The Profile of Memory Function in Children With Autism

Neuropsychology
Copyright 2006 by the American Psychological Association
2006, Vol. 20, No. 1, 21–29
0894-4105/06/$12.00
DOI: 10.1037/0894-4105.20.1.21
The Pro?le of Memory Function in Children With Autism
Diane L. Williams
Gerald Goldstein
University of Pittsburgh School of Medicine
Veterans Affairs Pittsburgh Healthcare System and
University of Pittsburgh
Nancy J. Minshew
University of Pittsburgh School of Medicine
A clinical memory test was administered to 38 high-functioning children with autism and 38 individually
matched normal controls, 8 –16 years of age. The resulting pro?le of memory abilities in the children with
autism was characterized by relatively poor memory for complex visual and verbal information and
spatial working memory with relatively intact associative learning ability, verbal working memory, and
recognition memory. A stepwise discriminant function analysis of the subtests found that the Finger
Windows subtest, a measure of spatial working memory, discriminated most accurately between the
autism and normal control groups. A principal components analysis indicated that the factor structure of
the subtests differed substantially between the children with autism and controls, suggesting differing
organizations of memory ability.
Keywords: autism, memory assessment, discriminant analysis, principal components analysis
The nature of memory function in autism has been under study
Inconsistency of ?ndings has always been problematic in autism
for decades. Memory has been characterized as both the cardinal
research. This problem is related to the high degree of variability
cognitive domain largely responsible for the clinical manifesta-
in the autism population, which is the result of developmental
tions of the disorder or as secondary to a more generalized cog-
differences and differences in cognitive levels among subject
nitive de?cit that transcends memory, such as executive dysfunc-
groups. However, a number of the ?ndings have been replicated
tion. In the 1970s and 1980s, the amnesia theory, one of the ?rst
across studies indicating that they are characteristic of memory
neurobehavioral models of autism, was based on the assumption
function in this population. Children with autism do not use
that memory dysfunction was the underlying basis for the social,
organizational strategies or context to support memory. For exam-
language, and behavioral abnormalities in autism (Boucher &
ple, children with autism remember randomly organized words as
Warrington, 1976). However, subsequent research refuted the am-
well as mentally retarded controls but do not demonstrate the
nesia theory (Minshew & Goldstein, 1993; Rumsey & Hamburger,
expected bene?t of semantic or syntactic organization (Frith,
1988). More recent models have proposed that the memory de?cits
1970a, 1970b; Fyffe & Prior, 1978; Hermelin & O’Connor, 1970).
are a re?ection of core de?cits in executive function (Bennetto,
Other studies have demonstrated that children with autism encode
Pennington, & Rogers, 1996; Russell, Jarrold, & Henry, 1996) or
the meaning of words and can bene?t from externally provided
of a basic de?cit in the processing of complex information (Min-
cues, but they do not spontaneously use semantic, syntactic, or
shew & Goldstein, 2001; Minshew, Goldstein, Muenz, & Payton,
temporal sequences effectively to facilitate retrieval of information
1992; Minshew & Payton, 1988). No agreement has been reached
(Tager-Flusberg, 1991). The memory de?cits reported by these
with respect to the role of memory functioning in the syndrome of
various studies do not appear to be the result of language de?cits,
autism, and the characterization of the status of memory abilities in
as groups were matched on language level. Signi?cant differences
autism is not adequate.
remained after covarying for language level and a de?cit was
present for temporal sequences as well as for syntactic and seman-
tically organized sequences.
Diane L. Williams, Department of Psychiatry, University of Pittsburgh
The complexity of the to-be-remembered material appears to be
School of Medicine; Gerald Goldstein, Research Service, Veterans Affairs
an important factor that in?uences the memory performance of
Pittsburgh Healthcare System, and Departments of Psychiatry and Psychol-
ogy, University of Pittsburgh; Nancy J. Minshew, Departments of Psychi-
children with autism. Fein et al. (1996) reported that memory
atry and Neurology, University of Pittsburgh School of Medicine.
function in autism was characterized by a dissociation between
This research was supported by National Institute of Child Health and
intact memory for material with low levels of structure and im-
Human Development (NICHD) Grant HD35469, National Institute of
paired memory for material with more complex levels of organi-
Neurological Disorders and Stroke Grant NS33355, and by an NICHD
zation; young children with autism had the least trouble with recall
Collaborative Program of Excellence in Autism. We also acknowledge the
of digits, more trouble with sentences, and the most dif?culty for
Medical Research Service, Department of Veterans Affairs, for support of
stories. Boucher (1981) reported that high-ability children with
this research. We thank Dan Bailey for assistance with data collection and
autism remembered signi?cantly less about recently experienced
data analysis.
events than normal age-matched and retarded age- and ability-
Correspondence concerning this article should be addressed to Nancy J.
matched controls. She proposed that, as a result, children with
Minshew, Department of Psychiatry, Autism Research Program, Webster
Hall, Suite 300, 3811 O’Hara Street, Pittsburgh, PA 15213. E-mail:
autism might encode less information from a complex stimulus
minshewnj@upmc.edu
such as a social interaction or conversation.
