Narrator: Your personality affects the way you dream, but in a way you might not expect. This is Science Today. Virginia Tonay, a psychologist at the University of California, Santa Cruz, studies the way people dream -- and what they dream.

Tonay: I've noticed that in studying emotions in dreams and in waking life that people who are very emotional in their waking life tend to have fewer emotions in their dreams. And people who tend to be more thinking kinds of people, very intellectual, valuing rationality, tend to have more emotions.

Narrator: In other words, your dreams tend to balance your emotions. That's especially true if you're going through a difficult time when you're apprehensive or upset.

Tonay: Following the earthquake here for example, this was the case. People would have very happy dreams. Not what you would expect. So it seems that dreams have a function that's emotional that has to do with balancing feelings, I think. If we get toward one extreme or the other, I think that dreaming is one way that we can sort of bring that back into balance from the extreme back more towards the middle.

Narrator: For Science Today, I'm Steve Tokar.