Separate Memory-Enhancing Effects of Reward and Strategic Encoding

Abstract

Memory encoding for important information can be enhanced both by reward anticipation and by intentional strategies. These effects are hypothesized to depend on distinct neural mechanisms, yet prior work has provided only limited evidence for their separability. We aimed to determine whether reward-driven and strategic mechanisms for prioritizing important information are separable, even if they may also interact. We examined the joint operation of both mechanisms using fMRI measures of brain activity. Participants learned abstract visual images in a value-directed recognition paradigm. On each trial, two novel images were presented simultaneously in different screen quadrants, one arbitrarily designated as high point value and one as low value. Immediately after each block of 16 study trials, the corresponding point rewards could be obtained in a test of item recognition and spatial location memory. During encoding trials leading to successful subsequent memory, especially of high-value images, increased activity was observed in dorsal frontoparietal and lateral occipitotemporal cortex. Furthermore, activity in a network associated with reward was higher during encoding when any image, of high or low value, was subsequently remembered. Functional connectivity between right medial temporal lobe and right ventral tegmental area, measured via psychophysiological interaction, was also greater during successful encoding regardless of value. Strategic control of memory, as indexed by successful prioritization of the high-value image, affected activity in dorsal posterior parietal cortex as well as connectivity between this area and right lateral temporal cortex. These results demonstrate that memory can be strengthened by separate neurocognitive mechanisms for strategic control versus reward-based enhancement of processing.

Influence of Reward Motivation on Directed Forgetting in Younger and Older Adults

“…The purpose of presenting the reward cue during stimulus presentation was to test the effect of reward anticipation on the ability to control memory by either intentionally remembering or forgetting the word. Reward anticipation has been shown to engage the reward network but also other brain regions that could either increase inhibitory cognitive control of memory that would benefit both goal-directed remembering and forgetting (e.g., Cohen et al, 2016 ; Ferdinand and Czernochowski, 2018 ) or more automatic episodic memory formation (e.g., Spaniol et al, 2014 ; Cohen et al, 2019 ; Bowen et al, 2020 ) that would benefit remembering only, making forgetting more difficult. This is the first study to examine the role of monetary reward anticipation and its interaction with memory cues in a directed forgetting paradigm, adding to a small literature examining the effect of motivation on directed forgetting, more broadly.…”

“…Since cognitive control is thought to underlie older adults’ reduced ability to intentionally forget, rewards could potentially increase goal-directed remembering and forgetting. A second interpretation for the motivated memory findings above is that reward motivation enhances processing of high-value compared to low-value stimuli, but this processing is relatively automatic, rather than controlled (e.g., Cohen et al, 2019 ; Bowen et al, 2020 ). Neuroimaging provides evidence for this interpretation as reward anticipation boosts activation in the ventral tegmental area and triggers dopaminergic modulation of hippocampal consolidation processes.…”

Developmental change in prefrontal cortex recruitment supports the emergence of value-guided memory

“…But not all experiences are equally useful to remember — the information we encounter varies in its utility in helping us gain future reward. By adulthood, individuals demonstrate the ability to prioritize memory for information that is likely to be most rewarding in the future (Adcock et al, 2006; M. S. Cohen et al, 2014, 2019; Hennessee et al, 2019; Shigemune et al, 2014; Shohamy & Adcock, 2010; Wittmann et al, 2005). Children, however, demonstrate weaker memory selectivity, often remembering relatively inconsequential information at the expense of higher-value items or associations (Castel et al, 2011; Hanten et al, 2007; Nussenbaum et al, 2020).…”

Intact strategic retrieval processes in older adults: no evidence for age-related deficits in source-constrained retrieval

“…Furthermore, recent research has only begun to assess the relationship between reward-induced motivation and strategic control processes in terms of their effects on memory (e.g. Cohen, Cheng, Paller & Reber, 2019), and how that relationship may differ across age groups, memory stages (e.g. encoding vs. retrieval), and memory processes (i.e.…”

“…Furthermore, although some influences of reward on encoding are thought to depend on relatively automatic dopaminergic brain systems (e.g. Wittmann et al, 2005), reward effects on memory can also be mediated through strategic recruitment of cognitive control processes (Cohen, et al, 2019). For example, external rewards increase the use of strategic memory processes in younger samples who will prioritise encoding of rewarded information at the expense of non-rewarded information (Cohen, Rissman, Suthana, Castel, & Knowlton, 2014), with some evidence suggesting older adults will also strategically prioritise encoding in this way (Castel, Farb, & Craik, 2007;Castel et al, 2013;Cohen, Rissman, Suthana, Castel & Knowlton, 2016).…”