Also mentioned by Ezekiel :

Starting in 1950, the US CIA funded several decades of academic research into the relative usefulness of drugs, electroshock, violence, and other coercive techniques to discover a new method of psychological torture - perhaps the most significant revolution in this cruel science during the past four centuries. Instead of a simple physical brutality, these units practiced a distinctive form of psychological torture with wider implications for the military and its society.

The CIA's thousand-page torture manual, distributed to military regimes in Latin America for over 20 years, taught psychological tactics to break down what the Agency called a victim's capacity to resist. Through persistent manipulation of time, the interrogator can break a victim's will, driving the victim, in the CIA's words, deeper and deeper into himself, until he is no longer able to control his responses in an adult fashion.