Expected Value of Reward Predicts Episodic Memory for Incidentally Learnt Reward-Item Associations

Abstract

In this paper, we draw connections between reward processing and cognition by behaviourally testing the implications of neurobiological theories of reward processing on memory. Single-cell neurophysiology in non-human primates and imaging work in humans suggests that the dopaminergic reward system responds to different components of reward: expected value; outcome or prediction error; and uncertainty of reward (Schultz et al., 2008). The literature on both incidental and motivated learning has focused on understanding how expected value and outcome-linked to increased activity in the reward system-lead to consolidation-related memory enhancements. In the current study, we additionally investigate the impact of reward uncertainty on human memory. The contribution of reward uncertainty-the spread of the reward probability distribution irrespective of the magnitude-has not been previously examined. To examine the effects of uncertainty on memory, a word-learning task was introduced, along with a surprise delayed recognition memory test. Using Bayesian model selection, we found evidence only for expected value as a predictor of memory performance. Our findings suggest that reward uncertainty does not enhance memory for individual items. This supports emerging evidence that an effect of uncertainty on memory is only observed in high compared to low risk environments.

Two routes to value-based decisions in Parkinson’s disease: differentiating incremental reinforcement learning from episodic memory

“…However, the extent to which learning and decisions are based instead on single past encounters has been a primary focus of much recent work. [9][10][11]23,24,26 While computational theory has suggested that individual events may be particularly useful when experience with a task is limited, 29,57 experimental studies have demonstrated that they are relied upon even throughout tasks that can be solved normatively with incremental learning alone. [9][10][11] This suggests that information encoded in a single shot with episodic memory is commonly recruited for reward-based learning and decision-making.…”

“…1,19,20 In contrast, episodic memory supports the encoding and retrieval of single experiences and largely depends upon independent neural circuitry, including the hippocampus. [9][10][11][21][22][23][24][25][26][27] Understanding how these systems each contribute to performance on reward-based learning and decision tasks has been challenging, in part because typical experiments only measure one type of behavior. In particular, most tasks require participants to choose between a set of repeated and often highly familiar options.…”

The Effects of Social Rewards on Incidental Episodic Memory

“…In turn, stimuli that have been previously associated with rewards automatically capture attention (Della Libera and Chelazzi, 2009;Hickey et al 2011;Anderson et al, 2014) and are better remembered (Wittmann et al, 2005;Adcock et al, 2006;Callan and Schweighofer, 2008). This is also applicable to episodic memory consolidation for both explicitly (Wittmann et al, 2011) and incidentally encoded stimulus features (Mason et al, 2019). Prioritizing memory for events that occurred close to the receipt of a reward helps to replicate those instances in the future.…”