 The reason the peacock looks like this and the peahen looks like this is because of sexual selection. The females prefer males with the most elaborate displays. How does this make sense evolutionarily? How can appearance offer insight into the health of a potential mate? Having such ornate excessive plumage is risky. The poor peacock can barely get off the ground, and this is hardly effective camouflage against predators. And so the fact that the peacock could survive despite such costly ornamentation offers a sense of how robust the bird's genetics must be. So natural selection might favor females attracted to that sort of thing. So are you just born attractive or not? Well, some species use diet to increase their sexual attractiveness. Great tits prefer carotenoid-rich caterpillars which play a role in plumage pigmentation. Their breasts become brighter yellow, which is more attractive to potential mates, and a signal of how good they may be at procuring food and as a reflection of their health status since yellow carotenoids like lutein are so health-promoting. So scientists wondered if the same phenomenon could be found in the human species. Published in the International Journal of Primatology, facial skin coloration affects perceived health of human faces. The face plays a significant role in human interactions, including mate choice. So the researchers took digital photographs of Caucasian men and women and allowed people to turn a dial to manipulate various color values until they came up with what they perceived to be the healthiest-looking color, and both men and women preferred increased yellow, the proverbial golden glow. In other words, greens to be gorgeous. We suggest that the healthy appearance of skin yellowness may be attributable to dietary carotenoid deposition in the skin. This suggests that carotenoids, which are involved in health signaling and sexual selection in many species of birds and fish, may also affect the appearance of health in humans. In fact, it's a popular view that sun tanning enhances the healthy and attractive appearance of Caucasian faces, but this research suggests that any benefit to health appearance from tanning is due to the associated increase in skin yellowness. And then if you separate it out, people actually prefer the lighter, more yellow skin, so better than a tanning bed to improve our healthfulness and attractiveness is a bed of greens.