Answer: Sleep
Explanation:
According to psychology field, memory functions as per collecting information, storing it in mind and then recalling it at the time of requirement afterwards.Memory faces problem in recalling information if any disruption, distraction, storage issue is created.
According to the question,Roberto decided to sleep instead of joining his friends for night study session as mind requires relaxation and break from continuous processing otherwise it might lead to retrieval or storage problem of information.Thus, he wants efficient memory function for recalling information during test.
