Terrorists who kill themselves for their cause are murderous and often misguided - but almost never crazy.
The discipline and preparation required for such an act renders the mentally unstable poor candidates, according to psychologists and others who have studied suicide warriors throughout history. And the teamwork required - authorities say at least 19 were involved directly in the four hijackings last week - rules out most forms of sociopathy.
As distasteful as it seems to Western sensibilities, the psychological profile of a suicide terrorist more closely resembles that of a fanatical soldier or idealistic hunger striker than a lunatic killer.
"They are not crazy. It would be more comforting to us if that were the case, but it's not," said Martha Crenshaw, a professor of government at
who specializes in political terrorism and political psychology.
"Some individuals who do this might be distraught and disturbed. Some may see it as an opportunity for suicide," Crenshaw said. "But it generally has a lot more to do with the psychology of the group."
Recent studies of suicide attackers show a range of backgrounds and demographics. Most tend to be young, unmarried men with limited prospects for a career. But there are exceptions.
Tamil separatists in Sri Lanka, who have carried out more suicide attacks than any other group in modern times, often use women. Likewise, Kurdish rebels in Turkey pack explosives around the midsections of women volunteers so they appear pregnant and are spared body searches. And the Arabic men who piloted the jetliners to their fiery ends last week over the United States were mature and, in at least one case, married and would appear to have had valuable job skills.
"They are as rational as you or I," said Rohan Gunaratna, a research fellow at the Centre for the Study of Terrorism & Political Violence at Scotland's University of St. Andrews. He has interviewed suicide bombers who were caught before they could pull the trigger and warns against drawing sweeping conclusions about their psychological or demographic backgrounds.
The roots of self-destructive soldiering goes back at least to early Persia, in the 11th century, when lone Muslim fighters launched dagger attacks on Christian Crusaders knowing they themselves would be quickly killed. The sect responsible for the attacks was thought to smoke hashish and came to be known by the Arabic word for hashish user, hassasin, from which the English word assassin evolved.
There was a famous case in 17th-century Japan of 47 followers of a disgraced feudal leader, or shogun, launching a retaliatory raid. These ronin, or dispossessed samurai, then killed themselves ritualistically in accordance with shogun law.
In modern times, the use of suicide attacks has been associated almost exclusively with desperate causes, said Andrew Silke, a forensic psychologist at the University of Leicester in the United Kingdom who has studied terrorism.
German pilots resorted to ramming their planes into bridges on the Eastern Front in a frantic and futile effort to stop the advancing Russians at the end of World War II. Similarly, the Japanese resorted to kamikaze raids when their nation was down to a skeletal air force and facing imminent Allied invasion.
"They saw what they were doing as an act of sacrifice to protect the homeland. You see the same thing by these Palestinians against Israel," Silke said.
Use of suicide terrorism in the Middle East resumed in the 1980s. During its 1980-1988 war against Iraq, Iran dressed teen-age boys in burial shrouds, promised them martyr status and sent them to their deaths in human wave assaults. The first of several suicide bombers appeared in Lebanon in 1981 to protest the Israeli invasion and occupation. Among the early victims: 239 U.S. service members killed in 1983 by a truck bomber amid their barracks in Beirut.
Many Islamic clerics opposed the tactic as a violation of their faith, but it proved effective, and its use spread.
The Sri Lankan Tamil Tigers, a largely secular group fighting for a separate Tamil state, launched its first suicide attack in 1987. Elite suicide warriors, equipped with cyanide capsules for use in the event of capture, conduct regular raids against high-profile targets. In 1991, a Tamil woman suicide bomber assassinated former Indian Prime Minister
Gunaratna has identified 10 groups actively using suicide as a weapon: two centered in Israeli-occupied lands, two in Egypt and one each in Lebanon, Algeria, India, Sri Lanka, Turkey and Afghanistan. He estimates that 280 to 290 suicide terrorist missions have taken place since 1981, and predicts the frequency will increase in coming years.
"It is a low-technology, high-impact operation," he said.
Silke said the Palestinian bombers who have spilled so much blood in Israel in recent years are 85 percent male, usually about 20 years old and lacking in solid job prospects. They tend to be unmarried, childless and often come from an unhappy family background. They almost always have suffered a recent "triggering event," such as the death of a close friend or relative at the hands of Israel's armed forces, he said.
"The groups always turn these people away, knowing their anger will cool down. It's only after you keep coming back that they will take you in," Silke said.
Candidates showing obvious signs of instability are rejected as too risky. Those accepted undergo training and extensive indoctrination. Often they are given assurances that their families will be cared for and that their efforts will help their group and win the terrorist special access to heaven in accordance with Islamic beliefs about martyrdom.
"They believe they are making a sacrifice for a greater good. In their eyes, there is something noble about what they are doing," Silke said.
Gunaratna said the characteristics that attract someone to a suicide mission are not necessarily the same as those of a terrorist leader or radical group operative. He quoted a Tamil leader's handbook, which said a suicide fighter must possess "a mind like steel but a heart like the petals of a flower."
"They are living in a very controlled environment. They are naturally brainwashed by the organization," he said.
Recruits are subject to intense indoctrination, usually one-on-one with an assigned operative. They consider their missions as acts of martyrdom, not suicide, a distinction that is difficult for Westerners to comprehend, he said.
They come to view human and inanimate targets as interchangeable, he said.
"They have seen so much of life being lost they lead such Spartan lives," he said. "If you are less worldly, and have less to lose, you are more likely to do this."
Crenshaw said the training and indoctrination have parallels in what military recruits undergo in boot camp. Their sense of self and individuality are subordinated as their identity is merged into the identity of the group, she said.
Similarly, suicide terrorists come to view their lives as expendable for the good of the group.