Amnesia and future thinking: Exploring the role of memory in the quantity and quality of episodic future thoughts

Abstract

Objectives: To examine the impact of memory accessibility on episodic future thinking.

Design: Single-case study of neurological patient HCM and an age-matched comparison group of neurologically Healthy Controls.

Methods: We administered a full battery of tests assessing general intelligence, memory, and executive functioning. To assess autobiographical memory, the Autobiographical Memory Interview (Kopelman, Wilson, & Baddeley, 1990. The Autobiographical Memory Interview. Bury St. Edmunds, UK: Thames Valley Test Company) was administered. The Past Episodic and Future Episodic sections of Dalla Barba's Confabulation Battery (Dalla Barba, 1993, Cogn. Neuropsychol., 1, 1) and a specifically tailored Mental Time Travel Questionnaire were administered to assess future thinking in HCM and age-matched controls.

Results: HCM presented with a deficit in forming new memories (anterograde amnesia) and recalling events from before the onset of neurological impairment (retrograde amnesia). HCM's autobiographical memory impairments are characterized by a paucity of memories from Recent Life. In comparison with controls, two features of his future thoughts are apparent: Reduced episodic future thinking and outdated content of his episodic future thoughts.

Conclusions: This article suggests neuropsychologists should look beyond popular conceptualizations of the past-future relation in amnesia via focussing on reduced future thinking. Investigating both the quantity and quality of future thoughts produced by amnesic patients may lead to developments in understanding the complex nature of future thinking disorders resulting from memory impairments.

Practitioner points: We highlight the clinical importance of examining the content of future thoughts in amnesic patients, rather than only its quantitative reduction. We propose an explanation of how quantitative and qualitative aspects of future thinking could be affected by amnesia. This could provide a useful approach to understand clinical cases of impaired prospection.

Limitations: Systematic group investigations are required to fully examine our hypothesis. Although the current study utilized typical future thinking measures, these may be limited and we highlight the need to develop clinically relevant measures of prospection.

Keywords: amnesia; autobiographical memory; episodic memory; future thinking; imagination; mental time travel; prospection.