Preemptive strike: An experimental study of fear-based aggression

The mere presence of a potential threat of attack was found to be sufficient to lead a significant proportion of participants to engage in preemptive attacks toward potential threats; this response occurred even without an incentive for either party to attack the other. We developed a new experimental game—the preemptive strike game (PSG)—to demonstrate this tendency for defensive aggression. We also found that the rate at which participants attacked an individual representing a potential threat was not influenced by their minimal group membership; participants were no less likely to preemptively attack a member of their own minimal group and no more likely to use aggression against members of another minimal group. These findings indicate a need to further examine the role that fear-based defensive aggression, rather than anger-based spiteful aggression, plays in inter-individual and inter-group conflict. •We found that 50% of the participants chose to use the preemptive attack option for no personal gain.•The option was rarely used when the opponent did not have a capability of preemptive attack.•Thus, the preemptive attack was fear-based, not involving the goal of hurting the opponent.•The frequency of the option use was not affected by the minimal group membership of the opponent.