Psychology and Cognitive Sciences

Open journal

ISSN 2380-727X

Memory in Autism: A Case of Remembering Versus Knowing

Sabine Huemer*

Received: October 30th, 2016; Accepted: December 5th, 2016; Published: December 6th, 2016

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 deficits and repetitive patterns of behavior including intense preoccupations and inflexible adherence to routines. ASD may occur with or without accompanying intellectual impairment and the severity of the disorder may fluctuate 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 indicated a generally higher (Asperger’s) or lower level of functioning (autism). This brief report attempts 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 recognition, 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 specific 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 factual 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 findings using verbal material,10 these results indicate that order processing appears to be a cross-domain deficit in ASD.

Free recall and the ability of mental time travel2 have been related to the comprehension 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 problems 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 deficits in 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 episodic memory deficits, 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. However, 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 attention 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 spatiotemporal 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 neurotypical 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 Interestingly, spatial navigation as tested on the computer-simulated “memory island” task was significantly 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 first names, (Huemer S et al unpublished data, 2016) found that individuals with ASD with high verbal ability, just like neurotypical controls, activated right hippocampal processes when hearing their own first name, while individuals with ASD with low verbal ability scores activated left thalamic processes associated with the memorization of new events.28 Since perirhinal areas receive afferents from the nucleus reuniens of the thalamus, these findings 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 find 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 profile in ASD, the work of Hermelin and O’Connor7 and ensuing 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 remembering more complex materials. Happé31 found that individuals with ASD performed significantly worse on memory tasks with more complexity, both visual and auditory, when compared to neurotypical controls due to a lack of strategy and task organization.

The use of strategy in memory tasks was further examined using the relational and individual item paradigm32 that tests free recall on items related to each other in category (relational processing) as opposed to items with semantic information that specific only to the item itself (item specific processing). 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 significant 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 provided more practice and helped the ASD group overcome difficulties 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 deployment needs to be aided. These findings further substantiate the Task Support Hypothesis34 which states that the memory difficulties of individuals with ASD can be attenuated when the procedure includes meaningful cues to the remembered material at recall.

Solomon et al35 used the Relational and Item Specific 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-specific 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 following 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-specific memory in ASD, Solomon et al’s35 findings may be largely influenced by the stimulus characteristics of the RISE task where item-specific encoding relies on judgments related to abstract features and relational encoding can be aided with strong visuo-spatial ability. Abstraction is shown to be difficult for individuals with ASD36 while visuo-spatial abilities are considered strong.37

Neuroscientific evidence supports the theory of relational memory processes.38 The hippocampus has been identified as the site of domain-general relational memory processes where individual features of an episode are integrated and organized.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 parahippocampal areas are found to mediate more domain-specific item and contextual processes.43,44

In summary, episodic remembering requires a person to put memories into a spatio-temporal and self-referential context, 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 deficits. Environmental 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 findings that contradicted general consensus findings. Age may be another factor in putting these findings 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 profile of memory processing in ASD including intellectually lower-functioning individuals and adults with ASD.

1. American Psychiatric Association, APD. Diagnostic and Statistical 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 Psychology. 1985; 26: 1-12.

4. Tulving E. Episodic Memory: From mind to brain. Annual Review of Psychology. 2002; 53: 1-25. Website. http://www.annualreviews.org/doi/pdf/10.1146/annurev.psych.53.100901.135114. Accessed October 29, 2016.

5. Kanner L. Autistic disturbances of affective contact. Nervous Child. 1943; 2: 217-250. Website. https://simonsfoundation. s3.amazonaws.com/share/071207-leo-kanner-autistic-affective-contact.pdf. Accessed October 29, 2016.

6. Wing L. Asperger’s syndrome: A clinical account. Psychological 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 shortterm 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 specificity 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. Website. https://www.jstor.org/ stable/20182520?seq=1#page_scan_tab_contents. Accessed October 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 Neurosci. 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 Academy of Science USA. 2003; 100(4): 2157-2162. doi: 10.1073/ pnas.0337195100

19. Holdstock JS, Mayes AR, Gong QY, Roberts N, Kapur N. Item recognition is less impaired than recall and associative recognition in a patient with selective hippocampal damage. Hippocampus. 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. Website. 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 comprehension. Cognition. 1995; 57: 109-128. Website. https://pdfs. semanticscholar.org/8c9f/6785efcb75e18af9ca9a7fe479decff1b5a1.pdf. Accessed October 29, 2016.

23. Perner J, Ruffman T. Episodic memory and autonoetic consciousness: Developmental evidence and a theory of childhood amnesia. J Exp Child Psychol. 1995; 59: 516-548. Website. 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 conscious 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 children 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? Attribution 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. doi: 10.1016/0166-4328(85)90088-9

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.2044835X.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 Experimental Psychology: Learning, Memory and Cognition. 1984; 10: 454-464. Website. 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-specific encoding. Neuropsychologia. 2008; 46(4): 983-992. doi: 10.1016/j. neuropsychologia.2007.11.011

34. Bowler DM, Matthews NJ, Gardiner JM. Asperger’s syndrome and memory: Similarity to autism but not amnesia. Neuropsychologia. 1997; 35: 65-70. doi: 10.1016/s0028-3932(96)00054-1

35. Solomon M, McCauley JB, Iosif A, Carter CC, Ragland JD. Cognitive control and episodic memory in adolescents with autism 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. Transitive 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. Selfordered pointing in children with autism: Failure to use verbal mediation in the service of working memory? Neuropsychologia. 2005; 43(10): 1400-1411. doi: 10.1016/j.neuropsychologia.2005.01.010

38. Nicolson R, DeVito, TJ, Vidal CN, Sui Y, Hayashi KM. Detection and mapping of hippocampal abnormalities in autism. Neuroimaging. 2006; 148(1): 11-21. doi: 10.1016/j. pscychresns.2006.02.005

39. Eichenbaum H. Hippocampus: Cognitive processes and neural 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 findings 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

42. Nicolson R, DeVito TJ, Vidal CN, Sui Y, Hayashi KM. Detection and mapping of hippocampal abnormalities in autism. Neuroimaging. 2006; 148: 11-21.doi: 10.1016/j.pscychresns.2006.02.005

43. Davachi L. Item, context and relational episodic encoding in humans. Curr Opin Neurobiol. 2006; 16: 693-700. doi: 10.1016/j.conb.2006.10.012

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

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