|Tell me about your mother|
|Let us examine...|
“”Give me the child until he is seven, and I will give you the man.
|—St. Francis Xavier|
Brainwashing is a colloquial term used to describe any process that either undermines a person's perceived "free will", or forces them to undergo a substantial personality shift. The term seems to originate from the Korean War, when many American GIs claimed that the Chinese attempted to force them to renounce America and capitalism. This led to scare movies like The Manchurian Candidate.
Of course, one person's brainwashing is another person's therapy. Is behavioral psychiatry brainwashing? Does it matter if the person signs up for it voluntarily? And, if these are the criteria, how is it different from what a cult does? It is unknown to what degree a person can actually be "brainwashed". For ethical reasons it is impossible to set up an experiment and test the process. Although it is apparently ethical for stage hypnotists to make people do wild things in the name of entertainment, professionals who are open about the subject (such as Derren Brown) admit that it is mostly people just acting up on stage for the attention. Whether this could also apply to non-staged brainwashing isn't known.
The theory of brainwashing may serve as a justification for "deprogramming," or attempts to force a person to give up allegiance to some religious group, usually a cult; this is often involuntary and may involve illegal practices such as kidnapping. Deprogramming took place during the American cult wars in the 1970s and 1980s, but has become rare.
Clearly, if conversion and adherence to a cult can be explained with more common, down to earth concepts, like socialization, social influence, propaganda then the brainwashing theory should be rejected.