Content uploaded by Sabine Huemer
Author content
All content in this area was uploaded by Sabine Huemer on Feb 10, 2017
Content may be subject to copyright.
Content uploaded by Sabine Huemer
Author content
All content in this area was uploaded by Sabine Huemer on Feb 10, 2017
Content may be subject to copyright.
PSYCHOLOGY AND COGNITIVE SCIENCES
Open Journal http://dx.doi.org/10.17140/PCSOJ-3-118
Psychol Cogn Sci Open J
ISSN 2380-727X
Memory in Autism: A Case of Remembering
Versus Knowing
Sabine Huemer, PhD*
Department of Psychology, Loyola Marymount University, 1 LMU Drive, Los Angeles, CA
90045, USA
*Corresponding author
Sabine Huemer, PhD
Visiting Assistant Professor
Department of Psychology
Loyola Marymount University
1 LMU Drive, Los Angeles
CA 90045, USA
E-mail: shuemer@lmu.edu;
Sabine.Huemer@lmu.edu
Article History
Received: October 30th, 2016
Accepted: December 5th, 2016
Published: December 6th, 2016
Citation
Huemer S. Memory in autism: A case
of remembering versus knowing.
Psychol Cogn Sci Open J. 2016; 3(1):
1-5. doi: 10.17140/PCSOJ-3-118
Copyright
©2016 Huemer S. This is an open
access article distributed under the
Creative Commons Attribution 4.0
International License (CC BY 4.0),
which permits unrestricted use,
distribution, and reproduction in
any medium, provided the original
work is properly cited.
Volume 3 : Issue 1
Article Ref. #: 1000PCSOJ3118
Mini Review
Page 1
According to the Diagnostic and Statistical Manual Fifth Edition, the DSM-5,1 autism
spectrum disorder (ASD) is a neurodevelopmental disorder characterized by persistent social
communication decits and repetitive patterns of behavior including intense preoccupations
and inexible adherence to routines. ASD may occur with or without accompanying intellec-
tual impairment and the severity of the disorder may uctuate over time. Previously, an ASD
diagnosis based on the Diagnostic and Statistical Manual Fourth Edition (DSM-IV) fell into
one of 5 subtypes, most prominently, Asperger’s syndrome and autism, diagnoses that indicat-
ed a generally higher (Asperger’s) or lower level of functioning (autism). This brief report at-
tempts to review literature on memory in ASD with a special focus on the discrepancy between
an intact, at times, even extraordinary memory for large amounts of factual information and an
often impaired memory for autobiographical information. A look at memory patterns in ASD
may be helpful in understanding learning differences and aid in the customization of targeted
intervention strategies.
Tulving2,3 divides human memory into 2 distinct systems that are open to conscious
awareness: The semantic system stores timeless facts available mostly upon cued recall recog-
nition, while the episodic system relies on an individual’s ability to put stored memories into
a spatio-temporal and self-referential context upon free recall.4 The Remember/Know (R/K)
procedure3 is used in recognition tasks to study both memory systems. Participants are asked to
study a list of words, and then have to respond whether they remember the episode of having
seen the word (R), or if they merely know (K) the word without the recollection of the specic
episode.
Early observational studies found that individuals with classic autism and Asperger’s
often possess extraordinary rote memory skills and are able to memorize large amount of fac-
tual information.5,6 Experimental studies on memory in ASD reveal a pattern of unimpaired
memory span alongside impaired free recall.7,8 When asked to recall a sequence of dot locations
in order, Bowler et al9 revealed impairments in non-verbal short-term serial order memory in
adults with ASD as compared to typical individuals. Together with parallel ndings using ver-
bal material,10 these results indicate that order processing appears to be a cross-domain decit
in ASD.
