Answer:
Length of delay between learning and relearning
Explanation:
Herman Ebbinghaus was one of the first psychologists to study the memory. He is responsible for the creation of the Forgetting Curve, among other concepts that shaped our understanding of human memory. According to him, people's learning was conditioned to the length of delay between learning and relearning, which means that the more time you spent not learning about something, the more time you'll to undertake to relearn it.
