What Causes Terrorism? Mental Illness or Ideological Belief?

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The Equifinality of Terrorism

In an era when we’ve become all too familiar with mass shootings and terrorism both at home and abroad, and with daily exposure to reports of terrorists murdering, raping, and beheading people since the latest conflict between Israel and Hamas started two months ago, people often want to know just what it is that drives people to commit such atrocities. Meanwhile, media pundits, politicians, and casual observers alike often jump at the chance to volunteer an answer, alternately labeling terrorists as crazed fanatics, religious zealots, political extremists, mentally ill, subhuman, or just plain evil.

While we often seek simple answers to explain terrible events, research tells us that there is no one explanation for terrorist violence. There is no singular “profile” of a typical terrorist and there are few if any reliable predictors of whose anger will escalate to the point of committing acts of terror. Through the years, the field of terrorism studies has instead revealed that becoming a terrorist is an “equifinal” process, meaning that there are myriad pathways that can lead people to that endpoint.¹ Suffice it to say that ideological fanaticism, religious zealotry, terrorist group affiliation, a quest of significance, responding to “calls to action,” material rewards, a sense of grievance, unfairness, or victimhood, exhausted alternatives, and a foreshortened future can all figure into the equation. And yes, sometimes mental illness plays a role, either directly or peripherally, especially in the case of “lone actor” terrorism perpetrated by those unaffiliated with any terrorist group.^2,3

Causal Attributions of Terrorism Are Biased

And yet, terrorism research also tells us that whether or not we call someone a terrorist, fanatic, or extremist—bearing in mind the expression “One man’s terrorist is another man’s freedom fighter”—and how we alternately “explain” or attribute “blame” for terrorist violence may depend as much on ourselves as the perpetrators.

Researchers at Yale University and the University of Oslo note that we often adopt either a “blame or explain frame" for terrorism, with the “blame” frame focusing on the agency, responsibility, and guilt of a perpetrator and the “explain” frame focusing on forces beyond one’s control like mental illness.⁴ In an experiment using a “reverse correlation” study design, they demonstrated that among a small sample of White native Norwegians exposed to ambiguous images of would-be terrorists, perpetrators who were described as motivated by mental illness were perceived as more White and less Middle Eastern, whereas perpetrators whose violence was attributed to ideological beliefs were perceived as less White and more Middle Eastern. In addition, attributions of perpetrators as victims of mental illness were also associated with less perceived guilt or culpability. These findings suggest that causal attributions of terrorist behavior occur through either conscious or unconscious bias according to the race of the perpetrator and the evaluator.

A similar study reported that partisan beliefs among American and European samples also predicted whether terrorist acts were attributed to mental illness in an exculpatory fashion or blamed on “terrorist” motives by way of condemnation.⁵ When presented with real-life examples of terrorism, participants were more likely to attribute terrorist violence to mental illness when the perpetrator’s apparent ideological cause (e.g. about Brexit or immigration) aligned with that of the participants’ ideological alignment regarding that cause. These results suggest that partisan-motivated reasoning—that is, adopting biased appraisals of information to reinforce our political ideologies—can also dictate whether we play the “explain” or “blame” game when it comes to terrorism.

A third study likewise found that among those with anti-Muslim prejudices, real-life Muslim mass shooters were perceived as less mentally ill and more motivated by religion and therefore more culpable for terrorist violence compared to non-Muslim mass shooters.⁶ This held true even when the descriptions of mass shooters included descriptions of clear mental illness among the perpetrators, suggesting that both motivated reasoning and motivated denial figure into our causal attributions of terrorism to exculpatory and blaming factors.

In summary, evidence from several experimental studies indicates that we’re more likely to attribute terrorist violence to mental illness when the perpetrator aligns with our own personal identities or ideological positions. This appears to function in an identity-preserving way, allowing us to think of ourselves and our larger group identities as “good” by discounting violence perpetrated by those in our ingroups as an aberrancy of mental illness. Conversely, when perpetrators are viewed as “others,” in terms of either identity or ideology, we’re more likely to blame violence on ideological belief, with moral culpability assigned accordingly.

Justifying Terrorism Based on Victimhood

Such research supports what we’ve seen in the media over the past several years here in the U.S., with mass shootings blamed on mental illness when the perpetrator is White and the word “terrorist” applied when the perpetrator is a person of color.^7,8 We’re seeing something similar now with the political divide over the current Israel-Hamas conflict, where perceptions about which side is engaged in terrorism or is in the wrong from a moral perspective are seemingly dependent on our own identities and ideological affiliations. We’re quick to blame violence against civilians on “terrorism” when it applies to perceived others, while substituting victimhood for mental illness as a justifying explanation for it when we identify with the perpetrators.

If racial biases and motivated reasoning are influencing our perceptions of terrorism in this way, how can we better understand and discuss terrorist violence in a more objective fashion? For one thing, we can condemn violence against civilians without allowing ourselves to find justifications for it. We can also reject the notion that terrorism can be so neatly explained by ideological belief on the one hand and something like mental illness or victimhood on the other. It’s a lot more complicated than that, at the level of both individual perpetrators and the bigger picture of geopolitics.