21

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22
WILLIAMS, GOLDSTEIN, AND MINSHEW
Visual memory for some types of material has been found to be
to de?ne the circuitry of the prefrontal cortex. Studies of working
an area of strength for children with autism but complexity of the
memory in individuals with autism have yielded inconsistent re-
stimuli appears to affect memory function in this modality as well.
sults. This inconsistency is probably related to variation in the way
Children with autism have been reported to perform as well as
in which working memory has been de?ned, the component of the
matched controls on a delayed response visual discrimination task
model studied, and the speci?c measures that have been used. In
(Prior & Chen, 1976); on a delayed match-to-sample visual mem-
addition, there may be a dissociation based on the type of infor-
ory task (Barth, Fein, & Waterhouse, 1995); and on recall of
mation that must be manipulated in working memory.
pictures of everyday scenes (de Gelder, Vroomen, & van der
The pattern of memory observed in children with autism can be
Heide, 1991), buildings (Boucher & Lewis, 1992), and shoes
conceptualized within the model of autism as a disorder of infor-
(Gepner, de Gelder, & de Schonen, 1996). However, results from
mation processing that disproportionably affects complex informa-
other studies indicate that, similar to ?ndings with verbal material,
tion processing abilities (Minshew & Goldstein, 1998). According
the visual memory of children with autism is susceptible to a lack
to information processing models of memory function, such as the
of response to organizational support and to the in?uence of
model of working memory proposed by Just and Carpenter (1992),
complexity of the stimuli, resulting in the stereotyped use of
the more complex the task and the information being processed,
simple patterns or rules regardless of the inherent organization of
the more taxed the resources of the memory system become. At the
the stimuli (Frith, 1970b). Several studies have reported that chil-
same time, whereas working memory capacity may be ?nite,
dren with autism exhibit de?cits in memory for visual sequences
processing large amounts of verbal information such as sequences
that are analogous to those reported for auditory memory (Boucher
of sentences is possible because the context facilitates processing
& Warrington, 1976; Minshew, Goldstein, & Siegel, 1997; Rapin,
by preactivating related concepts and schemas (Just & Carpenter,
1996); however, others have reported adequate visual memory for
1992). Storage capacity may be relatively intact, but complex
pictures of common objects arranged randomly or sequentially
information processing or the central executive (Baddeley, 1986)
(Hermelin & O’Connor, 1970; Prior & Chen, 1976). Children with
may be disproportionately impacted with implications for numer-
autism have been consistently reported to have dif?culty remem-
ous aspects of behavior. De?cits may emerge and become more
bering previously viewed faces (Boucher & Lewis, 1992; Boucher,
pronounced with increasing cognitive load (Minshew et al., 1997).
Lewis, & Collis, 1998; de Gelder et al., 1991; Gepner et al., 1996;
Problems in the memory domain occur because of the inadequacy
Klin et al., 1999), which are considered highly complex stimuli
of context facilitation and reduced concepts and schemas for
reliant on the formation of a prototype or speci?c organizational
access.
strategy for optimal recall.
The complexity of information is a dynamic concept that is
The construct of working memory, a domain of executive func-
relative to the age and general level of ability of the individual. A
tion, has received speci?c attention in investigations of the disor-
standard memory battery is a useful tool for examining functioning
der of autism. Studies of working memory in autism have largely
in varying aspects of memory within the same individuals. In this
used Baddeley’s (1986, 2003) model that consists of four compo-
way, the effect of complexity on memory functioning can be
nents called the central executive, the articulatory/phonological
compared in both auditory and visual modalities and in different
loop, the visuospatial scratchpad, and the episodic buffer. How-
components of the memory system without the confound of vari-
ever, tasks have not always been designed to clearly address the
ation in age and ability level that is introduced when trying to
individual components of the model and have more typically been
compare results from separate studies. In adults, the most widely
divided according to the cognitive domains of verbal and spatial
used battery of this type is the Wechsler Memory Scale—Third
skills. Verbal working memory has been considered by some
Edition (WMS–III; Wechsler, 1997). In two studies of older ado-
investigators to be a core cognitive de?cit in autism (Pennington et
lescents and adults with autism, the WMS–III was used to study
al., 1997). However, complexity of the stimuli also appears to be
the auditory and visual memory of high-functioning adolescents
an important consideration in this aspect of memory function.
and adults and group-matched normal controls (Minshew & Gold-
Direct measures of verbal working memory, ones that use only a
stein, 2001; Williams, Goldstein, & Minshew, 2005). Results
minimal processing load, have failed to con?rm a de?cit in this
indicated that basic associative memory abilities were intact, but
area in children with autism (Ozonoff & Strayer, 2001; Russell et
that the use of cognitive mediating strategies to support memory
al., 1996; Williams, Goldstein, Carpenter, & Minshew, 2005).
