Individual Differences in the Electrophysiology of Decision-Making in the Ultimatum Game and the Dictator Game

Abstract

This senior thesis used electroencephalography (EEG) to explore the neurophysiological correlates of decision-making in the Ultimatum Game (UG) in search of individual differences across the personality variable Social Value Orientation (SVO). Participants were selected from an undergraduate research requirement pool according to responses to a series of questionnaire items that characterized them as Cooperators, Individualists, or Competitors. The task consisted of a presentation of a series of fair and unfair offers supposedly decided by fellow classmates, followed by stochastic offers generated by a spinning wheel that participants later chose to either accept or reject. No main effects for SVO were observed for either MFN or the P300/LPP complex. A main effect was observed for both MFN and the P300/LPP complex such that advantageous wheel outcomes produced more MFN and a larger P300/LPP amplitude than both equal and disadvantageous wheel outcomes, which did not differ. A three-way global interaction in MFN was observed between participant sex, participant SVO and the proposer offer.