In 1983, when Shiite Muslims died in suicide attacks on American military barracks in Beirut, psychologists labeled them mentally unstable individuals with death wishes. Today experts agree that the acts of suicide bombers are more attributable to organizational masterminds than to personal psychopathology. Yet they continue to debate just how religion and social reinforcement transform sane human beings into sentient bombs.

Ariel Merari, Ph.D., a professor of psychology at Tel Aviv University in Israel, argues that terrorist groups such as Hamas appeal to recruits' religious piety or patriotic sentiments, but neither fanaticism nor nationalism alone are ?necessary or sufficient? to foment suicide terrorism. The key ingredient may be susceptibility to indoctrination. In a recent study of 32 suicide bombers, Merari found no illuminating socioeconomic or personality factors, such as social dysfunction or suicidal symptoms. But almost all the subjects were young, unattached males, a cohort vulnerable to violent organizations in any society.

Attempts to understand suicide terrorism are understandably culture-bound. Western media emphasize a Palestinian society awash in calls to self-destruct: Iraq and Saudi Arabia pay thousands of dollars to the families of suicide terrorists, and schools teach reverence for martyrs alongside arithmetic. Palestinian mental health professionals counter that Westerners ignore the despair inherent in this logic. Mahmud Sehwail, M.D., a psychiatrist in Ramallah, says that post-traumatic stress disorder abounds among the potential ?? and eventual ??s uicide bombers he treats and cites surveys indicating that more than a quarter of all Palestinians are clinically depressed.

But the rationale of despair is a ?double discourse aimed at Western audiences,? according to Scott Atran, Ph.D., an anthropologist at the National Center for Scientific Research in France. ?Muslims are told that these bombers have everything to live for, otherwise the sacrifice doesn't make sense.? Atran's book, In Gods We Trust: The Evolutionary Landscape of Religion, cites a recent study of 900 Muslims in Gaza who were adolescents during the first Palestinian intifada(1987 to 1993). Exposure to violence correlated more strongly with pride and social cohesion than with depression or antisocial behavior. Indeed, the Gaza teens expressed more hope for the future than did a control group of Bosnian Muslims.

Ultimately, profiling suicide bombers may be a fascinating but futile psychological parlor game. Terrorism experts such as Ehud Sprinzak, Ph.D., an Israeli professor of political science, argue that the best way to halt the attacks is not to study suicide bombers themselves, but the terrorists who press these young men and women into their last, ghastly service.