was impaired, and that memory impairments were progressively
Results from studies of spatial working memory in autism are less
worse as the complexity of the material increased in both the
clear. Children with autism have been reported to be unimpaired in
auditory and visual modalities. The adults with autism performed
spatial memory (when de?ned as recall of a location of a picture on
as well as the normal controls except when the subtests involved
a page; Klin et al., 1999), in a spatial memory-span task, and in a
social stimuli (e.g., memory for faces and memory for social
search task (Ozonoff & Strayer, 2001). However, children with
scenes) or spatial working memory—stimuli that were also high in
autism have been found to have a spatial working memory de?cit
information-processing demands.
on other behavioral tasks (Williams, Goldstein, Carpenter, & Min-
The purpose of the current study was to use a parallel instrument
shew, 2005). A study completed with adolescents and young adults
to the WMS–III, the Wide Range Assessment of Memory and
with autism found de?cits in spatial working memory as measured
Learning (WRAML; Sheslow & Adams, 1990), to evaluate mem-
by the oculomotor delayed response task, the classic paradigm for
ory in children with autism with the aim of determining whether a
assessing spatial working memory (Minshew, Luna, & Sweeney,
similar pattern of memory functioning was seen in autism at an
1999). This task assesses the capacity for making a saccadic eye
earlier developmental stage. We were interested in examining
movement to the location of a target previously presented in the
several facets of memory processing in a single group of children
periphery and has been widely used in primate and human research
with autism using stimuli that varied by level of complexity as well

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MEMORY PROFILE
23
as modality of presentation (auditory or visual). In addition, we
ments in social interaction and restricted patterns of behavior but without
wanted to investigate the use of strategies to facilitate memory
impairments in language/communication development, cognition, or adap-
functioning. Baddeley’s (1986, 2003) components of working
tive behavior were considered to have Asperger’s Disorder and were
memory were also considered because there are tasks that relate to
excluded from the study. Potential participants were also excluded if found
to have evidence of an associated neurologic, genetic, infectious, or met-
the central executive, the articulatory loop, the visuospatial
abolic disorder, such as tuberous sclerosis, fragile X syndrome, or cyto-
scratchpad, and the episodic buffer. That is, tests of associative
megalovirus. Exclusions were based on neurologic history and examina-
verbal memory, spatial memory, and prose recall were used. The
tion, physical examination, chromosomal analysis, and, if indicated, met-
central executive would be involved in several of the more com-
abolic testing. Two thirds of the participants with autism (25 of 38) were
plex tasks such as those involving recall of stories and complex
taking medication at the time of the study. These medications were for the
pictorial material. Although the opportunity was available to con-
management of anxiety, attention, sleep, and restricted–repetitive behav-
?rm our earlier ?nding (Williams, Goldstein, Carpenter, & Min-
iors, conditions that are often part of autism.
shew, 2005) of impaired spatial relative to verbal working memory
Neuropsychiatrically normal, medically healthy control participants
in autism, we note that there is a persistent problem of equating
were recruited from community volunteers. Potential control participants
verbal and spatial tasks for dif?culty level.
were screened by questionnaire, telephone, face-to-face interview, and
observation during screening psychometric tests. Exclusionary criteria,
evaluated through these procedures, included a history or evidence of birth
Method
or developmental abnormalities; acquired brain injury; poor school atten-
dance; a learning or language disability; a current or past history of
Participants
psychiatric or neurologic disorder; a medical disorder with implications for
The participants for this study consisted of 38 high-functioning children
the central nervous system or requiring regular medication usage; or a
with autism and 38 individually matched control participants between 8
family history in ?rst-degree relatives of autism, developmental cognitive
and 16 years of age. All participants had Wechsler Full Scale and Verbal
disorder, learning disability, mood disorder, anxiety disorder, alcoholism,
IQ scores greater than 80. Demographic characteristics of the two groups
or other neuropsychiatric disorders thought to have a genetic or familial
are provided in Table 1. We determined socioeconomic status using a
component.
modi?cation of the Hollingshead procedure (Hollingshead, 1957). The two
participant groups did not differ signi?cantly with regard to age, Verbal IQ,
Materials
Performance IQ, Full Scale IQ, race, or socioeconomic status.
The University of Pittsburgh Medical Center Institutional Review Board
The WRAML (Sheslow & Adams, 1990) was designed to be an inclu-
approved this study. Procedures were fully explained to all participants and
sive memory battery that is normed for children between 5 and 17 years of
to their parents or guardians. Written informed consent was obtained from
age. An advantage of using a clinical test such as the WRAML is that it
participants and their parents or guardians. All participants were recruited
provides a number of memory tasks that are all based on a common
through the Subject Core of the University of Pittsburgh Collaborative
normative group and that have known intercorrelations and factor structure.
Program of Excellence in Autism funded by the National Institute of Child
This allows for meaningful comparison across tasks both within and
Health and Human Development.
between groups.
For the participants with autism, con?rmation of their diagnosis was
The WRAML consists of nine subtests that in many ways resemble the
established through obtained scores on two structured research diagnostic
WMS–III subtests. However, rather than being divided into visual and
instruments—the Autism Diagnostic Interview (Le Couteur et al., 1989;
auditory domains, it is divided into visual, auditory, and learning domains.
