Washington ? As interrogation techniques go, the recommended opener from a 1963 CIA manual “My little man, you are not of much concern to us” has gone the way of trench coats and truncheons.

Since then, the agency and others who try to pry information from suspects have evolved a battery of sophisticated psychological techniques to wear them down.

Such tricks, within certain bounds that U.S. authorities say do not cross the line of the legal definition of torture “severe pain” might be used by interrogators whose questions have been faced down by captured al-Qaida fighters trained to be silent or to lie.

The CIA has said it would never subject detainees to the company of rats and cockroaches, for example, or even threaten to do so. But agency manuals from the 1960s through the 1980s discuss the value of endless, meandering chats about whatever gives a captive the creepy crawlies.

Other insights from the manuals:

l A panel of interrogators may subject the suspect to a shouted string of nonsensical questions to create a “surreal” environment, in which a “real” question finally provides relief.

l If the suspect is a low-level operative, his interrogators could subject him to hours and days of sophisticated queries he would not know how to answer, wearing away his confidence, then suddenly spring an easy question he would be eager to answer.

l For more sophisticated captives, another method is to wear down confidence by rewarding noncooperation with better conditions and friendliness at first. The confused captive wonders what help he might be inadvertently providing to elicit such favored treatment.

l Simulating newscasts reporting major losses for the enemy could wear down a captive’s morale, inducing a “why not tell all” attitude.

These techniques are not contentious but human rights groups and intelligence operatives diverge on what happens when “hands off” does not work.

The CIA swore off torture after a training manual with a chapter on its “proper use” was leaked in 1984. Subsequent manuals discussed “coercive techniques” aimed at inducing “discomfort” but not pain.

CIA spokesmen would not discuss the manuals.

Some suggestions fall short of physical abuse: Agents are told they might manipulate perceptions of time by fiddling with clocks, serving food at odd times, waking the captive at odd hours, and keeping lights on 24 hours a day.

Human rights groups say techniques aimed at inducing breakdowns are contrary to laws banning cruel and unusual punishment.

“You’re basically not allowed to use anything to overcome the person’s free will,” said Jamie Fellner of Human Rights Watch.

Even dicier are areas described as discomfort but not pain in 1988 Senate testimony by the top CIA operative, recently declassified by the independent National Security Archive.

Dick Stolz described techniques such as forcing a captive to sit on a stool or stand at attention for long periods. He could be denied sleep, or he could be placed in a soundproof room and his environment could be subject to temperature changes.

Agents from other countries who have been granted similar leeway have stood prisoners for hours in front of blasts of cold, kept them outside in desert conditions all day and night, and plied them with coffee, talk and white noise to keep them awake.

Defense Secretary Donald Rumsfeld said agents interrogating the most senior al-Qaida figure in U.S. custody, Abu Zubaydah, intend to draw “every single thing out of him” that might head off terrorist acts, but will not torture him.

No one has accused interrogators of brute force, but some of the thousands of illegal immigrants detained after Sept. 11 say immigration and police officials roughed them up. And troops posed for photos with American Taliban captive John Walker Lindh, who was wearing handcuffs and a blindfold with an obscenity scrawled across it.