Science is proving once and for all that beauty really is in the eye of the beholder. A new study published in Biology Letters suggests that what is deemed “attractive” changes depending on the environment. Results show that the more extreme and harsh an environment, the less likely a man is to seek feminine features in a prospective mate. Although scientists aren’t sure of the exact reason for the differences in preferences, evolution is thought to be the driving factor for this trend.

The study involved 1,972 heterosexual men from 28 countries. The men were presented with photographs of women altered to look more or less feminine. They were then asked to choose which face appealed to them the most, and the results were compared to various demographic and social characteristics of each nation.

Nepalese Men Aren’t Into 'Girly' Faces

Results showed that, overall, men prefer a feminine face to a more masculine one. Just how much they preferred these feminine faces seemed to change based on location. According to Live Science, in environments where health was worse, as measured by average lifespan, maternal and infant mortality, and other factors, men were more likely to prefer a face with masculine features. Men in Nepal were the least likely to be drawn to the typical "girly" face with large eyes, pillow lips, and a soft jaw. Nigerian and Colombian men also more frequently chose more masculine faces. Japanese men were most likely to choose a mate with highly feminine facial features, followed by Australia. American men also preferred femininity.

The Science Bit

“It might pay off for men in hard conditions to develop a preference for women who are not very highly feminine because feminine women are perceived to be less socially dominant,” Urszula Marcinkowska, a study researcher, explained to Live Science. She added that femininity is also perceived to have less potential at acquiring resources. Based on this reasoning, Marcinkowska has hypothesized that men in harsh conditions may have a better chance of fathering children who survived if they mated with a woman who was able to hold on to resources. Live Science explains that in more extreme environments it may be more important that a potential mate survive long enough to bear any children. Masculine features are associated with better survival skills. “It seems like there’s a trade-off going on, where in the harsher environments, men are putting less preference on femininity,” Dan Kruger, an evolutionary psychologist from the University of Michigan, told Live Science.

What makes a face attractive?

Feminine features are caused by estrogen, the hormone responsible for female fertility. Women with higher levels of estrogen are perceived as having more attractive faces, according to The Telegraph. Estrogen prevents the growth of facial bones, reduces the size of the nose and chin, leads to large eyes, and increases thickness of lips and fat deposition in the cheek area, hips, and buttocks. All these features are meant to be a subconscious signal to males that the woman is fertile. Women are essentially advertising their general fertility with their faces. In evolutionary terms, it makes sense for men to favor feminine fertile women; those that did would have more babies.

Source: Marcinkowska U, Kozlov MV, Cai H, et al. Cross-cultural variation in men’s preference for sexual dimorphism in women’s faces. Biology Letters. 2014.