Lord, Rutter, & Le Couteur, 1994) and the Autism Diagnostic Observation
Numerous scores may be obtained, including standard scores for each of
Schedule (Lord et al., 1989)—and expert clinical evaluation in accordance
the subtests and index scores for the three domains and general memory.
with accepted clinical descriptions of high-functioning individuals with
Separate scores for delayed recall and recognition memory are also avail-
autism (Minshew, 1996; Minshew & Payton, 1988; Rapin, 1991; Rutter &
able. Conversion of the raw scores to standard scores allows for production
Schopler, 1987). Participants included in this group met or exceeded the
of a pro?le from which relative levels of performance on the various
cutoffs for autism on both the Autism Diagnostic Interview and Autism
subtests can be directly compared. Similar to the WMS–III, the WRAML
Diagnostic Observation Schedule and had positive evidence of past and
contains tests involving immediate memory span, story recall, and asso-
current language/communication impairments. Individuals with impair-
ciative learning. The Verbal Memory scale consists of a Number/Letter
Table 1
Demographic Data
Autism
Control
group
group
Variable
M
SD
M
SD
t
df
p
Age in years
11.68
2.46
12.16
2.19
0.89
74
.38
Years of education
5.90
2.48
5.90
2.06
0.01
58
.99
SESa
2.88
1.37
3.36
0.86
1.65
57
.11
VIQ
106.42
15.97
107.34
8.09
0.32
74
.75
PIQ
100.55
14.19
105.95
10.43
1.89
74
.06
FIQ
103.82
14.29
107.18
9.37
1.22
74
.23
Note.
SES
socioeconomic status; VIQ
Verbal IQ scores; PIQ
Performance IQ scores; FIQ
Full-Scale
IQ scores.
a Mean is between business managers and administrative personnel range.

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24
WILLIAMS, GOLDSTEIN, AND MINSHEW
sequence memory task in which the child repeats a random mix of audi-
exceeded the minimal Verbal and Full Scale IQ scores required for admis-
torally presented numbers and letters, a Sentence Memory task in which the
sion to the study. Means and standard deviations for the two groups on the
child repeats progressively longer meaningful sentences, and a Story Recall
individual WISC–III subtests are provided in Table 2. The WRAML was
task in which the child recalls details of two short stories that were read
administered according to instructions contained in the administration
aloud. The Visual Memory scale assesses recall of geometric designs,
manual (Sheslow & Adams, 1990) after the WISC–III at a separate testing
picture scenes, and sequences. The Design Memory subtest requires the
session. Trained technicians under the supervision of a professional psy-
child to draw one of four designs after a 10-s delay. In the Picture Memory
chologist administered both tests. Measures used were the scaled scores
subtest, the child views a complex meaningful scene, then looks at a
from the individual subtests, delayed recall subtest scores, and the Story
second, similar scene and indicates what is now different. The Finger
Memory Recognition score.
Windows task requires the participant to recall the sequential placement by
the examiner of a pencil into a series of holes placed in a plastic card. It is
Data Analysis
considered a measure of spatial working memory and is comparable with
the Spatial Span subtest of the WMS–III. The Learning scale consists of a
The data were initially analyzed with individual t tests comparing the
word list recall task, a sound symbol association task, and a design location
means of the autism and control groups on all scores. To evaluate classi-
recall task. The WRAML subtests were meant to vary in meaningfulness of
?catory accuracy, we performed discriminant function analyses using the
content. In a review of the test, Miller, Petrie, Bigler, and Adams (2003)
nine immediate memory subtests as a multivariate combination. All vari-
pointed out that meaningfulness refers both to task complexity and rele-
ables were entered in the initial analyses to determine overall level of
vance to everyday life. Thus, there are tests of simple associative memory
signi?cance; if statistical signi?cance was obtained ( p
.05), stepwise
with little meaningful content and tasks such as story or picture recall that
analyses were planned. Default F to enter and an F to remove options were
are quite complex.
used in the stepwise analysis, followed by application of a more liberal
The WRAML was normed on a group of 2,363 children on the basis of
tolerance test (F
1.00 and F
0.95). The more liberal tolerance test was
a strati?ed model that re?ected national demographic data (Sheslow &
used to determine the order of entry of the subtests beyond what was
Adams, 1990). The subtests and composite indices demonstrate high in-
entered on the basis of a conservative tolerance test. This procedure was
ternal consistency reliability according to item separation statistics (rang-
accomplished for the purpose of evaluating the distinction previously noted
ing from .99 to 1.0), person separation statistics (ranging from .70 to .94),
between intact associative memory and relatively poorer complex memory
coef?cient alphas for the nine individual subtests (ranging from .78 to .90),
in individuals with high-functioning autism, because the WRAML contains
and median coef?cient alphas for the Verbal Memory Index, the Visual
measures of both types. To determine whether the organization of abilities
Memory Index, and the Learning Index (.93, .90, and .91, respectively).
assessed by the WRAML was the same in the autism group as in the
Criterion-referenced validity for the WRAML has been established by
control group, we performed a preliminary principal components analysis
examining the relationship between obtained scores on the WRAML and
with Varimax rotation for each group. Factor structures were compared
obtained scores on other standardized assessments of memory in children.
