A new study that gave its subjects a mild taste of such interrogation methods as solitary confinement, sleep deprivation and extreme cold found most respondents characterized what they felt as torture.

Those who did not experience these techniques but were told about them generally underestimated how much pain they might cause, the researchers found.

"Because policymakers do not subject themselves to interrogation before assessing its permissibility, those who evaluate interrogation policies must predominantly rely on their subjective intuitions about how painful the experience seems," the authors wrote.

Torture is banned in most countries, but the study said the United Nations Convention Against Torture offers a definition of torture that is open to interpretation: "infliction of severe physical or mental pain or suffering."

"What this paper shows is that the legal standard of pain severity proves to be psychologically untenable," said study co-author Loran Nordgren of Northwestern University's Kellogg School of Management.

PAIN'S TRANSFORMATIVE POWER

"People who aren't actively experiencing pain don't understand how transformative it is," Nordgren stated.

This so-called "empathy gap" — the underestimation of pain by those who don't feel it themselves — was seen in officials who consistently underestimated the pain caused by such Bush-era interrogation techniques as water-boarding, isolation and extreme cold.

In the experiment conducted at Northwestern's campus in Illionis, test subjects faced challenges meant to give a small taste of full-scale interrogation techniques.

Instead of solitary confinement, subjects were excluded from an online ball-toss game. Sleep deprivation was simulated by a three-hour night class. To approximate confinement in a cold cell, some participants had one arm in a bucket of ice-cold water.

Some participants merely heard about the interrogation techniques but did not experience the mild forms themselves.

Afterwards, participants rated how severe the pain was and how ethical the actual interrogation techniques were. Those who endured the mild pain rated the technique more severe and less ethical. Those who didn't, didn't.

If those who had felt the pain of these mild procedures were questioned about them 10 minutes after the pain stopped, they also failed to rate the technique as severely painful.

To correct for this tendency to underestimate pain that others suffer, Nordgren suggested overcompensation.

"Knowing that we tend to be biased toward not counting torture as torture, we should define torture very liberally, very inclusively," he pointed out. "This is an area where we can't rely on our emotional system to guide us. We have to use our intellect."