Episodic Memory and Episodic Future Thinking Impairments in High-Functioning Autism Spectrum Disorder: An Underlying Difficulty With Scene Construction or Self-Projection?

Objective: There appears to be a common network of brain regions that underlie the ability to recall

past personal experiences (episodic memory) and the ability to imagine possible future personal

experiences (episodic future thinking). At the cognitive level, these abilities are thought to rely on

“scene construction” (the ability to bind together multimodal elements of a scene in mind—

dependent on hippocampal functioning) and temporal “self-projection” (the ability to mentally

project oneself through time—dependent on prefrontal cortex functioning). Although autism spectrum

disorder (ASD) is characterized by diminished episodic memory, it is unclear whether episodic

future thinking is correspondingly impaired. Moreover, the underlying basis of such impairments

(difficulties with scene construction, self-projection, or both) is yet to be established. The current

study therefore aimed to elucidate these issues. Method: Twenty-seven intellectually highfunctioning

adults with ASD and 29 age- and IQ-matched neurotypical comparison adults were

asked to describe (a) imagined atemporal, non-self-relevant fictitious scenes (assessing scene

construction), (b) imagined plausible self-relevant future episodes (assessing episodic future thinking),

and (c) recalled personally experienced past episodes (assessing episodic memory). Tests of

narrative ability and theory of mind were also completed. Results: Performances of participants with

ASD were significantly and equally diminished in each condition and, crucially, this diminution was

independent of general narrative ability. Conclusions: Given that participants with ASD were

impaired in the fictitious scene condition, which does not involve self-projection, we suggest the

underlying difficulty with episodic memory/future thinking is one of scene construction.