Free recall and the ability of mental time travel2 have been related to the comprehen-
sion of a temporally extended self,11,12 the understanding that the “I” we experience now is the
same as the “I” from memories past, and episodic future thinking,13 the ability to project oneself
into plausible future situations. Zelazo et al14,15 have shown that children with ASD have prob-
lems with this type of episodic remembering in tasks involving ‘if-then’ rules.15,16 Later studies
revealed the neural correlates of R/K discrepancies in ASD: episodic recognition involving the
recollection of contextual information (R), which is impaired in ASD, shows to be mediated
by hippocampal processes while familiarity based recognition (K), which is intact in ASD, is
mediated by perirhinal processes.17-19
Free recall and episodic memory impairments have been associated with decits in
PSYCHOLOGY AND COGNITIVE SCIENCES
Open Journal http://dx.doi.org/10.17140/PCSOJ-3-118
Psychol Cogn Sci Open J
ISSN 2380-727X
Page 2
theory of mind (ToM),20 the understanding of others beliefs and
perspectives, an ability that has shown to be delayed or impaired
in ASD.21,22 In order to have episodic memories, a person needs
to be able to form a metarepresentation of an episode, i.e. they
must be able to understand their own memory of an event as a
representation of the actual event.23 These metarepresentations
help a person to hold a true and false understanding of an event
which is necessary in false-belief tasks testing ToM. Based on
problems with ToM in ASD and the association of ToM with epi-
sodic memory decits, Bowler, Gardiner and Grice24 predicted
and found that participants with Asperger’s had lower R scores
on recognition tasks using the standard R/K procedure. How-
ever, both control group and Asperger individuals yielded more
R responses of high-frequency than low-frequency words. Both
groups also show reduced R but not K responses when atten-
tion during the encoding phase was divided.25 This qualitative,
but not quantitative, similarity between groups indicates that
individuals with Asperger’s can reconstitute some of the spatio-
temporal and self-referential context needed in episodic memory
tasks.
Lind et al26 examined 20 high functioning elementary
school children with ASD and compared them to 20 neurotypi-
cal controls to probe the possibility of interdependent atypical
cognitive development and behavior on series of tasks. The ASD
group exhibited impairments in spatial navigation, episodic
memory, episodic future thinking, and central coherence but not
ToM and relational memory as compared to controls. ToM was
tested on a version of the “animations” task27 which is sensitive
to ToM impairments in high-functioning individuals with ASD
contrary to the more traditional “false belief tasks”.23 Interest-
ingly, spatial navigation as tested on the computer-simulated
“memory island” task was signicantly negatively correlated to
repetitive behaviors in the ASD group.
In a recent functional magnetic resonance imaging or
functional MRI (fMRI) study in which participants listened to
four categories of names including their own rst names, (Hue-
mer S et al unpublished data, 2016) found that individuals with
ASD with high verbal ability, just like neurotypical controls, ac-
tivated right hippocampal processes when hearing their own rst
name, while individuals with ASD with low verbal ability scores
activated left thalamic processes associated with the memoriza-
tion of new events.28 Since perirhinal areas receive afferents from
the nucleus reuniens of the thalamus, these ndings indicate that
individuals with ASD who have lower verbal ability “know”
their name like a recently learned fact whereas individuals with
ASD with high verbal ability, who often nd themselves on the
higher functioning end of the autism spectrum, like neurotypical
controls recollect contextual autobiographical information when
processing their own name.
When looking for the causes of the uneven memory
prole in ASD, the work of Hermelin and O’Connor7 and en-
suing supporting studies24,29 indicate that individuals with ASD
fail to encode word sequences in a meaningful way (deep en-
coding) as opposed to neurotypical controls who use semantic
and syntactical strategies to aid recall. In deep encoding, we
draw from semantic aspects of material to be remembered, for
example, considering category membership of words, which
typically leads to enhanced memory as opposed to shallower
levels of encoding that involve the processing of non-semantic
features, for example, counting the number of syllables.30 A lack
of encoding strategies will also lead to problems in remember-
ing more complex materials. Happé31 found that individuals with
ASD performed signicantly worse on memory tasks with more
complexity, both visual and auditory, when compared to neuro-
typical controls due to a lack of strategy and task organization.
The use of strategy in memory tasks was further ex-
amined using the relational and individual item paradigm32 that
tests free recall on items related to each other in category (rela-
tional processing) as opposed to items with semantic informa-
tion that specic only to the item itself (item specic process-
ing). Gaigg et al33 showed that participants with ASD recalled
overall fewer categories and less items in smaller but not larger
categories, and they were less likely than typical participants to
cluster items into their respective categories during recall. As
opposed to these selective differences in relational processing in
ASD, no signicant differences between groups were found in
the item-related processing portion of the study. As opposed to
the original Hunt and Seca32 paradigm, Gaigg et al33 presented
participants with a baseline and an orienting task which provid-
ed more practice and helped the ASD group overcome difcul-
ties in the orienting task by deploying their relational memory
processes effectively, which indicates that relational processing
strategies are available to individuals with ASD but their deploy-
ment needs to be aided. These ndings further substantiate the
Task Support Hypothesis34 which states that the memory difcul-
ties of individuals with ASD can be attenuated when the proce-
dure includes meaningful cues to the remembered material at
recall.
