Robert Pape has been building databases of terrorists for a while now. The University of Chicago's CPOST (Chicago Project on Security and Threats, which Pape, a professor of political science at the university, directs), hosts the Suicide Attack Database, which contains information about every suicide attack from 1982 through June of last year—5,292 attacks in 40 countries over 34 years.

Pape's latest database covers something closer to home: The American Face of ISIS. It's a comprehensive database that gathers all 112 ISIS-related offenses in the United States from March 2014 through August 2016. There were three types of offenses: attacks, traveling overseas to fight for ISIS, and providing material support to the group.

And putting the database together brought some surprises for Pape.

"Before I did this, I had a lot of the impression that a lot of folks in the public … and the Trump administration have—which is that overseas terrorist groups were trying to get at us by continuing to exploit cracks in our immigration procedures. There is a bit of that, [and] that is the way that the 9/11 hijackers got in," Pape says. "What I didn't realize is how much that picture has changed in the last three years with ISIS in particular."

His data show that the vast majority of people who committed ISIS-related offenses in the U.S. (64 percent) were American citizens by birth.

Furthermore, two of the three refugees on the list are Bosnian refugees who came to the U.S. in 1999; the third was an Iraqi refugee who came to the U.S. in 2012, traveled to Syria, joined a group that later joined ISIS, and was arrested upon his return.

"ISIS really seems to have learned that we have dramatically improved and sealed many, many cracks in our immigration procedures. What you see with the systematic analysis and tracking of the ISIS terrorists since March 2014 is that they're overwhelmingly homegrown," Pape says.

These people are not just homegrown, but pretty normal, at least by socioeconomic measures. For the cases in which this information was available:

  • 42 percent were in a relationship at the time of arrest
  • 33 percent were married
  • 72 percent attended some college
  • 18 percent have a bachelor's degree or attended grad school
  • 77 percent were in school or had jobs
  • 23 percent were unemployed

"Once you control for the age cohort, they're surprisingly normal with respect to their relationships and partnerships, much closer to the norms in American society than you would see in this anecdotal presentation we often see of one or two super-hyper loners. That's really a striking finding," Pape says.

A substantial minority, 30 percent, are "known converts," which the report describes as not "from established Muslim communities, don't have family or cultural ties to the Middle East, and are unlikely to have longstanding grievances related to the region." Forty-three percent of the U.S.-born indictees fall into this category, as do 51 percent of attackers (as opposed to travelers or facilitators).

Some were fairly recent converts—converting less than a year before they were charged, Pape says. Those cases might suggest that their primary motivation was not related to Islam itself, but rather "they're attracted to the politics of ISIS," he adds.

"What you see is even more than we've seen in the past, ISIS terrorists coming from a wider range and multiplicity of backgrounds," he says.

What's driving the recruitment of these U.S.-born converts, who are likely quite Westernized? Pape and his colleagues' found that eighty-four percent of the indictees were exposed to "extremist propaganda videos. Eight-six percent of that group consumed specifically ISIS-made videos, and 53 percent were exposed to the notorious execution videos."

The research group honed in on these videos: To appeal to Westernized potential recruits, ISIS borrows Western culture—not just production values, but narrative arcs.

"What we're starting to see is powerful narratives that are in major movies, blockbuster movies, that may be doing quite a bit of the work here, separate from the glitz and the glam. That's one of the big things to pay attention to. Terrorists are not rejecting Western ideas," Pape says. "In the old days—I've been studying this now for a long time—what you typically saw from Al-Qaeda, or Hezbollah, or Hamas, was a wholesale rejection of anything Western. Not an adaptation of something Western to hurt us."

It's what researcher Javier Lesaca calls "marketing terrorism"; in an analysis, Lesaca found that 15 percent of ISIS videos released in the course of a year and a half "are directly inspired by real films, videogames, and music video clips of contemporary popular culture, such as the films Saw, The Matrix, American Sniper, and V for Vendetta; or videogames like Call of Duty, Mortal Combat X, and Grand Theft Auto. The terrorist group uses cultural images of modernity in order to promote a political project based on anti-modern values."

Pape is going to push this analysis even further through a collaboration with Jean Decety, a University of Chicago neuroscientist whose research on empathy and psychopathology I've written about before. Much of Decety's work focuses on where emotions are rooted in the brain and what areas are stimulated by inputs that we commonly associate with emotions—like videos. So Pape and Decety are showing those propaganda videos to subjects of different kinds in order to get a quantitative angle on what is otherwise a qualitative, self-reported question: why do these work so well?

"[American law enforcement] has black-belt whizzes in social media and the internet, we have enormous depth there. What we're missing is the social-science part. That's really the new knowledge that needs to be created," Pape says. "The FBI has been paying attention to that terrorism-related research. This is what is being used by the FBI to help prioritize and surveil. They have been among the biggest consumers of that social-science research, and it's really paying off."