Anodal tDCS Over the Right Temporoparietal Junction Lowers Overbidding in Contests.

Minda Wang,Chengkang Zhu,Dahui Li,Jianbiao Li

doi:10.3389/fnins.2019.00528

Abstract

Overbidding, which means bidding over the Nash equilibrium, is commonly observed in competitive social interactions, such as a contest or auction. Recent neuroscience studies show that the right temporoparietal junction (rTPJ) is related to overbidding and associated with inferring the intentions of others during competitive interactions. The present study investigates the neural underpinnings of overbidding and how the rTPJ impacts bidding behavior by using tDCS to modulate the activation of the rTPJ. Participants completed a two-person proportional prize contest, in which overbidding was frequently observed and each participant's share of the prize was equal to the individual's expenditure divided by the aggregated expenditure. We observed a significant tDCS effect, i.e., participants' average expenditure and overbidding rate were significantly reduced in the anodal stimulation compared with the cathodal and sham stimulation. Possible explanations include that enhanced activity in the rTPJ via the anodal stimulation increased the accuracy of a participant's inference of the strategies of others, or a participant's concern for others, and thus helped the participant bid optimally. Our findings provide evidence supporting that the activation of the rTPJ in contests affects overbidding and bidding strategy, and further confirm that the rTPJ is involved in the inference of mental states in a competition context.

Highlights

When multiple agents participate in a completion for a single prize or part of a prize, their final expected payoffs are generally the expected prizes won from the competition minus the cost of their effort
A replicated observation in controlled lab experiments is that participants bid higher than the Nash equilibrium on average transcranial direct current stimulation (tDCS) Over right temporoparietal junction (rTPJ) Lowers Overbidding and that the total expenditure by all participants exceeds the value of the prize in some cases (Sheremeta, 2013; Dechenaux et al, 2015)
The goal of the current research is to clarify the casual involvement of the rTPJ in overbidding in contest by using tDCS technique to modulate the activity in rTPJ

Summary

Introduction

When multiple agents participate in a completion for a single prize or part of a prize, their final expected payoffs are generally the expected prizes won from the competition minus the cost of their effort. A replicated observation in controlled lab experiments is that participants bid higher than the Nash equilibrium on average tDCS Over rTPJ Lowers Overbidding and that the total expenditure by all participants exceeds the value of the prize in some cases (Sheremeta, 2013; Dechenaux et al, 2015). This phenomenon, i.e., participants tend to exert more effort which exceeds the Nash equilibrium in a competition is termed as overbidding (Sheremeta, 2013; Chowdhury et al, 2014; Dechenaux et al, 2015; Mago et al, 2016). Overbidding may cause significant social welfare waste (Tullock, 1980) and inhibit innovation and economic growth (Abbink and Serra, 2015)

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