Solomon et al35 used the Relational and Item Specic
Encoding (RISE) task to compare 22 adolescents with ASD to
26 well-matched neurotypical control subjects. As opposed to
predictions, the ASD group did more poorly thank controls on
recognition for objects that had been encoded in the item-specif-
ic condition but showed no difference for objects that had been
encoded relationally. The study also found that the ASD group
relied relatively less on familiarity during item recognition fol-
lowing relational encoding than controls did. The ASD group
exhibited weaker cognitive control related to strategic memory
processes that produced less overall learning. Performance on
item and associative recognition improved with age in the ASD
group while performance in the control group was a product of
strategic learning processes. While these results may contradict
the general consensus of impaired relational memory processes
and intact item-specic memory in ASD, Solomon et al’s35 nd-
ings may be largely inuenced by the stimulus characteristics of
the RISE task where item-specic encoding relies on judgments
related to abstract features and relational encoding can be aided
PSYCHOLOGY AND COGNITIVE SCIENCES
Open Journal http://dx.doi.org/10.17140/PCSOJ-3-118
Psychol Cogn Sci Open J
ISSN 2380-727X
Page 3
with strong visuo-spatial ability. Abstraction is shown to be dif-
cult for individuals with ASD36 while visuo-spatial abilities are
considered strong.37
Neuroscientic evidence supports the theory of rela-
tional memory processes.38 The hippocampus has been identi-
ed as the site of domain-general relational memory processes
where individual features of an episode are integrated and or-
ganized.19,39,40 Morphological abnormalities of the hippocampus
are relatively well documented in ASD.41,42 Areas outside the
hippocampus, such as perirhinal, entorhinal and parahippocam-
pal areas are found to mediate more domain-specic item and
contextual processes.43,44
In summary, episodic remembering requires a person
to put memories into a spatio-temporal and self-referential con-
text, and relies on free recalls, which are areas of weakness in
ASD. Anatomical and functional differences in hippocampal
areas in ASD may be associated with these decits. Environ-
mental task support may help with the processing of relational
and more complex information related to spontaneous recall.
Item characteristics may play a role in some of the prior ndings
that contradicted general consensus ndings. Age may be an-
other factor in putting these ndings into perspective since ASD
studies have focused on younger age groups whereas episodic
memory is known to develop considerably through adolescence
and maturation does not occur until young adulthood.45 Further,
studies are needed to establish a more complete prole of memo-
ry processing in ASD including intellectually lower-functioning
individuals and adults with ASD.
REFERENCES
1. American Psychiatric Association, APD. Diagnostic and Sta-
tistical Manual of Mental Disorders. 5th ed. Arlington, VA, USA:
American Psychiatric Association; 2013.
2. Tulving E. Elements of Episodic Memory. Oxford: Oxford
University Press; 1983.
3. Tulving E. Memory and consciousness. Canadian Psycho-
logy. 1985; 26: 1-12.
4. Tulving E. Episodic Memory: From mind to brain. Annual Re-
view of Psychology. 2002; 53: 1-25. Web site. http://www.annual-
reviews.org/doi/pdf/10.1146/annurev.psych.53.100901.135114.
Accessed October 29, 2016.
5. Kanner L. Autistic disturbances of affective contact. Nervo-
us Child. 1943; 2: 217-250. Web site. https://simonsfoundation.
s3.amazonaws.com/share/071207-leo-kanner-autistic-affecti-
ve-contact.pdf. Accessed October 29, 2016.
6. Wing L. Asperger’s syndrome: A clinical account. Psycholo-
gical Medicine. 1981; 11: 115-129. doi: 10.1017/S003329170
0053332
7. Hermelin B, O’Connor N. Psychological Experiments With
Autistic Children. Oxford, UK: Pergamon Press; 1970.
8. Minshew N, Goldstein G. The pattern of intact and impaired
memory functions in autism. J Child Psychol Psychiatry. 2001;
42: 1095-1101. doi: 10.1111/1469-7610.00808
9. Bowler DM, Poirier M, Martin JS, Gaigg SB. Nonverbal short-
term serial order memory in autism spectrum disorder. J Abnorm
Psychol. 2016; 125(7): 886-893. doi: 10.1037/abn0000203
10. Poirier M, Martin JS, Gaigg SB, Bowler DM. Short-term
memory in autism spectrum disorder. J Abnorm Psychol. 2011;
120: 247-252. doi: 10.1037/a0022298
11. Neisser U. Two perceptually given aspects of the self and
their development. Developmental Review. 1991; 11: 197-209.
doi: 10.1016/0273-2297(91)90009-D
12. Povinelli DJ, Landau KR, Perilloux HK. Self-recognition
in children using delayed versus live feedback: Evidence of a
developmental asynchronicity. Child Development. 1996; 67:
1540-1554. doi: 10.1111/j.1467-8624.1996.tb01813.x
13. Lind SE, Bowler DM. Episodic memory and episodic future
thinking in adults with autism. J Abnorm Psychol. 2010; 119(4):
896-905. doi: 10.1037/a0020631
14. Zelazo PD, Burack JA, Benedetto E, Frye D. Theory of mind
and rule use in individuals with Down syndrome: A test of the
uniqueness and specicity claims. J Child Psychol Psychiatry.
