# 49. Manipulation of bias and heuristics in decision making ## 49.5. Methodology/Refinements/Sub-species ### 49.5.55. Reactance This is the urge to do the opposite of what someone wants you to do, out of a need to resist a perceived attempt to constrain your freedom of choice (also known as "Reverse psychology"). A manipulator can use this tendency to persuade a victim to act in a certain way, simply by encouraging them to do the contrary. The victim, in a reactive attempt to show that they are "free", ends up being manipulated.