Answer:
Social impairment
Explanation:
Social impairment: In psychology, the term "social impairment" is described as a phenomenon that occurs when a person performs worse or behaves in a less "positive way" when he or she is surrounded with other persons. While performing a specific task an individual would perform it better when he or she is alone instead of being in a crowd and there is often a chance of making mistakes as the person might feel anxious.
In the question above, John is a victim of social impairment.