Why are they smiling?

The camera doesn't lie, but it does raise a troubling question: As human beings are treated like animals, why is this "girl next door" smiling?

That question continues to haunt a disbelieving American public which in April gasped to see a photo of GI Lynndie England cheerily leading around a naked Iraqi prisoner on a leash at Abu Ghraib prison. Apparently ordinary guys, too, posed - with smiles - beside men they'd allegedly beaten and piled high in a pyramid to get them to talk. Just following orders, some said, yet the question remains: Why such happy faces?

Psychologists, theologians, and a journalist who researched war for years hold that, under certain conditions, otherwise ordinary people can be susceptible to adopting a warped mentality in which they take pleasure in another's suffering - also known as sadism.

What, exactly, causes some people to engage in sadistic behavior is something of a mystery, they say. But most cite the strangeness of a war zone, where otherwise honorable people - awash in feelings of duty, camaraderie, and revenge - sometimes lose the moral compass that guided their behavior in their former lives.

Two main theories abound on such cruelty: One is that war can make good people callous, even sinister; the other is that everyone already is a bit cruel, and war just tends to bring out the worst of it.

The fiery emotions of war and a foreign environment can conspire to lower moral inhibitions, says one psychologist who has studied people's justifications for evil and violent behavior. In extreme cases, they may even transform honorable young men and women into hardened characters who can induce pain without remorse.

"Personalities can become quite different," says Arthur Miller, a Miami University (Ohio) social psychologist and editor of the new book "The Social Psychology of Good and Evil." "As you victimize other people, you convince yourself you're doing a good thing or else you go crazy. When this person returns, their families in fact are not seeing the person they knew."

Others, however, say extreme conditions can bring to the fore irascible tendencies common to some young adults, and the mission in war - to get the job done - might at times cause a certain degree of sadism.

"You've got to see the enemy as less than human," says Lance Morrow, a former Time Magazine journalist who interviewed Serbian warlords for his 2003 book "Evil: An Investigation." "Glee expresses your power. The glee evident at Abu Ghraib is part of a parading of power over powerlessness. It's aimed at breaking down the suspect by giving them a sense of powerlessness.... [But] glee in wartime also covers up fear."

Mr. Morrow regards soldiers' conduct at Abu Ghraib as "terrible" and "stupid" but not "evil," since he says these humiliation tactics hardly rival the ruthless killing sprees he observed in Rwanda or Bosnia in the 1990s. In fact, stories of warriors who enjoy inflicting torture have dotted accounts from Attila the Hun to Adolf Hitler, although the spying eye of a camera - and its strange ability to forge a smile anytime - is relatively new.

Nonetheless, incidents documented at Abu Ghraib do constitute "sadism," according to other sources for this story, and might shed light on a seldom-studied side of human behavior.

As for the ordinary person's propensity for sadism, psychologists have no choice but to cite studies dating from 25 years ago. That's because ethical regulations have for decades prohibited researchers from encouraging cruel behavior or even a simulation of it. The result is a dearth of fresh data to explain how sadistic behavior can become habitual for other- wise good people, as the multitude of theories in psychology and elsewhere can attest.

James Waller, social psychologist at Whitman College and author of "Becoming Evil: How Ordinary People Commit Genocide and Mass Killing," says soldiers called upon to humiliate the enemy must either learn to relish the task or run the risk of being paralyzed by guilt.

"The [victim] dehumanization process occurs because the perpetrator needs it to commit these atrocities," Mr. Waller says. "It becomes easier for them to do what they do if they buy into the justification that this person fully deserves what they're getting. In fact, in this alternative moral universe, it would be an act of injustice not to belittle and abuse them."

Getting to that point, Waller says, depends on accepting rhetoric that equates the enemy with vermin - in this case, perceiving them as terrorists who measure up as sub-human and worthy of annihilation. Yet even with such ample rhetoric in mind, he says, a person may hesitate until he or she completes a first act of brutality, which "opens a floodgate" of base human behavior.

Crossing that threshold, which can seem unthinkable from an outside perspective, tends to occur when an individual feels bound to a group and compelled to adhere to group standards, Dr. Miller says. He cites a 1960s study in which Yale psychologist Stanley Milgram showed that ordinary people, when instructed by an authority figure, will administer seemingly deadly shock "therapies" to a stranger. Another study by Philip Zimbardo at Stanford University in 1971 ended abruptly because subjects, simulating prison guards, "became sadistic."

Still, the mystery lingers: Why the enjoyment in watching others suffer? Perhaps glee merely covers up fear or shame beneath the pressures of war. But theologians quickly cast the indictment wider. Some see humankind perpetually struggling with a dark desire to wish enemies humiliated and to laugh when they are.

Even a professor of moral theology knows the sadistic impulse from personal experience. Thomas Massaro of Weston Jesuit School of Theology recalls driving in the Bronx years ago when another driver cut him off. Further up the road, he saw the same driver had crashed into a pole. His first reaction was gleeful: "At least for a minute, I said, 'Ha! I hope he has expensive damage to his car!' "

Professor Massaro soon repented for wishing another ill, but not before gaining a new insight: The thirst for revenge includes a longing to laugh at the wrongdoer's misfortune.

"These are inmates suspected of having shot at US soldiers," Massaro says. "These [guards] at Abu Ghraib could have had friends killed by these enemies." To resist the desire to degrade and dehumanize is the moral imperative, he says, but doing so in certain settings requires an uncommonly steely will.

Some personalities, too, might be more prone to sadism than others, psychologists suggest. To reduce the likelihood of sadism among its prison guards, Maryland uses a personality inventory to screen out those with "a tendency to do bad things and nasty things," says William Sondervan, former Maryland commissioner of corrections and now director of professional development for the American Correctional Association.

Even after a screening, however, tensions can lead to temptations. In Maryland's rural prisons, 77 percent of inmates are African-Americans from urban areas, while 99 percent of guards are whites from the local vicinity. When an HIV-positive inmate splashes a guard with his urine, blood, or feces, Mr. Sondervan says, guards can be tempted to take pleasure in striking back. But those who can't control that impulse are reprimanded or fired.

"People who do those things tend to get weeded out," Sondervan says.

In military settings such as Abu Ghraib, however, staffing shortages can preclude the luxury of personality screening - and sadistic behavior can result. People who have a high opinion of themselves but feel easily threatened are quickest to become enraged and to delight in seeing the offender suffer, Miller says. "Then you have the mix that can really be devastating."

Whether personality is a major factor in manifesting sadism among ordinary people is a matter of debate. Waller, for one, questions whether personality should even be considered as a factor.

Not everyone, sources agree, will succumb even to the strongest pressures to behave sadistically. Army soldier Joseph Darby, who reported the abuse at Abu Ghraib to his commander, chose to resist even though it meant he might be labeled a traitor. Yet in the aftermath of Sept. 11, it seems an angry America in search of security may have lessened the vigilance against cruelty.

"After 9/11, there came a mentality that said, 'We cannot afford to be nice. We have to do whatever it takes to find these people and bring down Osama bin Laden,' " Morrow says. "It seems to me that this is the atmosphere where these things may occur."