Brainwashing is a process in which someone is convinced to abandon previously held beliefs and take up new values and ideals. There is a great deal of misconception about this practice, ranging from paranoid delusions about government mind control devices which can supposedly be used like remote controls to skeptics who firmly avow that any form of brainwashing is impossible. The truth, as it often does, lies somewhere in the middle.
In the process of brainwashing, someone is persuaded to believe something through a combination of tactics. There are many approaches to this, but they all tend to rely on separating someone from everything he or she knows, breaking that person down to a vulnerable emotional state, and then gradually introducing new concepts. As people absorb the new material, they are rewarded for expressing thoughts and ideas which conform with these ideas, further reinforcing the brainwashing.
People have been using brainwashing techniques on each other for a very long time. Historically, for example, prisoners of wars were sometimes broken down and persuaded to switch sides, occasionally becoming fervent converts to new ideas. In the 20th century, the term “brainwashing” arose, as did more sophisticated techniques which could be used to forcibly indoctrinate people. These techniques relied on the field of psychology, which demonstrated how people could be persuaded to change their minds.
Some governments have been accused of controlling the minds of their citizens to force them to accept and support a particular point of view, or of brainwashing prisoners of war. Such charges have also been leveled against kidnappers, and many cults are accused of utilizing mind control tactics to keep their members compliant. Whether it's referred to as re-education, thought reform, forced indoctrination, or brainwashing, the technique can be quite insidious when it is performed by an expert.
On occasion, people have used a mind control defense to excuse behavior which would normally be considered unacceptable. A hostage who turns into a criminal, for example, might suggest that he or she was brainwashed by the captors, and that the hostage is therefore not responsible for criminal activity.
More commonly, people are simply persuaded to a point of view, rather than being brainwashed. True brainwashing, in which someone's former value system is deconstructed and replaced, is actually quite rare. Instead, people are persuaded to come around to another point of view, sometimes with the use of forcible tactics, and sometimes not. In both cases, it can take some serious work to deprogram the results of the brainwashing or determined persuasion.