title: Taking it easy when playing ultimatum game with a Down syndrome proposer: Effects on behavior and medial frontal negativity.
abstract: The ultimatum game (UG) is an endowment sharing game in which a proposer suggests a division of an asset to a recipient, who must accept or reject it. Economic studies showed that despite recipients usually rejecting unfair offers, perception and reaction to unfairness are highly dependent on who is the proposer. Event-related potentials (ERPs) commonly detected in UG games are the medial frontal negativity (MFN), a component detected in recipients facing unfair offers, and the P300, a component related to attentional and memory processes. Given this, we aimed to investigate the behavioral and ERP responses of healthy people playing the UG game with Down syndrome (DS) and typical development (TD) proposers. Nineteen subjects participated in this study. The UG behavioral data were similar to previous studies. ERP analysis showed no MFN in participants facing unfair offers. A higher P300 amplitude was detected when participants faced fair offers from TD compared to DS fair offers. We also found a positive correlation between P300 amplitude for TD offers and self-esteem scale score. Together these findings indicate that insertion of an atypical player in the UG led to changes in participants' perception and expectancy of the game.
authors.affiliation: a Social and Cognitive Neuroscience Laboratory and Developmental Disorders Program , Center for Health and Biological Sciences, Mackenzie Presbyterian University , São Paulo , Brazil.
authors.forename: Gabriel Gaudencio
authors.initials: GG
authors.lastname: Rêgo
authors.affiliation: a Social and Cognitive Neuroscience Laboratory and Developmental Disorders Program , Center for Health and Biological Sciences, Mackenzie Presbyterian University , São Paulo , Brazil.
authors.forename: Camila
authors.initials: C
authors.lastname: Campanhã
authors.affiliation: a Social and Cognitive Neuroscience Laboratory and Developmental Disorders Program , Center for Health and Biological Sciences, Mackenzie Presbyterian University , São Paulo , Brazil.
authors.forename: Julia Horta Tabosa
authors.initials: JHT
authors.lastname: do Egito
authors.affiliation: a Social and Cognitive Neuroscience Laboratory and Developmental Disorders Program , Center for Health and Biological Sciences, Mackenzie Presbyterian University , São Paulo , Brazil.
authors.forename: Paulo Sérgio
authors.initials: PS
authors.lastname: Boggio
mesh_terms: D000293:Adolescent; D000328:Adult; D000704:Analysis of Variance; D001921:Brain / Q000503:physiopathology*; D004314:Down Syndrome / Q000523:psychology; D004569:Electroencephalography; D005071:Evoked Potentials; D005260:Female; D005717:Games, Experimental; D006801:Humans; D007398:Interpersonal Relations; D008297:Male; D012919:Social Behavior; D055815:Young Adult
keywords: Down syndrome; MFN; P300; ultimatum game