1996; 37: 479-484. doi: 10.1111/j.1469-7610.1996.tb01429.x
15. Zelazo PD, Frye D. Cognitive complexity and control II:
The development of executive control in childhood. Curr Dir
Psychol Sci. 1998; 47: 121-126. Web site. https://www.jstor.org/
stable/20182520?seq=1#page_scan_tab_contents. Accessed Oc-
tober 29, 2016.
16. Zelazo PD, Burack JA, Boseovski J, Jacques S, Frye D.
A cognitive complexity and control framework for the study
of autism. In: Burack JA, Charman T, Yirmiya N, Zelazo PR,
eds. The Development of Autism: Perspectives from Theory and
Research. Mahwah, NJ, USA: Lawrence Erlbaum Associates;
2001: 195-217.
17. Brown MW, Aggleton JP. Recognition memory: What are
the roles of perirhinal cortex and hippocampus? Nat Rev Neuro-
sci. 2001; 2: 51-61. doi: 10.1038/35049064
18. Davachi L, Mitchell JP, Wagner AD. Multiple routes to
memory: Distinct medial temporal lobe processes build item
and source memories. Proceedings of the National Acade-
my of Science USA. 2003; 100(4): 2157-2162. doi: 10.1073/
pnas.0337195100
PSYCHOLOGY AND COGNITIVE SCIENCES
Open Journal http://dx.doi.org/10.17140/PCSOJ-3-118
Psychol Cogn Sci Open J
ISSN 2380-727X
Page 4
19. Holdstock JS, Mayes AR, Gong QY, Roberts N, Kapur N.
Item recognition is less impaired than recall and associative rec-
ognition in a patient with selective hippocampal damage. Hippo-
campus. 2004; 15: 203-215. doi: 10.1002/hipo.20046
20. Perner J. Experiential awareness and children’s episodic
memory. In: Schneider W, Weinert FE, eds. Interactions among
Aptitudes, Strategies and Knowledge in Cognitive Performance.
New York: Springer; 1990.
21. Baron-Cohen S, Leslie A, Frith U. Does the autistic child
have a ‘theory of mind’? Cognition. 1985; 21: 37-46. Web site.
http://autismtruths.org/pdf/3.%20Does%20the%20autistic%20
child%20have%20a%20theory%20of%20mind_SBC.pdf.
Accessed October 29, 2016.
22. Fletcher PC, Happé F, Frith U, et al. Other minds in the brain:
A functional imaging study of ‘theory of mind’ in story compre-
hension. Cognition. 1995; 57: 109-128. Web site. https://pdfs.
semanticscholar.org/8c9f/6785efcb75e18af9ca9a7fe479decff-
1b5a1.pdf. Accessed October 29, 2016.
23. Perner J, Ruffman T. Episodic memory and autonoetic con-
sciousness: Developmental evidence and a theory of childhood
amnesia. J Exp Child Psychol. 1995; 59: 516-548. Web site.
http://eric.ed.gov/?id=EJ507168. Accessed October 29, 2016.
24. Bowler DM, Gardiner JM, Grice S. Episodic memory and
remembering in adults with Asperger’s syndrome. J Autism Dev
Disord. 2000; 30: 295. doi: 10.1023/A:1005575216176
25. Bowler DM, Gardiner JM, Gaigg SB. Factors affecting con-
scious awareness in the recollective experience of adults with
Asperger’s syndrome. Conscious Cogn. 2007; 16: 124-143. doi:
10.1016/j.concog.2005.12.001
26. Lind SE, Bowler DM, Raber J. Spatial navigation, episodic
memory, episodic future thinking, and theory of mind in chil-
dren with autism spectrum disorder: Evidence for impairments
in mental simulation? Front Psychol. 2014; 5(1411): 1-20. doi:
10.3389/fpsyg.2014.01411
27. Abell F, Happe F, Frith U. Do triangles play tricks? Attribu-
tion of mental states to animated shapes in normal and abnormal
development. Cogn Dev. 2000; 15: 1-16. doi: 10.1016/S0885-
2014(00)00014-9
28. Winocour G. The hippocampus and thalamus: Their roles
in short- and long-term memory and the effects of interference.
