'You don't look at their face, even when you put prods in their mouth," a Chilean torturer said in 1984. "You keep their eyes covered. The secret is not to look into their eyes. The other secret is not to draw blood. You leave that for the sick bastards or the young brutes. You can watch the body arch and bounce under electricity, but never draw blood." His words are ruthless and chilling, even monstrous, although he is clearly no monster. There is an obvious humanity in his thoughts. Like an ordinary person, this man is repulsed by torture. Like an ordinary person, he takes no pleasure in it and he scorns the "sick bastards" who do. But unlike ordinary people, this man obeyed the orders of superiors, deliberately overcame his own decent instincts, and tortured helpless human beings. Adolf Eichmann was also no monster. He was a perfectly ordinary bureaucrat, passionate about little except efficiently accomplishing whatever tasks were assigned to him. During the Second World War, the task assigned to him was to deal with the logistics of murdering millions of people and as a principal architect of the Nazi death-camp system, he did so efficiently. Watching the trial of this bland little man, philosopher Hannah Arendt had a revelation: Far from being monstrous, evil is often banal. Arendt's phrase, "the banality of evil," has so penetrated the culture it has become a cliche, and yet it's questionable whether we really understand and accept the ramifications of this idea. It's deeply unsettling to think that ordinary people can commit great evil. We prefer to believe that killers are beasts, not like us. And torturers are something stranger still. Torture is the most intimate of crimes. The torturer always gets close to his victim, physically and psychologically, sitting with him, like doctor and patient, sometimes drawing so near he can feel the heat of the victim's gasps. The torturer talks with his victim for hours and days. Even for weeks and months. He seeks to know the victim, to find his weaknesses and fears, to learn what will break this man. And he does all this while inflicting on the victim suffering so profound it can scar the soul. How could anyone be capable of such a crime? They must be sick, we assume. Twisted. They must be empty of normal human feeling. They must be sadists. Hateful madmen. Monsters. In reality, Arendt's dictum about the banality of evil applies particularly well to torturers. They are men like the Chilean who couldn't look into his victim's eyes. Torturers are men like Alfredo Artiz, a notorious Argentine who was described by one of his victims as "an English gentleman." Or the Greek officer who ultimately married a woman he once had tortured. Torturers, in short, can be almost anyone. What matters is not the person, say experts who have studied those whose job is to make prisoners suffer. What matters are the circumstances surrounding the person. If they come together in the wrong combination, "all of the research shows most people will do things that they cannot imagine doing," says Philip Zimbardo, a psychologist at Stanford University and a co-author of Violence Workers, a book based on extensive interviews with Brazilian torturers and assassins. Mr. Zimbardo and other researchers in this dark field think the lesson of Adolf Eichmann is particularly urgent today, as soldiers and intelligence officers from the United States and other western countries fan out across the globe in the war on terror. As they arrest and interrogate suspects, they will likely find themselves in precisely the sort of circumstances that make ordinary people inflict torture and they, like countless ordinary people before them, will inflict torture. It may already have happened. And it will continue to happen if governments do not guard against it. Of course, we don't like to imagine that we, or those who work for us, could do such a thing. But as journalist John Conroy wrote in surveying the history of torture from ancient times, there is a recurring theme: "It is easy to condemn the torment when it is done to someone who is not your enemy, but it seems perfectly justifiable when you perceive a threat to your own well-being." It's hard to imagine a worse atrocity than that committed by German Reserve Police Battalion 101 during the Second World War: The shooting of 38,000 Jewish men, women and children. And yet when historian Christopher Browning studied the men who lined up their victims next to open pits and pulled the triggers, he found they were mostly middle-aged civilians. They had families. They had normal emotions. Hesitation and dissent were widespread, at first. When the battalion commander first told his men what they were to do, he expressed disgust; he had tears in his eyes. These men were mass murderers, but they were also, as Mr. Browning put it in the title of his book, Ordinary Men. John Steiner, a sociologist and Holocaust survivor, interviewed hundreds of Nazi concentration camp guards. He came to the same conclusion. When Eichmann left his office and visited a concentration camp, he was sickened. So was SS chief Heinrich Himmler when he inspected a mass execution. In a private speech, Himmler implicitly acknowledged the ordinary human feelings of his officers and lauded them for pushing those feelings aside. "Most of you know what it means when 100 corpses are lying side by side, or 500, or 1,000. To have stuck it out and at the same time -- apart from exceptions caused by human weakness -- to have remained decent men, that has made us hard. This is a page of glory in our history which has never been written and is never to be written." Historian David Chandler studied the genocidal regime of Pol Pot in Cambodia and came