Leon has procrastinated, and is cramming in an attempt to memorize a great deal of material for his final exams. Finished at last, he goes to bed. Unfortunately, his next-door neighbor has a noisy, barking dog. The barking interrupts Leon's sleep cycle, especially during REM sleep. The next day Leon does very poorly on his exams. According to the information-processing theory of dreams, one explanation for his poor performance (in addition to his study habits) is that: