Definition
In psychology, manipulation is defined as an action designed to influence or control another person, usually in an underhanded or subtle manner which facilitates one's personal aims. Methods someone may use to manipulate another person may include seduction, suggestion, coerion and blackmail. Manipulation is generally considered a dishonest form of influence as it is used at the expense of others. Humans are inherently capable of manipulative and deceptive behavior, with the main differences being that of specific personality characteristics or disorders.
Deception
Perhaps the most obvious technique available to this end is deceit. Manipulators deceive their victims about reality, their place in that reality, and about themselves. They can brainwash and threaten, contradict any claim a victim makes about herself, punish her for statements they dislike, and possibly even deny her the authority to make claims at all. The most skilled manipulators will have their victim believe anything about reality and herself they want her to, including the fact that they did not manipulate her into thinking so, or that their manipulation was justified since it allowed her to learn the truth. Striking examples of such identification with such imposed self-images can be found among cult members and victims of extreme abuse