This mystery of the mind became an issue again in recent weeks as a suicide bomber in Afghanistan — a double agent — killed seven C.I.A. officers; a man plowed a truck full of explosives into a crowded playground in Pakistan, and a Nigerian man tried to blow himself up on a plane bound for Detroit on Christmas Day.
Until recently, the psychology of terrorism had been largely theoretical. Finding actual subjects to study was daunting. But access to terrorists has increased and a nascent science is taking shape. More former terrorists are speaking publicly about their experiences.
Tens of thousands of terrorists are in “de-radicalization” programs around the globe, and they are being interviewed, counseled and subjected to psychological testing, offering the chance to collect real data on the subject.