Ariel Merari, a Tel Aviv University psychologist who has specialized in the study of terrorism for 40 years, can help us understand a little more. He believes most suicide bombers are introverted, inhibited loners who lack self-confidence, have trouble making decisions and rely heavily on the opinions of others. They are anxious to please. Usually they don’t belong to a terrorist organization till they are recruited for suicide. Aside from studying reports of terrorism from around the world, Merari has in recent years headed a unique research project in Israeli jails.