to remarkably similar conclusions to those who studied Nazi atrocities. In particular, Mr. Chandler examined the operation of "S-21," a notorious Khmer Rouge torture facility, and found no evidence that those who ran the machinery of pain were in any sense abnormal. In Greece, psychologist Mika Haritos-Fatouros studied a torture unit that operated under a military junta between 1967 and 1974. Again, she found nothing unusual about these men. In Violence Workers, the three co-authors interviewed 14 Brazilian torturers and assassins. In summing up the results of this research, Philip Zimbardo echoes Mr. Browning's description of the Nazi death squad: "These are, essentially, ordinary men." Mr. Conroy examined torture in Northern Ireland, Chicago and Israel and summed up his findings, and perhaps the whole subject, in the title of his book: Unspeakable Acts, Ordinary People. Clinical experiments provide further evidence that evil can come from the most unlikely sources. In the Stanford Prison Experiment of 1973, Mr. Zimbardo, a past president of the American Psychological Association, had university students play the roles of guards and inmates in a prison-like setting where the power of the guards was almost absolute. All participants were screened. "We purposely took people who were normal because we wanted to be sure that they were not bringing any pathologies into the experiment," says Mr. Zimbardo. "We wanted to see what prison does to ordinary people." Very quickly, some of the guards became terribly abusive, while the rest kept quiet about the abuses and went along. Prisoners became passive and submissive, and some suffered emotional trauma. The experiment, which was scheduled to last two weeks, had to be shut down after just six days. Shocking Experiment A decade earlier, Yale University professor Stanley Milgram conducted a classic series of experiments that came to an equally bleak conclusion. In its most basic form, Mr. Milgram's project involved a lab supervisor, a learner and a teacher. The teachers were drawn from student volunteers, who were told the experiment was designed to test the effect of punishment on learning. The teacher sat in front of a control panel with 30 switches that delivered electrical jolts in escalating amounts. The first switch was 15 volts, the last 450. The four switches from 15 to 60 volts were marked "Slight Shock," then came "Moderate Shock" and so on until the final two clusters of switches marked "Danger: Severe Shock" and "XXX." The experiment seemed simple enough. The teacher asked the learner a question. If he got it wrong, the teacher announced the voltage level of the switch -- starting at the bottom end -- and hit it, giving the learner a jolt. Then the process was repeated using the next switch on the scale. In reality, the teacher was the unwitting subject of the experiment, while the learner was simply an actor pretending to be zapped. The experiment was designed to answer a simple question: Would ordinary people voluntarily inflict pain on an innocent stranger at the direction of an authority? Mr. Milgram expected few would. He was wrong. In the first trial, in which the learner was placed in a separate room and could only communicate by banging the wall, almost all the teachers kept hitting the switches right into the zone marked "Extreme Intensity Shock." Almost two-thirds obeyed right to the end. In the second trial, the teacher could hear the learner's screams and pleas to be let go. Again, two-thirds of teachers obeyed to the end -- even though they began to show signs of stress, such as sweating and nervous twitching. "In observing the subjects in the obedience experiment," wrote Mr. Milgram, "one could see that, with minor exceptions, these individuals were performing a task that was distasteful and often disagreeable but which they felt obligated to carry out. Many protested shocking the victim even while they were unable to disengage themselves from the experimenter's authority. Now and then a subject did come along who seemed to relish the task of making the victim scream. But he was the rare exception, and clearly appeared as the queer duck among our subjects." Mr. Milgram also asked 110 psychiatrists, graduate students and undergrads to predict how ordinary people in the experiment would perform. Without exception, respondents said virtually everyone would refuse to obey the supervisor at some point, and only a pathological fringe of one or two per cent would go to the end. Mr. Milgram's experiments are often taken to mean that most of us will always be obedient to authority, but that's not quite right, says Martha Huggins, co-author of Violence Workers and a sociologist at Tulane University. She notes that Mr. Milgram conducted many different variations of the experiment, and in some trials the rate of obedience dropped. This is critical to understanding what makes an ordinary person do evil, she says. "When the experiment was done by Stanley Milgram in a white coat at Yale University, where he would look face-to-face with people in this respectable setting, you had the highest levels of obedience to authority. When it moved to a storefront in New Haven, you had lower levels of following authority. And when the order came over the phone, you also had a drop in obedience. So what that tells us is, yes, we do follow authority, but there are situations that can be created that will make it more probable that you'll carry out the bad act and situations that can make it less probable." Philip Zimbardo calls it "the power of the situation." Even small environmental cues can carry great weight -- Mr. Milgram's white lab coat, for example, suggests the wisdom of science, particularly in a