Which defense mechanism is characterized by behavior that opposes one's true feelings?

The defense mechanism characterized by behavior that opposes one's true feelings is reaction formation. This mechanism involves the individual expressing feelings, thoughts, or behaviors that are diametrically opposed to their actual feelings or thoughts. For example, a person who feels hostility towards someone may behave in a friendly and overly nice manner towards them. This behavior serves as a way to conceal their true feelings, often out of guilt or social appropriateness.

In the context of psychological defenses, reaction formation functions as a way to maintain emotional equilibrium by transforming unacceptable impulses into their opposites. This can help individuals cope with anxiety by avoiding confrontation with their true feelings. Understanding this mechanism can shed light on certain behaviors that may appear contradictory but are rooted in a deeper psychological response to internal conflicts.