Are they really in love, or is it just lust? Researchers believe they can accurately tell the difference based on eye patterns alone, raising the question "can there be love at first sight?"
Lead author Stephanie Cacioppo, director of the High-Performance Electrical NeuroImaging Laboratory at the University of Chicago, attempts to answer these questions in a study recently published in the journal Psychological Science.
"Although little is currently known about the science of love at first sight or how people fall in love, these patterns of response provide the first clues regarding how automatic attentional processes, such as eye gaze, may differentiate feelings of love from feelings of desire toward strangers," she said in a statement.
For the study, Cacioppo and fellow researchers from the University of Geneva in Switzerland had university students view a series of black-and-white photographs of strangers.
In one part, male and female participants were asked to look at photos of young heterosexual couples who were gazing at one another. The participants were asked to say whether the photo made them think of lust or love.
In a second part, the participants looked at photos of the opposite sex looking at the camera. For each photo, they were asked whether or not they felt sexual desire or more romantic urges. It is important to note that the participants identified as heterosexual and all decisions were asked to be split-second without time for consideration.
During both these parts of the study, the eyes of the students were tracked as they made their decisions.
The researchers quickly found a predictable trend. Photos of couples staring into one another's eyes were more commonly associated with "love" while couples ogling one another's bodies were clearly "lustful," to the participants.
Interestingly, this held true for their own interactions as well. Participants whose eyes tracked the body more than the face of a participant usually said "lust" for the photo, while attention to the face warranted more "love" responses.
As obvious as this may seem, co-author John Cacioppo explained that having scientific evidence of this phenomenon is an important step towards better understanding love.
"By identifying eye patterns that are specific to love-related stimuli, the study may contribute to the development of a biomarker that differentiates feelings of romantic love versus sexual desire," he said.
The study was published in Psychological Science on July 16.