The 19 men who carried out the Sept. 11 attacks may have been motivated by a force more powerful than religious zeal or hatred for the United States: Peer pressure, according to psychological experts who have analyzed the backgrounds of the terrorists.
Although only sketchy information is available about most of the men, it's become increasingly clear in the four weeks since the attacks that the terrorists did not meet the profile of the prototypical suicide bomber -- young, uneducated, poor and disaffected.
A number of experts who have analyzed what is known about the men and studied the long history of suicide bombers that precedes them have concluded that the roots of the attacks lie less in the men's personalities and beliefs than in group psychology.
"The power of the group over the individual is what's important," said Martha Crenshaw, a professor at Wesleyan University who studies political psychology and terrorism. "People may be more loyal to the group than the cause. The cause is long-term; the group is tangible."
Some of the Sept. 11 hijackers appear to have been extremely religious, leading to speculation that they may have committed their acts as part of a religiously motivated "jihad," believing that as martyrs a paradise awaited them in the afterlife.
While those beliefs may have played a role, psychologists, psychiatric profilers and terrorism experts who have been studying the Sept. 11 attacks -- including some experts who have worked in law enforcement or consulted with the federal government on national security issues -- said religious zeal isn't necessary to become a suicide bomber, and cannot by itself explain the behavior.
"Two thirds of [suicide] attacks in Lebanon were carried out by secular organizations," said Ariel Merari, a psychologist at Tel Aviv University in Israel who has puzzled over the psychological makeup of the Sept. 11 hijackers and has spent years studying suicide attacks around the world. "Religion is neither necessary nor a sufficient cause."
"Suicidal terrorist attacks are not a matter of individual whim," said Merari. "I don't know of a single case in which an individual decided on his or her own to carry out a suicidal attack. In all cases -- it certainly is true in Lebanon and Israel and Sri Lanka and the Kurdish case -- it was an organization that picked the people for the mission, trained them, decided on the target, chose a time, arranged logistics and sent them."
The role of group dynamics may have played an especially important role in the Sept. 11 attacks because they were far more complex than strapping on a backpack of explosives and walking into a pizza parlor, or driving a truck laden with explosives into an enemy building. The terrorists had lived for weeks, months or even years far from the main groups that had inspired and chosen them. They had to blend in with their neighbors as they learned to fly large commercial planes at U.S. flight schools, acquiring drivers' licenses and booking airline tickets over the Internet.
"These people were living in the midst of Western life. No beard, no Koran, and yet they carry with them laser-like beams focusing on their ultimate missions. I see them as fully formed psychological adults who have subordinated their individuality to the group," said Jerrold Post, a former CIA psychological profiler now at George Washington University.
Because the desire to participate in high-risk or suicidal missions fluctuates with time, said Merari, suicide attackers are usually sent hurtling toward their targets soon after they are selected and indoctrinated. Most groups do not allow prospective attackers to mingle with anyone outside the group's inner circle before an attack -- certainly not with the "enemy."
"With all the groups who are willing to kill themselves . . . they have yielded their authority to the group. They will give their lives to the group," said Post, who has served as a government consultant on national security matters.
One of the reasons for the large number of hijackers involved in the Sept. 11 mission may have been the extension of this group psychology -- the hijackers reinforced each other's beliefs and deterred an individual who wanted to back out at the last moment: He would have not only faced the wrath of the shadowy leaders who planned the operation, but would have been letting down his immediate circle of friends, peers and comrades. Groups that prepare suicide attackers are keenly aware of this psychology.
"I see [Mohamed] Atta as [like] a coach before the big game. He has them pray a lot to keep their minds on what they are doing," Post said.
Many organizations make recruits videotape their intentions, and are told that the videotape will be released to their families and the public after the attack, Merari said. Backing out of the operation now becomes difficult, and besides the fear of retaliation from the group, comes the prospect of shame and dishonor.
"Suicide candidates, when they are chosen by an organization, enter into one end of a production process and in the other end they come out as complete, ready suicides," he said. "There is a psychological process of preparation that consists of boosting motivation, pep talks and the creation of points of no return."
The Sept. 11 hijackers wrapped themselves in each other's company. They traveled together, planned together, ate together. Even when they partook of Western temptations -- bars, drinking and pornography -- they probably reinforced each other's contempt for America, said Washington psychologist Rona Fields, much like men who "go to strip shows and get involved with prostitutes but have tremendous contempt for women."
The group psychology tactics, said the experts, are an extension of military preparations. Soldiers join armies to fight for king, God and country, but soldiers under fire fight to the death for their buddies in the nearby trenches. Whole regiments in World War I have been immortalized for charging artillery positions, knowing that death was certain. Japanese kamikaze pilots in World War II wrote notes before their missions saying they hoped that by crashing a plane into a U.S. ship they would slow the allied advance by a single day and bring honor to themselves and their squadrons, said Mako Sasaki, a Washington area researcher.
Most modern groups that rely on terror have similarly astute psychological training: The Tamil Tigers have suicide recruits compete to be chosen for missions. The "winners" eat "celebratory" final meals with the charismatic leader of the movement -- and photos of the celebrations are later released to local magazines. Merari said he thought it was likely that the 19 hijackers of the Sept. 11 attacks had made such formal commitments.
The fact that the Sept. 11 terrorists did not fit the usual profile makes tracking terrorism more difficult, experts said.
"This is what I'm increasingly afraid of," said Ehud Sprinzak, dean of the school of government at the Interdisciplinary Center in Herzliya, Israel. If educated, older men could "go into the suicide cycle, why not professors, doctors, lawyers who go through conversion and become very, very committed? . . . It's going to be increasingly difficult to characterize psychologically."
Some experts suggested the answer, again, may be found in studying the groups that produced these individuals, because they are more identifiable.
Fields, who has studied the Sept. 11 attacks and suicide terror movements in Palestine, Israel, Lebanon, Northern Ireland and South America, said groups on the fringes of societies -- both abroad and in the United States -- offer an opportunity for the desperate to feel good about themselves.
"One of the things that typify high school kids and gangs is they have to be with their identity groups in order to feel vindicated and reinforced," she said. "If you take militias that operate in the U.S. -- like Tim McVeigh's bunch, what you find is they engage in only one kind of [social] interaction. That is their vocation, their avocation, their social life, religious life, everything."