Remembering the Past and Imagining the Future Amongst Individuals with Autism

Background: Recent research has indicated that the same neurocognitive system that underlies the capacity to remember past experiences (episodic memory) also underlies the capacity to imagine future experiences (prospection) (Buckner & Carroll, 2007; Hassabis & Maguire, 2007; Spreng et al., in press).  Indeed, this discovery was considered to be one of the major scientific breakthroughs of 2007 (The News Staff, 2007, Science, 318, 1844-1849).  It is established that individuals with autism have diminished episodic memory (see Boucher & Bowler, 2008).  However, very little research has sought to assess prospection amongst individuals with autism.  Prospection is essential for flexibility of thought and action because it enables one to simulate and predict future scenarios, thereby allowing one to plan and select the optimal course of action.  Thus, impairments in this domain may help to explain why individuals with autism exhibit restricted, repetitive and stereotyped patterns of behaviour.  Difficulty in acting with the future in mind may result in over-dependence on routinised, inflexible patterns of behaviour.    

Objectives: The main aims of this study were to establish: (a) whether prospection as well as episodic memory is impaired amongst individuals with autism; (b) whether prospection and episodic memory are related amongst people with autism; (c) whether imagined and/or remembered events differ qualitatively between individuals with and without autism; (d) the extent to which predicted impairments in prospection contribute to behavioural inflexibility amongst individuals with autism. 

Methods: Participants were high-functioning adults with autism and typical adults who were matched on age, sex, verbal IQ and performance IQ.  Autism diagnoses were confirmed using the Autism Diagnostic Observation Schedule (Lord et al., 1999) and all participants completed the Autism Quotient (Baron-Cohen et al., 2001).  The experimental task was based on one used previously by D’Argembeau and Van der Linden (2004) with typically developing adults.  Participants were prompted to recall seven specific events from the past and to imagine seven specific likely-to-occur events in the future.  In order to assess the subjective qualities of these memories/images, participants were asked to complete an adapted version of the Memory Characteristics Questionnaire (MCQ) (Johnson et al, 1988) for each event.  Participants were also tested for word, category, and ideational fluency. 

Results: Preliminary results, based on 22 participants (more data are currently being collected), indicate that: (a) individuals with autism showed higher response latencies, and were less likely to recall/imagine specific past/future events (even after controlling for fluency); (b) within each group, the capacity to recall the past was correlated with the capacity to imagine the future; (c) remembered/imagined events differed qualitatively between participants with and without autism on a number of dimensions (as determined by subjective ratings on the MCQ); and (d) among individuals with autism, impairments in prospection were related to impairments in behavioural flexibility.  

Conclusions: These results have implications for our understanding of the inflexible behaviour that characterises autism, suggesting that difficulties with imagining future events may impact upon the capacity of individuals with autism to plan and act for the future.