A new study suggests we didn’t evolve to find healthy people more attractive.
By Nathan Collins
(Photo: Mattel/Newsmakers)
It’s plausible, thinking back on our species’ history, that there was an advantage to finding a healthy mate. Therefore, it’s also plausible that we would have evolved to find healthier prospects more attractive.
Plausible, but probably not true: According to a new study, there’s no correlation between sex appeal and certain measures of a person’s health.
“Our preferences for attractive individuals are said to represent evolved adaptations for finding high-quality, healthy mates. If this is true, then we expect health to predict mating success in humans,” Yong Zhi Foo, Leigh W. Simmons, and Gillian Rhodes write in Royal Society Open Science.But that’s not what the researchers found.
“Our results provide little support for claims that health, at least the health measures we used, increases mating success in relatively healthy humans,” they write.
It’s not that arguments connecting attractiveness and health are without merit. In certain birds, for example, parasites affect males’ plumage and songs, potentially making them less appealing to mates. And there’s some indication that oxidative stress—essentially, how well an animal manages much-needed but ultimately corrosive oxygen in the body—also affects sexual displays.
But how does this play out in humans? To answer that question, Foo, Simmons, and Rhodes recruited 101 men and 80 women between the ages of 18 and 35 from around the University of Western Australia. Each of those people were tested to determine their immune health—specifically, a saliva test to measure antimicrobial function—and oxidative stress, and each took a quick survey on their sexual history. Finally, a separate group of people had a look at photographs of each participant and rated their attractiveness on a scale of one to nine.
Perhaps unsurprisingly, men who were rated as more attractive had had more sexual partners on average and lost their virginity at a younger age, although there was no such correlation for women.
Yet there was no connection between immune function and oxidative stress, on the one hand, and attractiveness and sexual history, on the other—a result that held for both women and men.
The study is not likely to settle any debates, of course. As the researchers point out, they focus on only a few indicators of health, and none that are particularly good indicators of long-term health. (Indeed, some of the same researchers found in 2010 that markers of long-term immune adaptability may be associated with the number of women’s sexual partners.) The study participants also had good food, shelter, and modern medicine, and it’s possible, the authors write, that immune health and oxidative stress would have a bigger impact in other populations.
“To further understand the relationship, future research will need to investigate other measures of health and to study populations that vary more in health,” they write.
