, 279–309.
Mottron, L., Belleville, S., & Menard, A. (1999). Local bias inautistic subjects as evidenced by graphic tasks: Perceptual hi-erarchization or working memory deficit? Journal of ChildPsychology and Psychiatry, 40, 743–755.
Mottron, L., Burack, J. A., Iarocci, G., Belleville, S., & Enns, J. T.(2003). Locally oriented perception with intact global pro-cessing among adolescents with high-functioning autism:Evidence from multiple paradigms. Journal of Child Psychol-ogy and Psychiatry, 44, 904–913.
Mottron, L., Burack, J. A., Stauder, J. E. A., & Robaey, P. (1999).Perceptual processing among high-functioning persons withautism. Journal of Child Psychology & Psychiatry, 40, 203–211.
Mottron, L., & Burack, J. A. (2001). Enhanced perceptual func-tioning in the development of autism. In J. A. Burack, T.Charman, N. Yirmiya, & P. R. Zelazo (Eds.), The developmentof autism: Perspectives from theory and research. NJ: LawrenceErlbaum.
Mottron, L., Morasse, K., & Belleville, S. (2001). A study ofmemory functioning in individuals with autism. Journal ofChild Psychology & Psychiatry, 42, 253–260.
Mottron, L., Peretz, I., & Menard, E. (2000). Local and globalprocessing of music in high-functioning persons with autism:Beyond central coherence? Journal of Child Psychology &Psychiatry, 41, 1057–1065.
Navon, D. (1977). Forest before trees: The precedence of globalfeatures in visual perception. Cognitive Psychology, 9,353–383.
Navon, D. (2003). What does a compound letter tell the psychol-ogist’s mind? Acta Psychologica, 114, 273–309.
Norbury, C. F., & Bishop, D. M. V. (2002). Inferential processingand story recall in children with communication problems: Acomparison of specific language impairment, pragmaticlanguage impairment andhigh-functioning autism. InternationalJournal of Language andCommunicationDisorders, 37, 227–251.
O’Riordan, M. A., Plaisted, K. C., Driver, J., & Baron-Cohen, S.(2001). Superior visual search in autism. Journal of Experi-mental Psychology: Human Perception & Performance, 27,719–730.
O’Loughlin, C., & Thagard, P. (2000). Autism and coherence: Acomputational model. Mind & Language, 15, 375–392.
Ozonoff, S., Strayer, D. L., McMahon, W. M., & Filloux, F.(1994). Executive function abilities in autism and Tourettesyndrome: An information processing approach. Journal ofChild Psychology and Psychiatry, 35, 1015–1032.
Pellicano, E., Gibson, L., Maybery, M., Durkin, K., & Badcock,D. R. (2005). Abnormal global processing along the dorsalvisual pathway in autism: A possible mechanism for weakvisuospatial coherence? Neuropsychologia, 43, 1044–1053.
Pellicano, E., Maybery, M., & Durkin, K. (2005). Central coher-ence in typically developing preschoolers: Does it coherenceand does it relate to mindreading and executive control?Journal of Child Psychology and Psychiatry, 4, 533–547.
Plaisted, K. C. (2000). Aspects of autism that theory of mindcannot easily explain. In S. Baron-Cohen, H. Tager-Flusberg,& D. J. Cohen (Eds.), Understanding other minds: Perspectivesfrom autism and cognitive neuroscience (2nd ed.). Oxford:Oxford University Press.
Plaisted, K. C. (2001). Reduced generalization in autism: Analternative to weak central coherence. In J. A. Burack, T.Charman, N. Yirmiya, & P. R. Zelazo (Eds.), The developmentof autism: Perspectives from theory and research. (pp.149–169). New Jersey: Lawrence Erlbaum.
Plaisted, K. C., O’Riordan, M. A. F., Aitken, M. R. F., Killcross,A. S. (submitted for publication). Catergorisation in autism:Evidence for a reduced prototype effect.
Plaisted, K., O’Riordan, M., & Baron-Cohen, S. (1998a). Enhancedvisual search for a conjunctive target in autism: A research note.Journal of Child Psychology & Psychiatry, 39, 777–783.
Plaisted, K., O’Riordan, M., & Baron-Cohen, S. (1998b).Enhanced discrimination of novel, highly similar stimuli byadults with autism during a perceptual learning task. Journalof Child Psychology & Psychiatry, 39, 765–775.
Plaisted, K., Saksida, L., Alcantara, J., & Weisblatt, E. (2003).Towards an understanding of the mechanisms of weak centralcoherence effects: Experiments in visual configural learning andauditory perception. Philosophical Transactions of the RoyalSociety of London—Series B: Biological Sciences, 358, 375–386.
Plaisted, K., Swettenham, J., & Rees, L. (1999). Children withautism show local precedence in a divided attention task andglobal precedence in a selective attention task. Journal of ChildPsychology and Psychiatry, 40, 733–742.
Pring Hermelin, L. B. (1993). Bottle, tulip and wineglass: Semanticand structural picture processing by savant artists. Journal ofChild Psychology and Psychiatry, 34, 1365–1385.
Pring, L., Hermelin, B., & Heavey, L. (1995). Savants, segments,art and autism. Journal of Child Psychology and Psychiatry, 36,1065–1076.