with each other and with the principal components analysis contained in
The results of these studies as presented in the WRAML administration
the WRAML manual.
manual range from a high degree of relationship (.90 correlation for the
WRAML Verbal Memory Index and the McCarthy Scales of Children’s
Ability Memory Index; .80 correlation for the WRAML General Memory
Results
Index and the Stanford Binet Memory Index) to lower degrees of relation-
ship (.10 correlation for the WRAML Learning Memory Index and the
Individual Subtest Comparisons
McCarthy Memory Index) (Sheslow & Adams, 1990). WRAML indices
The t-test results comparing the autism and control groups on
are positively correlated with academic achievement measures of reading,
the WRAML scales are presented in Table 3. Signi?cant ( p
.05)
spelling, and arithmetic (Miller et al., 2003).
differences were found for the Sentence Memory, Story Memory,
Finger Windows, Design Memory, and Picture Memory subtests.
Procedure
Signi?cant differences were not found for the Number/Letter,
All participants received the Wechsler Intelligence Scale for Children—
Verbal Learning, Sound Symbol, and Visual Learning subtests.
Third Edition (WISC–III; Wechsler, 1991) to determine whether they
Signi?cant differences were all associated with medium effect
Table 2
Means and Standard Deviations for the WISC–III Subtests
Autism group
Control group
Subtest
M
SD
M
SD
t
df
p
d
Information
13.05
2.48
11.68
2.29
2.59
74
.01
0.57
Similarities
12.08
2.79
11.18
1.86
1.64
74
.10
0.38
Arithmetic
11.13
4.28
11.68
2.62
0.68
74
.50
0.15
Vocabulary
11.34
3.20
11.03
2.01
0.52
74
.61
0.12
Comprehension
7.45
3.75
10.58
2.07
4.51
74
.00
1.03
Digit Span
10.39
3.47
11.03
2.84
0.87
74
.39
0.20
Picture Completion
10.42
2.75
11.18
2.29
1.32
74
.19
0.30
Coding
8.37
3.82
10.74
2.82
3.08
74
.003
0.71
Picture Arrangement
9.71
3.09
10.55
2.88
1.23
74
.22
0.28
Block Design
11.66
3.83
11.84
3.25
0.23
74
.82
0.05
Object Assembly
9.95
3.38
9.92
2.12
0.04
74
.97
0.01
Symbol Search
10.12
4.21
12.25
2.35
2.55
60
.01
0.62
Note.
WISC–III
Wechsler Intelligence Scale for Children—Third Edition.

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MEMORY PROFILE
25
Table 3
Means and Standard Deviations for the WRAML Subtests
Autism group
Control group
Subtest
M
SD
M
SD
ta
p
d
Finger Windows
8.61
3.00
10.89
3.35
2.86
.002
0.72
Design Memory
8.32
3.16
10.13
2.56
2.76
.01
0.63
Picture Memory
8.63
2.83
9.92
2.66
2.05
.04
0.47
Number/Letter
8.61
3.33
9.26
2.61
0.96
.34
0.22
Sentence Memory
8.87
3.54
10.39
2.50
2.17
.03
0.50
Story Memory
8.89
3.51
10.63
2.84
2.37
.02
0.55
Verbal Learning
10.39
3.51
11.34
2.69
1.32
.19
0.30
Sound Symbol
10.87
3.02
10.76
2.63
0.16
.87
0.04
Visual Learning
10.68
3.50
11.39
2.62
1.00
.32
0.23
Note.
WRAML
Wide Range Assessment of Memory and Learning. a df
74.
sizes (Cohen, 1988). The pattern of differences between the autism
also in the way in which those abilities are organized. The prin-
and control groups was characterized by the autism group’s worse
cipal components analysis for children age 9 years and older that
performance on measures of visual memory, verbal memory in-
appears in the WRAML manual involves three factors (Table 7.11
volving syntactic and discourse elements, and spatial working
in the manual). The ?rst of these, called Visual, receives its highest
memory. The groups did not differ on measures of associative
loadings from the Picture Memory and Design Memory subtests,
memory and immediate memory span.
with slightly lower loadings from Finger Windows and Visual
Learning. The second factor, called Verbal, receives high loadings
Discriminant Function Analyses
from Sentence Memory and Number/Letter Memory. The third
factor, called Learning, receives high loadings from the Verbal
For the direct method discriminant function analysis, a Wilks’
Learning, Story Memory, and Sound Symbol subtests.
lambda ( ) of .78 was obtained, which is statistically signi?cant
The principal components analysis with Varimax rotation for
( p
.05). The classi?cation matrix is contained in Table 4.
our control group is presented in Table 5. Although the application
Of the cases, 68.4% were correctly classi?ed. Kappa was equal
of Kaiser’s Rule produced a four-factor solution, we also requested
to .37 ( p
.001), which is statistically signi?cant but falls into the
a three-factor solution for purposes of comparison with the prin-
“poor agreement beyond chance” Landis and Koch category
cipal components analysis in the WRAML manual. The four-factor
(Fleiss, 1981). Using default options, only Finger Windows was
solution did not differ substantially from the three-factor solution,
entered in the stepwise analysis. When a more liberal tolerance test
as the fourth factor only received a high loading from Finger
was used (F to enter
1.00; F to remove
0.95), Finger
Windows; therefore, we refer to the three-factor solution for our
Windows, Design Memory, Picture Memory, and Sound Symbol
comparisons. The ?rst factor of the three-factor solution received
were entered. In the case of Sound Symbol, the mean score for the
high loadings from Design Memory, Visual Learning, and Sound
autism group was slightly better than that of the control group.
