The Treaty of Versailles took force exactly one hundred years ago today on January 10, 1920. The Allied and Associated Powers, the victors of WWI, imposed the Treaty on the Central Powers and codified the terms of peace between the Allies and Germany There was never to be another Great War, but less than twenty years later the world was torn asunder again. What happened?

It is widely agreed that the Treaty of Versailles failed because it was filled with harsh punishment and unrealistic expectations of massive reparations payments and demilitarization imposed on Germany for its wrongdoing. Fundamentally, the Versailles Treaty was not a peace treaty but rather a quintessential example of revenge. It is easy to understand the desire for revenge given the devastation wrought by the war. But history also makes it eminently clear that revenge exacts a heavy toll – on us as nations and as individuals. So why do we do it? What is the psychology of revenge? And what are some lessons for today?
1. The psychology of revenge. At its core, revenge is about inflicting hurt or harm on someone to achieve retribution for perceived personal injury or wrong suffered. As much as we hate to admit it, revenge is one of those intense feelings that comes up for every single human being. We have all had the experience of relishing the fantasy of turning the tables on someone who has badly hurt us. Neuroscience research shows that revenge can be mapped in the brain. In studies of revenge, when individuals are wronged and then invited to imagine their revenge, the caudate nucleus, known to process rewards in the brain, is activated. Yes, the human brain can take pleasure in just imagining revenge. But the positive effects are fleeting and bittersweet at best.
2. Evolutionary Underpinnings of Revenge. University of Miami psychology professor Michael McCullough explains that the impulse for revenge evolved to harm someone in the future after that individual has already imposed harm on us in the first place. According to McCullough, the primary goal of revenge is to signal a message that will change people’s incentive to harm us. When we exact revenge, our wrongdoer will learn that their strategy is not working and will leave us alone. It is likely that our ancestry as small nomadic groups contributed to this ingroup – outgroup mentality of human social functioning. Identifying with other members of our ingroup makes us naturally suspicious of the stranger. This evolutionary history makes revenge more explicable and even makes reconciliation and compromise appear misguided and dangerous.
3. Honor cultures and revenge. Honor cultures are characterized by exhibiting revenge in response to perceived insults and threats, often through violence, even when it is very dangerous to do so. Gangs are an example of honor cultures. Members seek to restore their honor and continue to fight to defend their pride even as threats escalate. From a psychological perspective, this can be confusing: why would people choose to compromise their safety and possessions for their reputation? Dr. Todd Shackelford found that cultures of honor develop in contexts where material resources are scarce and institutions are weak. This leads people to most value their reputation, as they believe it will will promote their position in the group and ensure safety and security long-term.
4. Narcissism and revenge. Although being vengeful is not a disorder itself, people who have a high degree of narcissism are significantly more likely to engage in revenge. Dr. Leonie Grobbink and others found that the degree of narcissism of individuals is correlated with increased propensity to seek revenge. According to psychoanalytic theory, early childhood traumas are central to the development of narcissistic personality features. Cognitive theory focuses on distortions in our thinking that contribute to feeling threatened. When someone with narcissistic personality disorder is injured and engages in faulty patterns of thinking, they are at increased risk for experiencing feelings of revenge and acting on those desires to redress perceived wrongs. In fact, revenge is an intrapersonal phenomenon and the extent to which people need revenge has a certain degree of stability.
5.Revenge can be contagious. University of Maryland psychologist Michele Gelfand has studied the contagion of revenge – across people and time. When individuals identify with one another as being of the same group, an offense against one is an offense against everyone in the group. Conversely, outgroup members can be perceived as one and the same. If one member of the outgroup inflicts harm, all members of that same outgroup can be held accountable. Gelfand calls this identification and interchageablity of people entitativity. In other words, I could respond to injuries that were inflicted on someone from my ingroup and seek revenge on the perpetrator or someone from their outgroup even though I have not directly been injured. Entitativity helps explain how conflicts can escalate quickly from the individual to the group level, even across generations.
One hundred years ago, The Versailles Treaty exacted revenge. Whatever the satisfaction, it was fleeting. There is no question that we do need to reckon with wrongdoing. But the sequelae of the Versailles Treaty and the psychological research on revenge would suggest that rising above the impulse of revenge to find other solutions offers at least the possibility of more lasting peace politically and personally.