Narrator: This is Science Today. Social relationships and networks have been shown to improve both health and longevity. According to Malcolm Zaretsky, a molecular and cell biologist at the University of California, Berkeley, when it comes to identical twins, their genetic similarities makes a close relationship even more beneficial.
Zaretsky: Now perhaps there is something happens to identical twins when they are very young because they are so similar that they modify each other's brains in such a way that it does not happen with fraternal twins.
Narrator: Zaretsky says that the close and frequent communication among identical twins can provide a beneficial influence on their behavior and in turn, increase their life spans.
Zaretsky: When you are always in close contact with an individual who is very much like you, the other person's behavior probably affects you to a much greater extent than if you weren't identical twins. And this could be sort of a basis of competition and cooperation for a better lifestyle, which continues into older age.
Narrator: For Science Today, I'm Larissa Branin.