Reward at encoding but not retrieval modulates memory for detailed events

Area of Science:

• Cognitive psychology
• Neuroscience of reward and memory

Background:

• Previous research focused on rewards improving memory for simple stimuli.
• Limited understanding of how rewards affect memory for complex, naturalistic events.

Purpose of the Study:

• To investigate the impact of explicit rewards on memory for complex events.
• To determine if rewards at encoding versus retrieval differentially affect memory performance.
• To explore the underlying mechanisms of reward effects on memory using computational modeling.

Main Methods:

• Participants encoded videos of naturalistic events paired with varying monetary incentives.
• A recognition test assessed memory for event, perceptual, and contextual details.
• Reward manipulation was applied at either encoding or retrieval.
• Drift Diffusion Modelling analyzed changes in encoding fidelity and response caution.

Main Results:

• Explicit rewards significantly improved memory performance only when presented during encoding.
• The beneficial effect of encoding rewards was consistent across different detail types.
• Drift Diffusion Modelling indicated enhanced encoding fidelity (increased drift rate) without altered response caution (stable response threshold).

Conclusions:

• Explicit rewards facilitate memory for complex events primarily by enhancing the encoding process.
• Attentional mechanisms are likely involved in how rewards improve memory encoding.
• Reward timing is critical; presentation at encoding is more effective than at retrieval for complex event memory.