Rincover, A., & Koegel, R. L. (1975). Setting generality andstimulus control in autistic children. Journal of AppliedBehaviour Analysis, 8, 235–246.
Rinehart, N. J., Bradshaw, J. L., Moss, S. A., Brereton, A. V., &Tonge, B. J. (2000). Atypical interference of local detail onglobal processing in high-functioning autism and Asperger’sdisorder. Journal ofChildPsychology&Psychiatry, 41, 769–778.
Rinehart, N. J., Bradshaw, J. L., Moss, S. A., Brereton, A. V., &Tonge, B. J. (2001). A deficit in shifting attention present in high-functioning autismbut notAsperger’s disorder.Autism, 5, 67–80.
Ring, H. A., Baron-Cohen, S., Wheelwright, S., Williams, S. C.,Brammer, M., Andrew, C., & Bullmore, E. T. (1999). Cerebralcorrelates of preserved cognitive skills in autism: A functionalMRI study of embedded figures task performance. Brain, 122,1305–1315.
Robertson, L. C., & Lamb, M. R. (1991). Neuropsychologicalcontribution to theories of part/whole organization. CognitivePsychology, 23, 299–330.
Ronald, A., Happe, F., & Plomin, R. (2005). The genetic rela-tionship between individual differences in social and nonsocial
Happe and Frith
behaviours characteristic of autism. Developmental Science, 8,444–458.
Ropar, D., & Mitchell, P. (1999). Are individuals with autism andAsperger’s syndrome susceptible to visual illusions? Journal ofChild Psychology & Psychiatry, 40, 1283–1293.
Ropar, D., & Mitchell, P. (2001). Susceptibility to illusions andperformance on visuospatial tasks in individuals with autism.Journal of Child Psychology & Psychiatry, 42, 539–549.
Rouse, H., Donnelly, N., Hadwin, J. A., & Brown, T. (2004). Dochildren with autism perceive second-order relational features?The case of the Thatcher illusion. Journal of Child Psychology &Psychiatry, 45, 1246–1257.
Scheuffgen, K. (1998). Domain-general and domain-specific deficitsin autism and dyslexia. Unpublished Ph.D. thesis, Universityof London.
Scott, F. J., Brosnan, M. J., & Wheelwright, S. (submitted forpublication). Perception of illusions by people with autism: Isthere a low-level central coherence deficit?
Shah, A., & Frith, U. (1983). An islet of ability in autistic children:A research note. Journal of Child Psychology and Psychiatry,24, 613–620.
Shah, A., & Frith, U. (1993). Why do autistic individuals showsuperior performance on the Block Design task? Journal ofChild Psychology and Psychiatry, 34, 1351–1364.
Snowling, M., & Frith, U. (1986). Comprehension in ‘hyperlexic’readers. Journal of Experimental Child Psychology, 42, 392–415.
Spencer, J., O’Brien, J., Riggs, K., Braddick, O., Atkinson, J., &Wattam-Bell, J. (2000). Motion processing in autism: Evidencefor a dorsal stream deficiency. Neuroreport, 11, 2765–2767.
Stiles-Davis, J., Janowsky, J., Engel, M., & Nass, R. (1988).Drawing ability in four young children with congenital uni-lateral brain lesions. Neuropsychologia, 26, 359–371.
Stoecker, J. J., Colombo, J., Frick, J. E., & Allen, J. R. (1998).Long- and short-looking infants’ recognition of symmetrical
and asymmetrical forms. Journal of Experimental Child Psy-chology, 71, 63–78.
Suzuki, S., & Cavanagh, P. (1995). Facial organization blocksaccess to low-level features: An object inferiority effect. Jour-nal of Experimental Psychology: Human perception and Per-formance, 21, 901–913.
Tager-Flusberg, H. (1991). Semantic processing in the free recall ofautistic children: Further evidence for a cognitive deficit.British Journal of Developmental Psychology, 9, 417–430.
Teunisse, J.-P., Cools, A. R., van Spaendonck, K. P. M., Aerts,F. H., & Berger, H. J. (2001). Cognitive styles in high-func-tioning adolescents with autistic disorder. Journal of Autismand Developmental Disorders, 31, 55–66.
Teunisse, J. P., & de Gelder, B. (2003). Face processing in ado-lescents with autistic disorder: The inversion and compositeeffects. Brain & Cognition, 52, 285–294.
Uhlhaas, P. J., Silverstein, S. M., Phillips, W. A., & Lovell, P. G.(2004). Evidence for impaired visual context processing inschizotypy with thought disorder. Schizophrenia Research, 68,249–260.
Volberg, G., & Hubner, R. (2004). On the role of response conflictsand stimulus position for hemispheric differences in global/local processing: An ERP study. Neuropsychologia, 42,1805–1813.
Waiter, G. D., Williams, J. H., Murray, A. D., Gilchrist, A., Per-rett, D. I., & Whiten, A. (2005). Structural white matter defi-cits in high-functioning individuals with autistic spectrumdisorder: A voxel-based investigation. Neuroimage, 24,455–461.
Witkin, H. A., Dyk, R. B., Faterson, H. F., Goodenough, D. R., &Karp, S. K. (1962). Psychological differentiation. New York:Wiley.
Witkin, H. A., & Goodenough, D. R. (1981). Cognitive styles:Essence and origins. New York: International University Press.
Weak Coherence