Behavioral Brain Research. 1985; 16: 135-152.
29. Tager-Flusberg H. Semantic processing in the free recall
of autistic children. Br J Dev Psychol. 1991; 9: 417-430. doi:
10.1111/j.2044-835X.1991.tb00886.x
30. Craik FIM, Lockhart RS. Levels of processing: A framework
for memory research. J Verbal Learning Verbal Behav. 1972;
11(6): 671-684. doi: 10.1016/S0022-5371(72)80001-X
31. Happé F. The role of age and verbal ability in theory of mind
task performance of subjects with autism. Child Development.
1995; 66: 843-855.
32. Hunt RR, Seta CE. Category size effects in recall: The roles
of relational and individual item information. Journal of Experi-
mental Psychology: Learning, Memory and Cognition. 1984;
10: 454-464. Web site. http://psycnet.apa.org/index.cfm?fa=buy.
optionToBuy&id=1985-11356-001. Accessed October 29, 2016.
33. Gaigg SB, Gardiner JM, Bowler DM. Free recall in autism
spectrum disorder: The role of relational and item-specic en-
coding. Neuropsychologia. 2008; 46(4): 983-992. doi: 10.1016/j.
neuropsychologia.2007.11.011
34. Bowler DM, Matthews NJ, Gardiner JM. Asperger’s syn-
drome and memory: Similarity to autism but not amnesia.
Neuropsychologia. 1997; 35: 65-70.
35. Solomon M, McCauley JB, Iosif A, Carter CC, Ragland JD.
Cognitive control and episodic memory in adolescents with au-
tism spectrum disorder. Neuropsychologia. 2016; 89: 31-41. doi:
10.1016/j.neuropsychologia.2016.05.013
36. Solomon M, Frank MJ, Smith AC, Ly S, Carter CS. Tran-
sitive inference in adults with autism spectrum disorders. Cog
Affect Behav Neurosci. 2011; 11(3): 437-449. doi: 10.3758/
s13415-011-0040-3
37. Joseph RM, Steele SD, Meyer E, Tager-Flusberg H. Self-
ordered pointing in children with autism: Failure to use verbal
mediation in the service of working memory? Neuropsycholo-
gia. 2005; 43(10): 1400-1411. doi: 10.1016/j.neuropsycholo-
gia.2005.01.010
38. Nicolson R, DeVito, TJ, Vidal CN, Sui Y, Hayashi KM.
Detection and mapping of hippocampal abnormalities in au-
tism. Neuroimaging. 2006; 148(1): 11-21. doi: 10.1016/j.
pscychresns.2006.02.005
39. Eichenbaum H. Hippocampus: Cognitive processes and neu-
ral representations that underlie declarative memory. Neuron.
2004; 44: 109-120. doi: 10.1016/j.neuron.2004.08.028
40. Squire LR. Memory and the hippocampus: A synthesis from
ndings with rats, monkeys and humans. Psychological Review.
1992; 99: 195-231. doi: 10.1037/0033-295X.99.2.195
41. Groen W, Teluji M, Buitelaar J, Tendolka I. Amygdala and
hippocampus enlargement during adolescence in autism. J Am
Acad Child Adolesc Psychiatry. 2010; 49(6): 552-560. doi:
10.1016/j.jaac.2009.12.023
PSYCHOLOGY AND COGNITIVE SCIENCES
Open Journal http://dx.doi.org/10.17140/PCSOJ-3-118
Psychol Cogn Sci Open J
ISSN 2380-727X
Page 5
42. Nicolson R, DeVito TJ, Vidal CN, Sui Y, Hayashi KM. De-
tection and mapping of hippocampal abnormalities in autism.
Neuroimaging. 2006; 148: 11-21.
43. Davachi L. Item, context and relational episodic encoding in
humans. Curr Opin Neurobiol. 2006; 16: 693-700.
44. Mayes A, Montaldi D, Migo E. Associative memory and the
medial temporal lobes. Trends Cogn Sci. 2007; 11(3): 126-135.
doi: 10.1016/j.tics.2006.12.003
45. Ghetti S, Bunge SA. Neural changes underlying the
development of episodic memory during middle childhood. Dev
Cog Neurosci. 2012; 2(4): 381-395. doi: 10.1016/j.dcn.2012.
05.002