Symbol. It therefore resembles the WRAML manual Visual factor
Thus, the WRAML pro?le as a whole produced a statistically
with high loadings from two of the four visual subtests. The second
signi?cant but not a highly accurate classi?cation of autism and
factor received high loadings from Sentence Memory and Number/
control participants. However, there were numerous signi?cant
Letter Memory; these are the same subtests that constituted the
group differences for the individual subtests. The most powerful
Verbal factor from the WRAML manual. The third factor received
discriminator was Finger Windows, a test that appears to assess
high loadings from Verbal Learning, Story Memory, and Picture
spatial working memory.
The Principal Components Analysis
Table 5
Differences in memory between children with autism and typ-
Varimax Rotated Component Matrix for the Control Group
ically developing children may not only lie in separate abilities but
1
2
3
Subtest
Visual
Verbal
Learning
4
Table 4
Classi?cation Matrix for Discriminant Function Analysis of the
Design Memorya
.83
.12
.19
.00
WRAML Subtests
Visual Learninga
.83
.00
.16
.27
Sound Symbol
.66
.00
.00
.00
Predicted group membership
Number/Lettera
.24
.87
.00
.00
Sentence Memorya
.00
.82
.23
.00
Group
Autism
Control
Total
Story Memorya
.15
.17
.78
.11
Verbal Learninga
.00
.13
.77
.25
Autism
25
13
38
Picture Memory
.17
.32
.58
.22
Control
11
27
38
Finger Windows
.12
.10
.00
.48
Note.
Of the cases, 68.4% were correctly classi?ed. WRAML
Wide
a Matches principal components analysis from the Wide Range Assessment
Range Assessment of Memory and Learning.
of Memory and Learning manual.

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26
WILLIAMS, GOLDSTEIN, AND MINSHEW
Memory—two of the three subtests that had high loadings on the
immediate recall and 11.16 for recognition, whereas the controls
Learning factor from the WRAML manual. Clearly the results
obtained corresponding mean scores of 10.63 and 12.05. Both
obtained from the small sample used in our study differed some-
groups did better on recognition than on free recall, with only a
what from the factor solution obtained from the larger normative
minor amount of improvement suggesting that the children with
sample for the WRAML, but, with some exceptions, our control
autism did not have a de?cit in retrieval. The difference between
group produced what can reasonably be interpreted as Visual,
the groups was in the initial encoding process. In summary, the
Verbal, and Learning factors.
autism group showed a difference in delayed recall for complex
This solution is in sharp contrast to what was found for the
thematic verbal material and did not show a speci?c retrieval
autism group. The rotated factor matrix is presented in Table 6.
de?cit.
Applying Kaiser’s Rule, two factors were extracted. The ?rst one
received high loadings from all of the subtests except for Picture
Discussion
Memory and Story Memory. The second factor received high
loadings only from those two subtests. This pattern shows essen-
The administration of the WRAML yielded a pro?le of memory
tially no resemblance to the Visual, Verbal, and Learning structure
abilities in children with autism that was substantially different
found in the WRAML manual and the control group from this
from the pro?le found in a control group of typically developing
study. It is particularly interesting to note that in the WRAML
children. The memory pro?le of the autism group was character-
manual factor analysis, Picture Memory and Story Memory loaded
ized by relatively poor memory for both complex visual (Design
on different factors, whereas they loaded on the same factor for our
Memory and Picture Memory) and complex verbal (Sentence
group with autism. This might be the result of an organization that
Memory and Story Memory) stimuli, with relatively intact asso-
involves thematic nonsocial and social components to explain the
ciative learning ability (Sound Symbol), verbal working memory
factor structure for the autism group. Whereas these two subtests
(Number/Letter), and recognition memory (Story Memory recog-
also loaded on the same factor in the current study’s control group,
nition score). Spatial working memory of the children with autism
Verbal Learning loaded on the same factor as well, making it less
(Finger Windows) was also impaired relative to the control group;
of a factor speci?cally associated with social thematic content.
however, spatial memory as de?ned as memory for location (Vi-
When we forced a two-factor solution for the normal control
sual Learning) was not. Delayed recall of the children with autism
group, the pattern was quite different from what was found for the
was not generally different than that of the matched controls, with
autism group. All of the subtests had high loadings on the ?rst
the exception of thematic verbal material as assessed by recall of
factor except for Sentence Memory and Number/Letter Memory,
stories. Principal components analysis of the WRAML subtests
both of which received high loadings on the second factor. Thus,
indicated a very different ability structure from that demonstrated
in the two-factor solution for the control group, there was no
by the typically developing control group and from that of the
suggestion of a distinct factor for subtests with social thematic
normative sample for the WRAML.
content.
