On the other hand, Fisher's theory also holds hope for those who look back wistfully, wishing they could recreate those heady days of early romance. Fisher suspects that parenting, in particular, may suppress the dopamine spark in relationships. But not necessarily forever. Later in the relationship the chemistry may return; long-time partners may somehow "fall" in love all over again, and be carried away on a dopamine high.
And people who have lost one partner thus may tumble again for another. Among those couples that Fisher is studying are newly met partners in nursing homes, people in their 70s and 80s, whose infatuation is just as intense as that shared by 20-year-old lovers. "I think there's a wonderful message in that," she says.
ILLUSTRATIONS
BY DEBORAH BLUM
Deborah Blum is a Pulitzer Prize-winning science writer, the author of Sex and the Brain (Viking), and a professor in the School of Journalism at the University of Wisconsin.