laboratory on the Yale campus. These cues shape how the would-be torturer sees what is happening. "It's all about psychology. It's about transforming your thinking about who you are, about what you're doing and about who you're doing it to." The observer may see a man cold-bloodedly torturing a victim, but that man sees himself, his actions, and who he's doing it to very differently. The transformation never happens suddenly. "You have to desensitize people to something that is ordinarily aversive or horrific," says Mr. Zimbardo. In Mr. Milgram's experiments, teachers were told to start with switches labelled "Slight Shock" and there was little reaction from the learner. Only after the eighth switch was thrown did the learner complain the jolts were painful and only after the 10th switch did the learner demand to be released. A similar transition period happened in Greece, where recruits for the torture unit studied by Mika Haritos-Fatouros were first taken through a months-long training program in which they were subjected to much of the same abuse they would later inflict on others. Such formal training of torturers is rare, but everywhere torturers are only slowly introduced to their new craft. Attila, a 36-year-old Turk, says that on one of the two occasions when he was tortured, "they had a trainee and they were giving him lessons." In this particular class, the trainee was shown how to twist a man's testicles without leaving evidence of torture. In Brazil, says Mr. Zimbardo, new recruits would "first observe a small group of senior torturers torturing somebody. Then you join what they called a tea party, three or four who are inflicting torture on this guy." Then the torturer would be ready to work alone. Ideology is an essential element in the progression to torture. "I can't imagine a system of gross human rights violations where there isn't some kind of ideology that justifies it," says Ms. Huggins. Hollywood villains may revel in their wickedness, but ordinary people have a core need to believe they are good. Ideology allows them to rationalize their awful acts so they can continue to believe in their own goodness. The Germans of Battalion 101 relied on anti-Semitism and German nationalism. Greek and Brazilian torturers considered themselves patriots defending their countries from Communism. Even the Milgram experiments played off our ideological faith in science, says Mr. Zimbardo. "So it started with a very positive ideology. You want to help people. You're not a bad guy, you're a good guy. You're the teacher." Dehumanizing the Victim Another element almost always found in torture is dehumanization. For a ordinary man to torture, he cannot fully see and accept the victim's humanity. This is why the Chilean torturer advised against looking into the eyes of victims; it's also one reason why most torturers worldwide put blindfolds or hoods on their victims. Mr. Milgram discovered this basic rule when he ran a variation of his experiment in which the learner was seated just a few feet away from the teacher -- the obedience rate dropped from 63 per cent to 40 per cent. Language is a vital tool in dehumanization. "You're not torturing men and women," Mr. Zimbardo says. "You're torturing socialists, communists, homosexuals, enemies." Nazi propaganda called Jews "vermin" and bureaucrats like Eichmann processed "units." Torturers routinely insult their victims -- pig, bitch, monkey, faggot, whore, nigger -- not only because this hurts victims, but because it confirms the victim is bad, low, guilty, immoral, sub-human. Perversely, torturers may feel compelled to further degrade the victim after torture. In his experiments, Mr. Milgram was surprised to discover that "many subjects harshly devalue the victims as a consequence of acting against him. Such comments as 'He was so stupid and stubborn he deserved to get shocked' were common. Once having acted against the victim, these subjects found it necessary to view him as an unworthy individual whose punishment was made inevitable by his own deficiencies of intellect and character." Language is also helpful in denying the plain reality of what is happening. In German death squads, mass murder was "cleaning" and "making order," while official tallies of their handiwork listed the dead as "partisans" even if the victims were unarmed women and children. Similarly, torturers rarely say they torture. They say they interrogate, question, punish, isolate, give "the third degree," or some other euphemism. But they don't "torture." Even long after they have left violence behind, they avoid the word. In Violence Workers, the authors describe an interview with a Brazilian named Sergio who had frequently tortured prisoners, but still "seldom used the 'T-word,' usually waltzing around or mislabelling it." At one point, Sergio vehemently insisted he "never used violence against anyone in the Communist party" and then described how he almost beat a student "to death" when the student denied being a Communist. A more sophisticated evasion was used by the Chilean who wouldn't look his victims in the eyes. He never tortured anyone, he said, because "torture is inflicting pain for personal pleasure. I dealt punishment to my enemy under orders from my superior." Obviously, these denials are flimsy dodges that wouldn't stand up to the slightest reality check -- even conversations with friends, family or officers not involved in torture would likely expose the deluded torturer to the truth. But that outside scrutiny rarely happens. Torturers and assassins often work in highly specialized, secretive, unsupervised, isolated units. The Greek torture unit, for example, was treated as elite within the military but one so detached