Value-based decisions involve sequential sampling from memory

Abstract

Deciding between two equally appealing options can take considerable time. This observation has puzzled economists and philosophers, because more deliberation only delays the reward.Here we show that this seemingly irrational behavior is explained by the constructive use of memory. Using functional brain imaging in humans, we show that how long it takes to decide between two familiar food items is related to activity in the hippocampus, within specific regions shown to be associated with the retrieval of long-term memories. Moreover, we show that value is partially constructed during deliberation to resolve preference, and this constructive process changes behavior and brain responses. These results render memory as a supplier of evidence in value-based decisions, resolving a central paradox of choice.

Episodic memory retrieval success is associated with rapid replay of episode content

“…10,42). The ability to reactivate episodes in a highly compressed manner provides a novel mechanism for very rapid retrieval and replay of previous experiences during choice (44)(45)(46), and our results reported here can motivate new directions of research into memory encoding, consolidation and decision making. Further, the flexible direction of episodic retrieval replay events that we identify may affect choice dynamics.…”

To What Extent Memory Could Contribute to Impaired Food Valuation and Choices in Obesity?

“…Analogous to the drift diffusion model widely used in studies on perceptual decision-making (Gold and Shadlen, 2007), once this sequentially updated value reaches a certain threshold, a decision will be committed. One recent fMRI study provided initial empirical support to this model by showing that hippocampal activation was related to the time it took the participants to make a choice between two familiar food items, presumably reflecting the amount of information sampled from memory (Bakkour et al, 2018). Similarly, hippocampal lesion patients also showed deficits making binary choices between familiar food items, but had performance comparable to healthy controls on a number-comparison control task, again highlighting the role of hippocampus in value construction from memory (Enkavi et al, 2017).…”

Hippocampal-entorhinal transformations in abstract frames of reference

“…Hippocampal fMRI signal increases were primarily associated with deliberation and subjective confidence, suggesting that hippocampal responses observed in our task may reflect increased sampling of personal experience during memory-guided decision-making (Shadlen & Shohamy, 2016;Bornstein & Norman, 2017;Bakkour et al, 2018). Notably, the hippocampal responses observed here closely resemble putative pattern separation signals in episodic memory (Marr, 1971).…”

“…In contrast, entorhinal/subicular grid and boundary vector representations use multiple reference frames, and can either be continuously or discretely coded (Hartley et al, 2013;Diehl et al, 2017). Our data potentially extend this functional dissociation to memory-guided decision-making, where the body of the hippocampus generally related to greater sampling of personal experience (Bornstein & Norman, 2017;Bakkour et al, 2018;Shadlen & Shohamy, 2016), while the entorhinal/subicular region related to discriminating the relative distance between the stranger's rating and choice options differently, depending on the familiar individuals being compared (i.e., reference frame). Further support for this distinction stems from the putative role of the entorhinal cortex (Buzsaki & Moser, 2013;Maas et al, 2015;Navarro et al, 2015) and subicular region (Dalton & Maguire, 2017) in integrating incoming sensory input with learned hippocampal representations.…”