Differential effects of real versus hypothetical monetary reward magnitude on risk-taking behavior and brain activity

Sihua Xu,Hengyi Rao,Fenghua Wang,Zijing Yang,Zhe Qu,Fan Yang,Zhuo Fang,Yu Pan

doi:10.1038/s41598-018-21820-0

Abstract

Human decisions are more easily affected by a larger amount of money than a smaller one. Although numerous studies have used hypothetical money as incentives to motivate human behavior, the validity of hypothetical versus real monetary rewards remains controversial. In the present study, we used event-related potential (ERP) with the balloon analogue risk task to investigate how magnitudes of real and hypothetical monetary rewards modulate risk-taking behavior and feedback-related negativity (FRN). Behavioral data showed that participants were more risk averse after negative feedback with increased magnitude of real monetary rewards, while no behavior differences were observed between large and small hypothetical monetary rewards. Similarly, ERP data showed a larger FRN in response to negative feedback during risk taking with large compared to small real monetary rewards, while no FRN differences were observed between large and small hypothetical monetary rewards. Moreover, FRN amplitude differences correlated with risk-taking behavior changes from small to large real monetary rewards, while such correlation was not observed for hypothetical monetary rewards. These findings suggest that the magnitudes of real and hypothetical monetary rewards have differential effects on risk-taking behavior and brain activity. Real and hypothetical money incentives may have different validity for modulating human decisions.

Highlights

Human decisions are motivated by various kinds of rewards, including money as a secondary but strong incentive for regulating human behavior
Further post-hoc comparisons indicated that the feedback-related negativity (FRN) in response to negative feedback with large real monetary reward was significantly more negative-ongoing than that with small real monetary reward (3.52 ± 1.29 μV vs. 5.65 ± 1.54 μV, t(19) = −3.69, p = 0.002, ω2 = 0.146), while no differences were found for the FRN in response to negative feedback with large hypothetical monetary reward compared to that with small hypothetical monetary reward (5.76 ± 1.53 μV vs. 4.81 ± 1.75 μV, t(19) = 1.52, p = 0.14)
The present study examined how the magnitudes of real and hypothetical monetary reward modulate risk-taking behavior and brain activity using event-related potential with a well-validated Balloon Analogue Risk Task (BART) paradigm

Summary

Introduction

Human decisions are motivated by various kinds of rewards, including money as a secondary but strong incentive for regulating human behavior. Using a Balloon Analogue Risk Task (BART) paradigm, our previous study found that individuals became more risk averse after negative feedback (i.e., money loss) with real compared to hypothetical monetary rewards[19]. A recent event-related potential (ERP) study demonstrated larger feedback-related negativity (FRN) in response to money loss during the BART risky decision making with real rewards compared to hypothetical rewards, which may reflect greater prediction error or regret emotion after real monetary losses[17]. A few studies suggested that individuals may display different risk-taking and decision-making behavior changes to the increased magnitude of hypothetical versus real monetary rewards[19,25]. Previous studies have shown that the FRN is sensitive to outcome valence and magnitude and may reflect the evaluation of motivational and emotional consequences of decision outcomes[35,36,37]

Methods

Results

Conclusion