Adaptive scaling of reward in episodic memory: a replication study.

Alice Mason,Simon Farrell,Casimir Ludwig

doi:10.1080/17470218.2016.1233439

Abstract

Reward is thought to enhance episodic memory formation via dopaminergic consolidation. Bunzeck, Dayan, Dolan, and Duzel [(2010). A common mechanism for adaptive scaling of reward and novelty. Human Brain Mapping, 31, 1380-1394] provided functional magnetic resonance imaging (fMRI) and behavioural evidence that reward and episodic memory systems are sensitive to the contextual value of a reward-whether it is relatively higher or lower-as opposed to absolute value or prediction error. We carried out a direct replication of their behavioural study and did not replicate their finding that memory performance associated with reward follows this pattern of adaptive scaling. An effect of reward outcome was in the opposite direction to that in the original study, with lower reward outcomes leading to better memory than higher outcomes. There was a marginal effect of reward context, suggesting that expected value affected memory performance. We discuss the robustness of the reward memory relationship to variations in reward context, and whether other reward-related factors have a more reliable influence on episodic memory.

Highlights

Reward is thought to enhance episodic memory formation via dopaminergic consolidation. Bunzeck, Dayan, Dolan, and Duzel [(2010)
Dopaminergic neurons in the midbrain appear to respond to prediction error, so that if a smaller than expected reward is given, the neurons respond below their baseline firing rate, and if a larger than expected reward is given, the neurons respond above their baseline (Schultz, 1998)
By adding the RCorr and FCorr estimates together an overall corrected hit rate for recognition memory was obtained in the same manner as in Bunzeck et al During encoding, participants responded quickly and accurately to the reward task

Summary

Introduction

Reward is thought to enhance episodic memory formation via dopaminergic consolidation. Bunzeck, Dayan, Dolan, and Duzel [(2010). It did not appear to offer additional information over the main effect in the ANOVA, in order to fully replicate the original analysis we conducted a post hoc t test comparing the lower and the higher reward outcomes (collapsing across context).

Results

Conclusion