问答题 Dreaming is a "mood regulatory system," says Rosalind Cartwright, PhD, chairman of the psychology department at Rush University Medical Center in Chicago. She's found that dreams help people work through the day's emotional quandaries. "It's like having a built-in therapist," says Cartwright. While we sleep, dreams compare new emotional experience to old memories, creating plaid-like patterns of old images laid on top of new ones. As she puts it, "You may wake up and think, what was Uncle Harry doing in my dream? I haven't seen him for 50 years. But the old and new images are emotionally related." It's the job of the conscious mind to figure out the relationship.