Habituation

Habituation is the neurobiological process by which the response to a stimulus decreases with repeated exposure to that same stimulus. It is the mechanism that explains why gradual exposure works in treating phobias and anxiety: by staying in contact with the feared stimulus instead of avoiding it, the anxious response naturally decreases.

Habituation was once believed to be the main mechanism behind exposure therapy. More recent research indicates the core mechanism is actually active inhibition — the brain learns a new association ('X is safe') that inhibits the fear response, without erasing the original fear. That's why exposure needs to be practiced repeatedly across different contexts — the learned inhibition is context-specific.

Practical implication: fear can 'return' in new contexts even after successful exposure in a specific one — this isn't a treatment failure, but a sign that the exposure needs to be generalized further.