Episodic future thinking: mechanisms and functions
Introduction
During the past decade, one of the most rapidly growing areas of research in cognitive neuroscience and psychology has focused on episodic future thinking: the capacity to imagine or simulate events that might occur in one's personal future (cf. [1, 2, 3]). This surge of research has been fueled in part by experimental demonstrations of striking cognitive and neural similarities when people are asked to imagine future experiences and remember past experiences (for detailed review, see [4]). Here we review recent studies of episodic future thinking in human adults that have yielded new insights into the mechanisms that support episodic future thinking and the functions that it serves (for recent research on episodic future thinking in children and non-human primates, see [5, 6, 7]).
Episodic future thinking is just one of several forms of future thinking or prospection [8]. A recently proposed taxonomy [9] distinguishes among four basic forms of future thinking: simulation (construction of a specific mental representation of the future), prediction (estimation of the likelihood of a future outcome), intention (setting of a goal), and planning (organization of steps for achieving a goal). Each form of future thinking is proposed to vary according to its representational contents on a gradient from episodic (specific autobiographical experiences that may happen in the future, such as a meeting with a friend that will take place next week) to semantic (more general or abstract states of the world that may occur in the future, such as the political landscape of the United States after an upcoming election). In the context of this taxonomy, episodic future thinking could potentially refer to episodic simulation, prediction, intention, or planning. In practice, however, studies of episodic future thinking almost always focus on episodic simulation; indeed, the terms episodic future thinking and episodic simulation are frequently used interchangeably (cf. [2, 3]), and we will follow that practice here.
Section snippets
Mechanisms of episodic future thinking
We first discuss recent research on cognitive mechanisms of episodic future thinking and then turn to research on neural mechanisms.
Functions of episodic future thinking
Evidence from thought sampling procedures indicates that episodic future thoughts occur frequently in everyday life and tend to be positively biased [66]. Early laboratory and clinical studies provided initial evidence that they serve a range of functions, including decision making, emotion regulation, intention formation, and planning [67], and recent work has both strengthened and broadened this evidence.
An impact of episodic future thinking on decision making has been clearly revealed in
Conclusions
During the past few years, the pace of research concerning episodic future thinking has accelerated, continuing a trend that began about a decade ago. There has been significant progress in characterizing the mechanisms that support episodic future thinking, and in identifying functions that episodic future thinking serves (see Figure 2).
Some key issues remain controversial, such as the nature of hippocampal contributions to episodic future thinking, and the related question of the extent to
Conflict of interest statement
Nothing declared.
References and recommended reading
Papers of particular interest, published within the period of review, have been highlighted as:
• of special interest
Acknowledgements
Preparation of this article was supported by National Institute of Mental Health Grant MH060941 and National Institute on Aging Grant AG08441 to DLS. RGB is supported by the Max Planck Society. We thank Alexis Carpenter, Aleea Devitt, Helen Jing, Kevin Madore, and Preston Thakral for helpful comments on earlier drafts of the manuscript.
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