 Deirdre Barrett, the dream researcher at Harvard, says dreams can serve all of these functions and more. I think it's kind of like asking what the function of waking thought is. Meaning, our waking thoughts don't just serve one purpose, and our sleeping thoughts don't either. So, takeaway one, dreams have a lot of applications. Think about how you want to use them. Do you want to understand your emotions? To figure out what's really bothering you? To prepare for an upcoming test or performance or event?