phobias

Meaning: A phobia is an anxiety disorder marked by intense, persistent fear of a specific object or situation, out of proportion to the real danger, leading to avoidance or marked distress. The MCAT groups phobias as specific phobia (animals, heights), social anxiety disorder (social phobia), and agoraphobia (fear of situations where escape seems difficult). In the learning account, a neutral stimulus paired with an aversive event becomes a conditioned stimulus that triggers fear, as in Watson's Little Albert study. Avoiding the stimulus relieves anxiety, which is negative reinforcement, so the avoidance persists. A biological account adds preparedness: humans may acquire some fears, such as of snakes or heights, more readily than others.

On the MCAT: A passage describes someone afraid of elevators or dogs. You identify acquisition as classical conditioning, maintenance as negative reinforcement, and treatment as systematic desensitization (relaxation paired with a graded fear hierarchy, a form of counterconditioning) or exposure therapy, including flooding. Extinction requires contact with the feared stimulus without the aversive outcome, which avoidance prevents.

Common confusion: Avoidance is negative reinforcement, not punishment or positive reinforcement, because removing anxiety strengthens the behavior. Also, a phobia has a specific trigger, unlike generalized anxiety disorder (diffuse worry) or panic disorder (attacks that can come unexpectedly).