The old adage is true: Your eyes really are the windows to your soul.Eye contact is the most communicative non-verbal cue we have—so much that it sometimes conveys more about our thoughts and feelings than our words. Ever stare lovingly into your sweetheart’s eyes? Or noticed a baby ogling you on the city bus?

Lucky you—many studies show that people gaze longer at people they like or find attractive.It’s a contagious effect too. Babies will look at a face three times as long if that person is returning the favor; reciprocal gaze implies mutual adoration, which we love as social beings.

Similarly, when it comes to the ol’ game of love, our eyes are clever little messengers: Our pupils dilate when we’re looking at someone we’re attracted to, so fittingly, both males and females rate large pupils as an attractive quality. It signals someone who adores you!

VIDEO: The Anatomy of VisionThe shape of your eyes tells a biological story as well. Large eyes in a female suggest that she has low androgen (male) hormones and high estrogen, which implies youth and fertility. Luckily, it’s also an effect that can easily be faked or enhanced with clever makeup tricks.

As for eye color? As fascinating as the kaleidoscope of colors can be, scientists think it merely reflects the arbitrary mating preferences of our ancestors. But they’re all gorgeous nonetheless and, trust us, there’s a reason to love every unique hue!