Couple of quick chapters from Operation Mind Control By Walter Bowart....

... The CIA uses thought reform, programming, and indoctrination on its own employees. Patrick J. McGarvey, a veteran of fourteen years in U.S. intelligence service, described the cryptocracy's more ordinary indoctrination procedures in his book CIA: The Myth and the Madness. McGarvey said that his indoctrination was carried out in a classroom which was "right out of The Manchurian Candidate. It was a cavernous room not unlike a nineteenth century surgical exhibition pit."

That training, he said, consisted of "an admixture of common sense, insanity, old-time religion, and some of the weirdest lectures you can imagine." The most important result of this early training, as far as the CIA was concerned, McGarvey said, "was the attitudes they managed to inculcate" among the recruits.

"Many among us believed in the intelligence establishment simply because we were part of it. This attitude lingered for years among us, and today, in middle age, most of us still talk about the mind-bending job they did on us during the training period. I am convinced that this manipulation of attitudes has been responsible for keeping silent the many men who have since left the craft of intelligence. Because of my indoctrination, I still get a visceral twinge— and have qualms of conscience about writing this."

McGarvey was referring to behavior modification when he said, "CIA has a wonderful informal system of rewards and punishments for the faithful and unfaithful."
https://exploringrealhistory.blogspot.com/2019/10/part-4operation-mind-controlthe-slaves.html