Electrophysiological Markers of Fairness and Selfishness Revealed by a Combination of Dictator and Ultimatum Games

Abstract

Individual behavior during financial decision making is motivated by fairness, but an unanswered question from previous studies is whether particular patterns of brain activity correspond to different profiles of fairness. Event Related Potentials (ERPs) were recorded from 39 participants who played the role of allocators in a Dictator Game (DG) and responders in an Ultimatum Game (UG). Two very homogeneous groups were formed by fair and selfish individuals. At fronto-central cortical sites, the latency of ERP early negativity (N1) was 10 ms shorter in selfish participants than in fair participants. In fair DG players, the subsequent positive wave P2 suggested that more cognitive resources were required when they allocated the least gains to the other party. P2 latency and amplitude in the selfish group supported the hypothesis that these participants tended to maximize their profit. During UG, we observed that medial frontal negativity (MFN) occurred earlier and with greater amplitude when selfish participants rejected less favorable endowment shares. In this case, all players received zero payoffs, which showed that MFN in selfish participants was associated with a spiteful punishment. At posterior-parietal sites, we found that the greater the selfishness, the greater the amplitude of the late positive component (LPC). Our results bring new evidence to the existence of specific somatic markers associated with the activation of distinct cerebral circuits by the evaluation of fair and unfair proposals in participants characterized by different expressions of perceived fairness, thus suggesting that a particular brain dynamics could be associated with moral decisions.

The effect of experiences of fairness on honest behavior: a behavioral and neural study

“…Previous studies proposed that certain brain dynamics could be linked to moral decisions ( Xu et al, 2020 ; Miraghaie et al, 2022 ). Among studies that adopted the DG paradigm, Miraghaie et al (2022) noted an unresolved question concerning whether specific patterns of brain activity correlate with different profiles of fairness. This question prompted the researchers to conduct an experiment that delved deeper into the topic.…”

“…This question prompted the researchers to conduct an experiment that delved deeper into the topic. In their study, Miraghaie et al (2022) used event-related potentials (ERPs) and randomly divided 39 participants into two groups (fair or selfish). All participants assumed the role of allocators in a DG.…”

“…Previous research has not determined how specific patterns of activity in the brain appeared when multiple profiles of fairness influenced individuals' moral decisions. Previous studies proposed that certain brain dynamics could be linked to moral decisions (Xu et al, 2020;Miraghaie et al, 2022). Among studies that adopted the DG paradigm, Miraghaie et al (2022) noted an unresolved question concerning whether specific patterns of brain activity correlate with different profiles of fairness.…”

Event‐related potentials during the ultimatum game in people with symptoms of depression and/or social anxiety

“…This has been related to negative cognitive biases and hypersensitivity to aversive events. However, others studies have observed a diminished MFN effect (difference between task conditions) in depression and anxiety, possibly linked to a negative bias in outcome expectation (Foti & Hajcak, 2009;Gu et al, 2010;Miraghaie et al, 2022). Finally, studies have also reported decreased MFN amplitudes in MD during positive stimuli, related to dysfunctional reward processing (Brush et al, 2018;Foti & Hajcak, 2009;Liu et al, 2014;Weiß, Rodrigues, et al, 2020).…”

“…We had no specific hypothesis regarding group differences on MFN during negative stimuli (i.e. mid‐value and unfair offers), since both an enhanced negative response (Judah et al, 2016; Mueller et al, 2015; Santesso et al, 2008; Tucker et al, 2003) as well as a blunted negative response due to bias negative expectation (Foti & Hajcak, 2009; Gu et al, 2010; Miraghaie et al, 2022) could be expected in MD and SA. Finally, we expected decreases in P3/LPP in the MD/SA group, as motivation deficits and negative cognitive biases (which could compete in resources with the P300; Barron et al, 2011; Smallwood et al, 2008) were likely to take place during a social task such as the UG.…”