Hours after the terrorist attacks on the Charlie Hebdo offices in Paris on January 7^th, 2015, the US President Barack Obama, condemned the “cowardly, evil…and senseless attacks” perpetrated by the men who murdered twelve people. Leaders throughout the western world expressed similar sentiments. It is common for politicians to represent the perpetrators of violence as acting outside the boundaries of morality; their actions belong to an incomprehensible realm beyond our understanding of what is good and right. But the Charlie Hebdo killers were not acting at random – they were following a moral code. We don’t need to approve of their moral framework to understand that it exists and guides their behavior, and that understanding can bring us insights into the psychology of violence that we miss if we simply dismiss it as evil.

Generally speaking, we think of most interpersonal violence, not just terrorist attacks, as immoral. It’s very rare that you’ll see anybody claim that hurting someone else is an inherently moral thing to do. When people are violent, explanations for their behavior tend to invoke some sort of breakdown: a lack of self-control, the dehumanization of an “outgroup,” or perhaps sadistic psychological tendencies.

This is a comforting notion – one that draws a clear boundary between acceptable and unacceptable behavior. But according to the authors of a new book, it simply isn’t an accurate reflection of how people actually behave: morality, as understood and practiced by real-world human beings, doesn’t always prohibit violence. In fact they make the case that most violence is motivated by morality.

That’s the provocative thesis of Virtuous Violence, by Alan Page Fiske, an anthropologist at UCLA, and Tage Rai, a psychologist and post-doctoral scholar at Northwestern University’s Kellogg School of Management. Their research has led them to the conclusion, as they explained recently in New Scientist, that “across cultures and history, there is generally one motive for hurting or killing: people are violent because it feels like the right thing to do. They feel morally obliged to do it.” Those commonly invoked explanations for violence – empathy deficits, dehumanization, and simple sadism? They do play a role in violent behavior, the authors argue, but are rarely its sole triggers.

Central to Fiske and Rai’s thinking is their understanding that morality is fundamentally about maintaining the prevailing social order. Frequently that entails prohibiting violence, but at other times it actually requires it. When parents spank a child, for example, they are usually doing it to elicit appropriate behavior, and often have the child’s best interests in mind. They are generally not spanking their child because they want to do it, or enjoy it, but because they feel obligated to teach them to behave normatively, or to maintain and reinforce the proper parent-child hierarchy. Thus the familiar refrain: this is hurting me more than it’s hurting you. We may disagree with the practice of spanking, and prefer non-violent means of achieving similar ends, but we can easily understand that spanking is moral in the eyes of those who do it.

This same logic can be scaled up to truly heinous acts, like the recent terrorist attacks in Nigeria, France and Australia. Even these acts, argue Fiske and Rai, are motivated by a moral code that justifies or even requires them. When asked about the psychology behind the Charlie Hebdo killings in Paris, Rai states “that’s a case where as awful as those acts of violence are, these are cases where the perpetrators felt that they were retaliating against what they perceived to be a gross, abhorrent moral wrong.”

Fiske and Rai argue that understanding the moral nature of violence is actually essential to reducing it, because the best way to change someone’s behavior is to understand what motivated that behavior in the first place. If violence were simply based on people’s selfish desire to inflict harm on others, punishing violence would likely be an effective deterrent. But if violence is morally motivated, punishment is unlikely to be effective because, as the authors write, “people will do what is morally required if they feel their cause is righteous – whatever the consequences.”

It can be all too easy to brand violence as evil, but increasingly research is revealing this approach is too simplistic and offers no effective means of reducing violence. A similar insight is drawn by the Harvard psychologist, Steven Pinker, in his book The Better Angels of our Nature. He also argues that most perpetrators of violence throughout history are not pathological, but motivated to act within their own moral framework. Indeed, when asked about the Virtuous Violence hypothesis, Pinker reiterated a point made in his book, that “if you added up all the homicides committed in pursuit of self- help justice (i.e. taking the law into your own hands), the casualties of religious and revolutionary wars, the people executed for victimless crimes and misdemeanors, and the targets of ideological genocides, they would surely outnumber the fatalities from amoral predation and conquest.”

In Virtuous Violence, the argument is that violence is usually perpetrated by people who believe that they are doing good by the moral standards that they adhere to. Recognizing this fact offers us the best opportunity to understand the root causes of the violence and makes it possible to take steps to reduce it. Political leaders are right to condemn terrorist attacks – we do not have to accept the moral codes of others in order to acknowledge that they exist. However, long-term solutions to terrorist atrocities, as well as many other forms of violence in our society, might benefit from a taking a perspective that the perpetrators believe that what they are doing is good, just, and right.

Dave Nussbaum is adjunct assistant professor of Behavioral Science at the Booth School of Business at the University of Chicago and the editor of Character and Context, the blog for the Society of Personality and Social Psychology.

Séamus A. Power is a PhD student in social and cultural psychology at the Department of Comparative Human Development at the University of Chicago.