You sweep mascara on every morning, apply lipstick pre-meeting, use eyeliner on your way to a fancy dinner date—clearly, makeup matters. But why it matters is perhaps more scientific than you realized. Amazingly, it’s all about creating contrast. The darker your facial features are in relation to your skintone, the more feminine your face appears.

Research proves that this phenomenon is so important, in fact, that the exact same face can be perceived as male or feminine depending on the level of contrast. Imagine that! And when you digitally darken the eyes and lips on a woman’s face? You guessed it, people rate it as being more attractive. It’s not all about inky mascara and eyeliners though—foundation and coverup can also make a woman appear more attractive by evening out her skintone. Healthy skin implies that she’s young and healthy—and fertile.

MORE: The Science of Makeup