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Poster Session A: Tuesday, August 12, 1:30 – 4:30 pm, de Brug & E‑Hall

When jackpot misleads: The disrupting role of rare rewards in value learning

Luning He¹, Anina Rich, Yinan Cao², Konstantinos Tsetsos¹; ¹University of Bristol, ²Ecole Normale Supérieure – PSL

Presenter: Luning He

Prior research suggests that, when making decisions from experience, people tend to undervalue high-risk, high-reward options. This tendency has been attributed to underweighting the impact of rare rewards. However, this underweighting view may be confounded with risk avoidance. Here, we challenged a pure “underweighting” account using a two-armed bandit task. We found that choices for options with large but rare rewards were insensitive to their expected values. Instead, they were guided by a value-independent sampling bias for the rare-reward option. These findings suggest that the presence of large but rare rewards disrupts value-based decision-making, shifting the decision policy toward risk sensitivity rather than expected value maximization.

Topic Area: Reward, Value & Social Decision Making

Extended Abstract: Full Text PDF