Beginning in the 1950s, the CIA became very interested in psychological research being
conducted on the effects of sensory deprivation on humans. The research, that suggested
rapid regression in those tested, provided a framework for sections of what would later be
known as the KUBARK manual, the first a series of US-government documents that
provided techniques for interrogating detainees. These methods involved radically
altering a detainee’s sense of time and environment.
Among these techniques, some developed independently of the manuals by interrogators,
were the manipulation of light and sound. In order to weaken the resolve of a detainee
and prolong “capture shock,” complete sensory deprivation followed by blasts of light or
noise, or very loud music, proved effective. So much so that variations and combinations
of these techniques were widely used by the United States as well as both its allies and
enemies in Vietnam, Latin America, Northern Ireland, and the Middle East.
Though the idea of sound as a weapon is at least as old as the account of Joshua’s siege
of Jericho, it was only recently deemed “inhuman and degrading” for the purposes of
interrogation by the European Court of Human Rights in the 1978 case “Ireland v. the
United Kingdom.”