How Terrorists Think with Dr. John Horgan

One of the most important questions facing terrorism scholars and researchers is why someone becomes a terrorist or is involved in terrorist activities. Explanations and theories attempting to answer this question vary widely, from poverty to religious and political fervor. For nearly two decades, forensic psychologist Dr. John Horgan has dedicated his professional and academic career to studying terrorist psychology through countless interviews with former terrorists.

On March 13, 2025, the Program on Extremism (PoE) at The George Washington University hosted an event titled “How Terrorists Think.” The conversation included Dr. John Horgan, a Professor at Georgia State University, who was joined by PoE Research Fellow Luke Baumgartner. 

Dr. Horgan began the discussion by highlighting that the question is not why are so many people terrorists, but rather, why are so few people terrorists? He mentioned that there is no shortage of grievances and ideologies to choose from, yet the actual number of people who become terrorists is relatively few. 

Dr. Horgan also discussed three commonalities among terrorists. First, terrorists are sensitive to injustice or grievance and feel a profound moral outrage, which motivates them to act. Second, terrorists have rationalized that violent action is the only acceptable response to the injustice they face. Third, terrorists feel a sense of urgency to act now rather than later. 

He also discussed radicalization and its many pathways to becoming radicalized. Dr. Horgan identified no singular pathway and that only a few people choose to act after being radicalized. Therefore, he touched on the fact that, from a policy perspective, we, as a counterterrorism community, spend too much time focusing on decreasing radicalization and not enough time on other components of terrorism.

When asked about the differences between his research on disengagement and deradicalization, Dr. Horgan provided valuable insights into the stark differences between the two terms. He noted that disengagement is essentially a terrorist entirely stopping their involvement and pursuit of taking part in violent actions. Deradicalization, conversely, implies that a person has chosen to move away from a movement and its ideals, a particular cause, or has a change in views or perspective. He clarified that using these two terms interchangeably is a mistake that should ultimately be avoided. 

Dr. Horgan concluded by answering a few audience questions about youth involvement online, the importance, or lack thereof, prior events affecting a person’s ascension into a terrorist group, and the role of mental health in terrorism.