2009/01/23 by Rose McDermott, Dustin Tingley, Jonathan Cowden +2 · 5 citations
Social Sciences · Psychology · #Experimental Behavioral Economics Studies #Evolutionary Game Theory and Cooperation #Evolutionary Psychology and Human Behavior
paper · doi:10.1073/pnas.0808376106
openalex publication_date 2009/01/23 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/02
Monoamine oxidase A gene (MAOA) has earned the nickname "warrior gene" because it has been linked to aggression in observational and survey-based studies. However, no controlled experimental studies have tested whether the warrior gene actually drives behavioral manifestations of these tendencies. We report an experiment, synthesizing work in psychology and behavioral economics, which demonstrates that aggression occurs with greater intensity and frequency as provocation is experimentally manipulated upwards, especially among low activity MAOA (MAOA-L) subjects. In this study, subjects paid to punish those they believed had taken money from them by administering varying amounts of unpleasantly hot (spicy) sauce to their opponent. There is some evidence of a main effect for genotype and some evidence for a gene by environment interaction, such that MAOA is less associated with the occurrence of aggression in a low provocation condition, but significantly predicts such behavior in a high provocation situation. This new evidence for genetic influences on aggression and punishment behavior complicates characterizations of humans as "altruistic" punishers and supports theories of cooperation that propose mixed strategies in the population. It also suggests important implications for the role of individual variance in genetic factors contributing to everyday behaviors and decisions.