Researchers claim they can spot the signs of romance in people starting a new relationship by looking at how much their brains light up when thinking about the object of their affection.
The scientists detected distinctive patterns of electrical activity in the brains of volunteers who believed they had recently fallen in love.
They claim that scans can predict whether the couple stayed together - or not.
Even if someone believes they are truly, madly, deeply in love, neuron activity can suggest whether their feelings were strong enough for them to be with their current partner three years later.
"All of those involved in the study felt very intensely in love with their partner and this was reflected in their scans, but there were some subtle indicators that showed how stable those feelings were," Professor Arthur Aron, a social psychologist at Stony Brook University, New York told the Sunday Telegraph.
Research published in the journal Neuroscience Letters, found a number of key sections of the brain were involved.
Using magnetic resonance imaging, the scientists scanned 12 volunteers, seven of whom were women, who had fallen deeply in love and had been with their partners for over 12 months.
As they were scanned, each was show a picture of their love object and asked to think of memories of them.
The respondents were also asked to think and look at a picture of an acquaintance that they had no feelings of romance for.
Three years later, the scientists compared the scans with the outcome of each relationship. Around half of the relationships had lasted.
The researchers found that the scans of those still in relationships had heightened levels of activity, when thinking about their partners.
The brain area, known as the caudate tail, produces emotional responses to visual beauty, showed heightened activity.
Aron said the research could have a practical application in helping people with relationship problems.
"We may eventually get to a point where we can recognise things that the person doesn't recognise themselves and we can say that they are not as intensely attached to a person as they think they are."
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