When someone looks at you, it can be difficult to tell whether their attraction to you is based on love or lust. But now these intentions can be identified through body language, and more specifically by studying the person’s gaze. In the first case, the person will focus on the face, whereas in the second, they will focus on the body. This all takes place in less than half a second, so you’ll need to pay close attention!

To uncover the difference between these two types of desire, researchers from the universities of Chicago and Geneva studied the eye patterns of students during two experiments. The volunteers were first presented with a series of photos each showing a young couple looking at each other. In the second part of the experiment, the photos showed members of the opposite sex looking directly at the camera. Student eye moments were recorded throughout the experiment. In both cases, the students were asked to quickly identify their initial emotional reaction to the individuals in the photos.

By comparing these two sets of data, researchers found that there was a distinct difference between patterns of eye movement in both situations. The students focused on the face of a person when they described romantic attraction, but their gaze was directed toward the body when they described sexual attraction. Contrary to what one might think, these results were observed in both men and women alike. Finally, there was no difference in reaction time between romantic and sexual attraction, which demonstrates how quickly the brain processes both emotions.

"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," concludes co-author John Cacioppo, while adding that the data could also be used in the field of couple therapy.