title: Impulsive choice and altruistic punishment are correlated and increase in tandem with serotonin depletion.
abstract: Human cooperation may partly depend on the presence of individuals willing to incur personal costs to punish noncooperators. The psychological factors that motivate such 'altruistic punishment' are not fully understood; some have argued that altruistic punishment is a deliberate act of norm enforcement that requires self-control, while others claim that it is an impulsive act driven primarily by emotion. In the current study, we addressed this question by examining the relationship between impulsive choice and altruistic punishment in the ultimatum game. As the neurotransmitter serotonin has been implicated in both impulsive choice and altruistic punishment, we investigated the effects of manipulating serotonin on both measures. Across individuals, impulsive choice and altruistic punishment were correlated and increased following serotonin depletion. These findings imply that altruistic punishment reflects the absence rather than the presence of self control, and suggest that impulsive choice and altruistic punishment share common neural mechanisms.
authors.affiliation: Department of Experimental Psychology, University of Cambridge, Cambridge CB2 3EB, England. mc536@cam.ac.uk
authors.forename: Molly J
authors.initials: MJ
authors.lastname: Crockett
authors.forename: Luke
authors.initials: L
authors.lastname: Clark
authors.forename: Matthew D
authors.initials: MD
authors.lastname: Lieberman
authors.forename: Golnaz
authors.initials: G
authors.lastname: Tabibnia
authors.forename: Trevor W
authors.initials: TW
authors.lastname: Robbins
mesh_terms: D000328:Adult; D000533:Altruism; D000596:Amino Acids / Q000008:administration & dosage; D002755:Choice Behavior / Q000502:physiology*; D004311:Double-Blind Method; D005260:Female; D005717:Games, Experimental; D006801:Humans; D007175:Impulsive Behavior; D008297:Male; D011678:Punishment; D012701:Serotonin / Q000378:metabolism*; D014364:Tryptophan / Q000172:deficiency
chemical_list: D000596:Amino Acids; D012701:Serotonin; D014364:Tryptophan