Psychological manipulation is a type of social influence that aims to change the behavior or perception of others through indirect, deceptive, or underhanded tactics. By advancing the interests of the manipulator, often at another's expense, such methods could be considered exploitative and devious.
Social influence is not necessarily negative. For example, people such as friends, family and doctors, can try to persuade to change clearly unhelpful habits and behaviors. Social influence is generally perceived to be harmless when it respects the right of the influenced to accept or reject it, and is not unduly coercive. Depending on the context and motivations, social influence may constitute underhanded manipulation.