The age old myth that you can see the passion in your lover’s eyes is not just another piece of scientific lore. It has actually been proven for more than two centuries that the pupils of a person’s eyes can reveal their true feelings, with one of those particularly being love.

Studies dating back to the 19th century have attempted to uncover the truth behind the connection between emotions and the human eye. Though many details still remain to be discovered, there have been enough studies and collected proof in the scientific community to verify that the pupil of the eye does, in fact, display the purest forms of emotions such as love and desire with the expansion and contraction of the iris.

An eye’s pupil is controlled by the brain’s autonomic nervous system through the sphincter and dilator muscles, which direct how the pupil contracts and expands. The pupils reaction to the stimulants given out by the nervous system can therefore display the most intimate emotions a person may be feeling toward somebody.

“Studies have shown that our pupils dilate wider than normal when we are excited about something and even someone,” Cheryl Murphy states in her article regarding the relationship between eyes and love in Scientific American.

The best explanation for this dilation is the autonomic nervous system’s control of anatomical features when it processes the excitement of a sexual attraction, thus resulting in a creation of reactants. One of these main reactions is a dramatic increase in heart rate. This division of the nervous system sends signals to the heart as it processes the excitement that comes with desire, excelling the overall heart rate. Not only is the system controlling the muscles of the heart, but also the muscles that control the pupil, making them dilate in response. So therefore, by looking into a lover’s eyes or even feeling their pulse, one can actually witness the love and attraction displayed in their partner’s eyes.

“When the pupil dilates, it takes in more information so it kind of makes sense that if you’re interested, or in love, or emotionally connected to someone, there’s a biological response and physiological reaction,” AP Psychology teacher Mr. David Peters said. So the next time you’re on a date, it may not be a bad idea to study the eyes of your partner to see if his or her interest is only a facade or the beginning of a legitimate attraction and new love.