Using neuroscience to unlock one of the biggest mysteries of life, researchers are finding neural evidence that falling for a mate is essentially a matter of intoxication.

In a recent study, 17 young people who described themselves as being intensely "in love" were put in an fMRI scanner while being shown photographs. When the pictures were of their partners—versus a familiar, neutral person—reward areas of the brain lit up, says Arthur Aron, PhD, a social psychologist at Stony Brook University, who conducted the study with Helen Fisher, PhD, an anthropologist at Rutgers, and Lucy L. Brown, PhD, a neuroscientist at the Albert Einstein College of Medicine. These areas are rich in dopamine, a neurotransmitter linked to desire and highly involved in addiction to alcohol and drugs.

As partners stay together, the "hooked" state dissipates and brain systems associated with attachment increase in activity. Aron is intrigued by a tiny percentage of couples who say they're passionately in love after ten or 20 years. "We just assumed they had checked the wrong box," he admits. "But we've been scanning them, and we're seeing the same thing we saw in the brains of the newly in-love people. We don't know why yet, but from our interviews these people have all sorts of positive factors going for them. They do exciting things, they have decent communication skills, they're not anxious or depressed."

As for whether online dating will be replaced by outfits like "" or "BrainScan Match," who knows. But there could be a day when you meet a guy, have a few dates, then go in for a brain scan to determine if you're "in like" or "in love." Even if the answer is love, Aron says, "we're still not going to be able to predict how a relationship will work out. That comes down to the basics of good mental health, communication, and social support."