You were going to study, but then your mother said, "Study now!" Suddenly, you didn't want to. Why? People want to choose things for themselves.

When someone gives orders or says "Don't!", we often want to do the opposite. This is called psychological reactance. In one study, a warning label on violent TV shows made some people want to watch them more.

Psychological reactance is the urge to push back when we feel our freedom is being taken away. The idea was proposed in 1966 by the American psychologist Jack Brehm. When people are ordered or forbidden to do something, they may find the forbidden option more attractive or feel annoyed with the person giving orders.

In a 1996 study, warning labels saying that a TV show contained violence actually made some viewers more interested in watching it. In Japan, this is sometimes called the "Caligula effect." However, not every popular example is supported. The "Romeo and Juliet effect", the idea that love grows stronger when parents disagree, was not confirmed in a 2014 study.

Psychological reactance, a theory proposed by Jack Brehm in 1966, holds that when people perceive a threat to their freedom of choice, they become motivated to restore it. This can make a forbidden option seem more appealing, prompt people to do the opposite of what they are told, or provoke irritation toward the source of pressure. A 1996 study illustrated the "forbidden fruit" effect: warning labels stating that a television program contained violence increased some participants' desire to watch it, especially when the label came from an authoritative source and among people with a strong tendency toward reactance, whereas information labels had a weaker effect.

In Japan, the phenomenon is sometimes called the "Caligula effect", a popular label rather than a formal technical term. A 2013 meta-analysis supported the view that reactance is best understood as an intertwined mix of anger and counterarguments, and research on health campaigns suggests that forceful phrases such as "you must" can undermine persuasion. Not every popular claim survives scrutiny, however. A 2014 reexamination of the "Romeo and Juliet effect" found that disapproval from family and friends was linked to lower relationship satisfaction instead of stronger love.