The memory pro?le for the children with autism as measured by
the WRAML was similar but not identical to that for our group of
Delayed Recall and Recognition Memory
adults with autism as measured by the WMS–III (Williams, Gold-
stein, & Minshew, 2005). Both the adults and the children with
The WRAML contains 20 – 40 min delayed recall procedures for
autism performed signi?cantly worse than the normal control
Verbal Learning, Story Memory, Sound Symbol, and Visual
group on complex visual memory tasks and the spatial working
Learning subtests, and there is also a recognition memory proce-
memory task. No difference was obtained for the verbal working
dure for the Story Memory subtest. Group comparisons are con-
memory task or verbal memory list learning in either the children
tained in Table 7.
or adults with autism. However, the children with autism differed
The only signi?cant difference was for Story Memory but only
from their matched controls on sentence and story memory tasks,
for delayed recall not the recognition measure. A comparison of
whereas no difference was found for the adults with autism com-
the discrepancy between immediate and recognition memory
pared with controls on a similar task. Sentence and story memory
scores for the Story Memory showed little difference between the
tasks are affected by language development, which may explain
groups. The autism group obtained a mean score of 8.89 for
the difference in performance on this task between the adults and
children with autism. Story memory is enhanced by the develop-
ment of a “story grammar” or the understanding of the basic
Table 6
structure of a story (Mandler & Johnson, 1977; Thorndyke, 1977).
Varimax Rotated Component Matrix for the Autism Group
This is a skill that the children with autism did not appear to have
but that appeared to be present in the adult group with autism and
Subtest
1
2
in the children with typical development. The conclusion that the
Number/Letter
.85
.00
children with autism lacked the memory support provided by a
Verbal Learning
.79
.28
story grammar is supported by the relative dif?culty that they had
Finger Windows
.79
.13
on the delayed story memory task. It is possible that adults with
Sentence Memory
.73
.19
autism have the support of a story grammar because they have
Design Memory
.72
.00
Visual Learning
.65
.12
been taught it. Alternatively, it could be a skill that is acquired
Sound Symbol
.52
.20
through a combination of natural brain development and cognitive
Story Memory
.25
.80
maturation during the second decade of life and exposure to
Picture Memory
.00
.82
written language through reading.

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MEMORY PROFILE
27
Table 7
Means and Standard Deviations for the WRAML Delayed and Recognition Memory Subtests
Autism group
Control group
Subtest
M
SD
M
SD
t
df
p
d
Delayed Verbal Memory
9.34
2.84
10.29
2.65
1.50
74
.14
0.35
Delayed Story Memory
10.86
5.13
13.63
4.24
2.56
73
.01
0.58
Delayed Sound Symbol
8.05
2.54
8.29
2.53
0.41
74
.68
0.07
Delayed Visual Learning
9.53
3.17
9.89
2.74
0.54
74
.59
0.12
Story Memory Recognition
10.88
3.04
12.15
1.67
2.12
66
.04
0.52
Note.
WRAML
Wide Range Assessment of Memory and Learning.
A comparison of the results from our study with the experimen-
recognize items that were seen previously but must also detect
tal literature on memory in autism reveals numerous consistencies.
novel items. High-functioning children with autism have been
As expected, our child participants with autism had intact memory
reported to have intact visual memory on delayed-matching-to-
for recall of lists of random words as has been reported by prior
sample visual-recognition memory tasks when compared with
studies (Frith, 1970a, 1970b; Hermelin & O’Connor, 1970; Min-
children with developmental language disorder (Barth et al., 1995).
shew & Goldstein, 1993). The children with autism also had strong
The additional processing requirements of the Picture Memory
associative learning as was reported earlier (Boucher & War-
subtest appear to have decreased the memory performance of the
rington, 1976). They performed the visual learning task, which
children with autism relative to the performance of the control
involved recalling object locations, as well as the typical children.
group.
This task is very similar to the Spatial Memory task of the
The conceptualization of memory de?cit as a consequence of
Kaufman Assessment Battery for Children (Kaufman & Kaufman,
dif?culties with complex information processing now appears to
1983), for which Klin et al. (1999) found no group differences
be supported in both children and adults with autism. Con?rmation
among their children with autism, pervasive developmental disor-
of this theory requires both negative evidence in the form of intact
der, and non-pervasive-developmental disorders. Consistent with
simple abilities accompanied by impairment in complex areas such
Fein et al. (1996), our group of children with autism had relative
as story recall or recall of detailed pictorial material. Both types
dif?culty with recall of sentences and stories. These results also
were present here. Although the limbic-prefrontal theory of Ben-
correspond to the pattern of increasing memory de?cits with
Shalom (2003) remains a possibility, there is growing evidence
increasing stimulus complexity reported for older adolescents and
from functional neuroimaging that the actual dif?culty in autism
adults with autism (Minshew et al., 1997; Minshew & Goldstein,
lies in connectivity between perceptual and memory regions and
2001). Verbal working memory as measured by the number–letter
differing information processing strategies (Just, Cherkassky,
sequence task was intact—a result supported by a small number of
Keller, & Minshew, 2004; Koshino et al., 2005).
