Answer:
spontaneous recovery
Explanation:
Spontaneous recovery is a phenomenon that involves suddenly displaying a behavior that was thought to be extinct.
Spontaneous recovery can be defined as the reappearance of the conditioned response after a rest period or period of lessened response
After a conditioned response has been extinguished, spontaneous recovery may gradually increase as time passes. However, the returned response will generally not be the same strength as the original response unless additional conditioned takes place.
For example, In this context , Peter fear of cats became lessened due to the fact has a black kitten which his parents gave him, but upon sighting a black cat running towards him he developed that old fear which was gradually reducing.This can be described as a spontaneous recovery