As people age, the color of their lips, eyes and eyebrows gets lighter, while the skin of their faces darkens, creating an overall low-contrast effect. A team of psychologists wanted to prove the flipside, that more contrast is a signal of youth. They asked participants to look at photos of nearly 300 faces and estimate their ages. When the scientists artificially decreased the photos’ contrast, the participants rated faces as older, while when contrast was increased, the participants thought the faces were younger. Now we know that colorful lipstick and dark, smoky eyes can boost the wow factor and the youth factor.