Psychology Professor Richard Russell said that the contrast between the features and the surrounding skin reduces as we catch up with age. It is often easy to spot older faces as they have less contrast as compared to younger ones.
During a study, Russell discovered that the ageing process also changes the color of the lips, eyes and eyebrows. The skin just happens to get darker. This causes reduced contrast between the features and the surrounding skin, giving an appearance of older faces.
During another study scientists used artificial ways to enhance facial contrasts and found people said these faces were younger. When the contrasts were reduced, the faces were thought to be older.
It is perhaps for this reason that the cosmetic industry uses contrasting colors to enhance beauty which makes the person appear younger.