previous studies (Ozonoff & Strayer, 2001; Russell et al., 1996;
There are several limitations to this research that should be
Williams, Goldstein, Carpenter, & Minshew, 2005). In contrast,
addressed before reaching more de?nitive conclusions. First, and
spatial working memory as assessed by Finger Windows was
most obviously, autism is a rare disorder, and it is dif?cult to
relatively poorer when compared with the performance of the
obtain samples large enough to complete formal psychometric
control group. This result is consistent with prior reports of im-
studies involving epidemiologically accurate strati?ed sampling
paired performance on the oculomotor delayed response paradigm
and to support advanced multivariate statistics with fully adequate
for the assessment of spatial working memory in adolescents and
samples. Second, when no behavioral differences between the
adults with autism (Minshew et al., 1999). Performance on the
autism and control group were seen, we do not know whether the
oculomotor delayed response task has also been linked to de-
children with autism were using the same cognitive strategies as
creased activation in prefrontal and posterior cingulate circuitry
the typically developing control children. Recent functional neu-
during functional MRI (Luna et al., 2002). As discussed earlier,
roimaging results with high-functioning adults with autism have
Finger Windows was entered ?rst in the stepwise discriminant
raised the possibility that behavioral similarities may actually be
analysis indicating that it strongly discriminated between the au-
arising from differences in cognitive strategies (Just et al., 2004;
tism and control groups.
Koshino et al., 2005). Third, the WRAML clinical measures are
As expected, our group of children with autism exhibited more
relatively brief samples of each behavior; therefore, these results
dif?culty with the recall of complex visual stimuli than the
need to be further investigated by the completion of more detailed
matched control children. The Design Memory task from the
experimental memory procedures. Fourth, although several studies
WRAML is similar to the Rey–Osterrieth Complex Figure task
have indicated an apparent de?cit in spatial working memory
that has been used in a number of studies demonstrating that
relative to verbal working memory, it has been dif?cult to develop
high-functioning adults with autism have dif?culty with immediate
verbal and spatial tasks that are of equal dif?culty level; this must
and delayed recall of complex ?gures (Minshew et al., 1992;
be done before this distinction can be more de?nitively
Minshew & Goldstein, 2001; Rumsey & Hamburger, 1990). The
established.
Picture Memory subtest is a nonmatching-to-sample task without a
In interpreting the ?ndings of the principal components analysis,
delay. It is particularly challenging because the child must not only
it should be pointed out that attempts by other groups of research-

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28
WILLIAMS, GOLDSTEIN, AND MINSHEW
ers to factor analyze the WRAML did not reach the same factor
Dewey, D., Kaplan, B. J., Crawford, S. G., & Fisher, G. C. (1998).
solution as the one reported in the manual (Burton, Mittenberg,
Predictive accuracy of the Wide Range Assessment of Memory and
Gold, & Drabman, 1999; Dewey, Kaplan, Crawford, & Fisher,
Learning in children with attention de?cit hyperactivity disorder and
1998). The major difference seems to involve the failure of the
reading dif?culties. Developmental Neuropsychology, 19, 173–189.
original analysis to extract an attention/concentration factor. Al-
Fein, D., Dunn, M. A., Allen, D. M., Aram, R., Hall, N., Morris, R., &
though that may be the case, the factor structure found in the
Wilson, B. C. (1996). Neuropsychological and language ?ndings. In I.
autism group does not resemble those found in analyses that
Rapin (Ed.), Preschool children with inadequate communication: De-
extracted an attention/concentration factor. For example, the atten-
velopmental language disorder, autism, low IQ (pp. 123–154). London:
Mac Keith Press.
tion/concentration factor shown in Burton et al.’s (1999) study
Fleiss, J. L. (1981). Statistical methods for rates and proportions (2nd ed.).
contained high loadings only from Number/Letter Sequencing and
New York: Wiley.
Sentence Memory, whereas the autism group did not produce a
Frith, U. (1970a). Studies in pattern detection in normal and autistic
factor that was close to that pattern.
children: I. Immediate recall of auditory sequences. Journal of Abnormal
From a clinical perspective, the pro?le of memory strengths and
Psychology, 76, 413– 420.
weaknesses supports Boucher’s (1981) suggestion that children
Frith, U. (1970b). Studies in pattern detection in normal and autistic
with autism acquire less information from complex stimuli, includ-
children: II. Reproduction and production of color sequences. Journal of
ing complex scenes, sentences, and stories. This difference in
Experimental Child Psychology, 10, 120 –135.
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functioning in social communication and problem solving. This is
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not to suggest that the relative weaknesses in memory functioning
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Gepner, B., de Gelder, B., & de Schonen, S. (1996). Face processing in
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autistics: Evidence for a generalized de?cit? Child Neuropsychology, 2,
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Hollingshead, A. B. (1957). Two-factor index of social position. New
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Just, M. A., & Carpenter, P. A. (1992). A capacity theory of comprehen-
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Just, M. A., Cherkassky, V. L., Keller, T. A., & Minshew, N. J. (2004).
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Accepted May 23, 2005

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