Testosterone and Aggression in a Simulated Crisis Game

Higher levels of testosterone are associated with more aggression, particularly among older women and younger men.


In behavioral economics, the question of whether genetics or environments determine behavior has occupied researchers over the years. How nature and nurture influence aggressive behavior has been of particular interest. This study examines how biology and environment interact in generating aggression in the context of a simulated war game. Understanding the drivers of aggression is important for designing appropriate interventions. Existing research suggests testosterone is both a direct and indirect cause of aggression, leading the authors of this study to take a closer look at the effect of testosterone on aggression in a simulated crisis game.


Both male and female participants in this study with high levels of testosterone also displayed higher levels of aggression.

  • High-testosterone people were much more likely to engage in aggressive behavior than low-testosterone people. Older women with relatively more testosterone, as well as younger men who naturally have more testosterone, expressed more aggression (through unprovoked attacks in the laboratory game) than younger women and older men.

In short, levels of testosterone and aggression are positively correlated with one another.


The study involved 186 subjects from Harvard Business School’s experimental subject pool, aged 18 to 65, who participated in a simulation crisis game. In the game, subjects were randomly paired in same-sex or mixed-sex dyads. They were given instructions to role-play the leader of a country in conflict with a neighbor over newly discovered diamond mines on disputed territory. The simulation ran for six rounds, and in each round subjects undertook different tasks. The game was structured so that players could win either through negotiations or war.

Testosterone levels were measured before, mid-way and after the simulation. Demographic data and mood inventories were collected through a survey both before and after the game.

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