Defense mechanisms refer to processes of self-deception that protect people from anxious thoughts or feelings.
The concept arose from Sigmund Freud’s theory of personality. According to Freud’s famous model, the mind has three dueling forces: the id (unconscious and primitive urges for food, comfort, and sex), the superego (a partly conscious drive toward moral and social values), and the ego (a partly conscious force that moderates the id and superego).
Anxiety emerges when the needs of the id clash with the needs of the superego. To mitigate the tension, the ego deploys strategies of self-deception to avoid the discomfort. The unacceptable thought or emotion may be denied, for example, or rationalized or projected onto someone else.
Defense mechanisms aren’t inherently bad—they can allow people to navigate painful experiences or channel their energy more productively. They become problematic, however, when defense mechanisms are applied too frequently or for too long.
Freud’s framework has proven nearly impossible to empirically validate, and his methods are no longer widely used in therapy. Still, his theories spurred the growth of psychology, and some of his ideas—like defense mechanisms—still stand today.