and unique -- members didn't even have to wear uniforms -- that it was its own little society. Much the same was true of Brazilian torturers and killers, says Martha Huggins. "Some of the guys in the specialized units would be on the road for two or three weeks at a time. They're not interacting with family or friends, not involved in the repressive apparatus. The only people they interact with are specialized police in that system. So, they have no reality check." There's yet another layer of self-deception in the torturer's mind. "Somebody is responsible for different elements and therefore nobody is responsible for it," says Ms. Huggins, who once asked a Brazilian police officer if he had ever killed anyone. "He said, 'There were many operations where we were all shooting, but I don't know who did the killing. Somebody killed, but I don't know if it was me.' " This quirk of human psychology has traditionally been used with firing squads, where all the shooters but one are given blanks so that no one knows which rifle held the deadly bullet and no man feels personally responsible for causing the death. "It is psychologically easy to ignore responsibility when one is only an intermediate link in a chain of evil action," wrote Stanley Milgram. Torture almost always involves this diffusion of responsibility because torture is almost never decided on and carried out by one person. Instead, those higher up give tacit support, someone else gives the order, others arrest the victim, different people beat him, another gives him electric shocks, someone else asks questions, and so on. Brazilian torturers put great stock in the fact that "someone else arrested the guy, or someone else applied the electricity. Interrogators would say, 'I only asked the questions,' " notes Ms. Huggins. "That's why it's so important to see this as a system." Even more perversely, torturers often push some of the psychological burden onto the victim. One Brazilian interviewed by Ms. Huggins was still angry with a woman he had tortured because, he complained, if she had co-operated, he wouldn't have had to do it. Just Following Orders Separately, the factors on this long list are of little consequence. But in combination, they are a witch's brew capable of producing a profound psychological transformation. An observer sees a man cold-bloodedly torturing a victim. But in his mind, the torturer is sure he's a decent man. He is doing difficult but noble work. He is fighting dangerous, sub-human enemies. And anyway, he is only following orders. "The trouble with Eichmann was precisely that so many were like him, and that the many were neither perverted nor sadistic, they were, and still are, terrifyingly normal," wrote Hannah Arendt. "This new type of criminal commits his crimes under circumstances that make it well-nigh impossible for him to know or to feel that he is doing wrong." This lesson urgently needs to be heard and understood in this time of war against terrorism, says Mr. Zimbardo. The Brazilian torturers he interviewed committed their crimes "in an ideology of fear, much like the ideology that exists in the United States now," says Mr. Zimbardo. "If you declare 'This is a national emergency, this is national security, we have to identify enemies of the state and deal with them by all means possible,' torture may be one of those means." Ms. Huggins also worries the other ingredients of torture may be in place. The military and intelligence units that interrogate terror suspects are deeply secretive, independent, hierarchical and specialized. They use a language saturated with euphemisms like "collateral damage." And they could easily dehumanize suspects whose looks, speech, dress and prayer are alien. The particular torture methods commonly alleged to be used by American officials, "stress-and-duress" techniques, would be particularly well-suited to deluding torturers about what they are really doing. First, there's the popular misconception that stress-and-duress techniques -- restricted sleep and food, constant noise, awkward positions, sensory deprivation -- do not really cause deep suffering, so they can't be called "torture." And each method seems quite benign in itself, at least in the early stages -- what does a little sleep-deprivation matter? Perhaps most importantly, most stress-and-duress techniques don't require the torturer to actually do something to the victim. Rather, the torturer must not do something -- don't give him food, don't remove the hood, don't take him out of the cell. It would be relatively easy for a torturer to convince himself he wasn't doing much of anything to the victim at all. All this leaves one critical question, Ms Huggins says. Are those on the front lines "part of a larger system that's promoting and excusing torture?" Are those higher up the chain of command watching carefully and stopping interrogations that cross the line, or are they tacitly condoning torture by turning a blind eye? In December of 2001, the Washington Post published the first of many articles quoting intelligence sources who claimed American officials routinely use interrogation techniques that arguably constitute torture under international law. But just as importantly, the story revealed an alarming attitude among those in power. "Without exception," the Post reported, "the current national security officials interviewed for this article defended the use of violence against captives as just and necessary." "I worry a lot about this ideology of terrorism and the free rein we've been forced to give agencies that spy on us, agencies that interrogate and investigate, and how this could turn out," says Ms. Huggins. "We have to remember the words of Hannah Arendt."