Your roommate is taking a self-paced course that requires three papers over the semester. He expected to finish all three papers in the first two weeks but, after quickly finishing the first paper three weeks ago, he has done nothing. This behavior pattern is due to

Answer: The post-reinforcement pause.

Explanation:

The post-reinforcement pause occurs when the delivery of a reinforcer on fixed-ratio and fixed interval schedule of reinforcement. When he considers not to do anything after having so much before him this behavioural type is known as post-reinforcement pause