A Neural Marker of Costly Punishment Behavior
“The ultimatum game nicely illustrates that individuals indeed use costly punishment to enforce social norms.”
Abstract (Via Sagepub)
Human readiness to incur personal costs to punish norm violators is a key force in the maintenance of social norms. The willingness to punish is, however, characterized by vast individual heterogeneity that is poorly understood. In fact, this heterogeneity has so far defied explanations in terms of individual-level demographic or psychological variables. Here, we use resting electroencephalography, a stable measure of individual differences in cortical activity, to show that a highly specific neural marker—baseline cortical activity in the right prefrontal cortex—predicts individuals’ punishment behavior. The analysis of task-independent individual variation in cortical baseline activity provides a new window into the neurobiology of decision making by bringing dispositional neural markers to the forefront of the analysis
Introduction (Via Sagepub)
Civilized human life depends on the maintenance of elementary social norms, many of which are enforced by individuals’ willingness to sanction violations even at personal cost. A large amount of cultural and individual variation characterizes costly punishment behavior, however (Camerer, 2003; Henrich et al., 2005; Herrmann, Thoni, & Gachter, 2008). Recent attempts to explain cultural variation in terms of key economic and group variables have been relatively successful (Henrich et al., 2005; Herrmann et al., 2008), but the sources of individualvariation are still very poorly understood. Typically, individual variables such as gender, income, wealth, or education have low predictive power, and their influence varies strongly, depending on the details of the study (Camerer, 2003). Recent evidence has suggested a genetic component of up to 40% of individual variation in costly punishment behavior.
In a study by Wallace, Cesarini, Lichtenstein, and Johannesson (2007), in which both monozygotic and dizygotic twins played the ultimatum game, the behavioral correlation between monozygotic twins was much larger than in dizygotic twins. This study is consistent with the idea that dispositional variation might explain individual variation in costly punishment, but so far there is no evidence indicating that stable psychological personality traits or stable neural characteristics affect punishment behavior. Therefore, we examined whether dispositional differences in neural baseline activity explained individual variation in punitive behavior. Answering this question required a measure that was both stable over time and allowed the examination of individuals’ neurophysiological characteristics at rest. We used resting electroencephalography (EEG) to measure tonic cortical activity, which is stable over time and can therefore capture dispositional individual differences (e.g., Kondacs & Szabo, 1999; Näpflin, Wildi, & Sarnthein, 2007; Tomarken, Davidson, Wheeler, & Kinney, 1992).