Final answer:
Regression is the ego defense mechanism in which a person who is confronted with anxiety returns to a more immature behavioral stage. This maladaptive response involves reverting back to earlier stages of development to cope with stressors.
Step-by-step explanation:
The ego defense mechanism in which a person who is confronted with anxiety returns to a more immature behavioral stage is called regression. This defense mechanism involves reverting back to earlier stages of development in order to cope with stressors. For example, a person may act much younger than their age when faced with a stressful situation.
Regression is considered maladaptive since it involves using less emotionally mature behaviors and thought processes instead of more effective problem-solving and coping strategies. It may provide temporary relief, but in the long term, it can hinder personal growth and hinder one's ability to effectively deal with stress.