Fri, 30 Nov 2012 15:38 UTC
To test the theory of homogamy, which states that individuals generally seek a sexual partner that looks like them, researchers compared the facial features of the men surveyed with those of the women that they considered most attractive.
French researchers from the Institut des Sciences de l'Evolution de Montpellier focused on certain facial characteristics like eye and hair color, lip and eyebrow thickness and the presence or absence of chin dimple, according to the study published Nov. 21 in the journal PLOS One.
Researchers said that there have been numerous studies on what physical characteristics make a woman more attractive. However, unlike the previous studies that focus on traits linked to hormone levels and fertility, the latest study focused on characteristics that offer no particular selective advantage such as eye color and lip thickness.
Researchers wanted to test two separate but non-mutually exclusive evolutional theories: homogamy and uncertainty of paternity.
Researchers said that homogamy has been observed in many animal species and states that individuals have a tendency to choose potential partners that resemble them or, in other words, are genetically similar to them.
The uncertainty of paternity is a theory specific to species that provide paternal care to their offspring. Researchers explain that in order to invest resources in a child that is not their own, men tend to prefer recessive features, such as blue eyes or thin lips, in order to be able to recognize his own characteristics in the child.
To test these two theories, researchers first asked about 100 men to choose from photos of feminine faces those that they found most attractive.
Researchers then repeated the experiment on another group of men, but this time the men had to choose from computer-generated faces.
The findings show that men preferred faces that were similar to their own. For example, when presented with four different faces in the second experiment, 37 percent of men chose the face with which they shared the most features.
However, researchers found no evidence to back up the uncertainty hypothesis.
Researchers then analyzed photographs of real couples with at least one child in order to determine whether these preferences actually influence partner choice.
Once again, researchers found that spouses generally shared more facial traits than two randomly selected individuals, suggesting that homogamy really does apply to the real world.
Researchers said while there have not been many studies on the importance of homogamy, the concept raises many important questions like whether there is an advantage to having parents that are genetically relatively similar, and whether the phenomenon occurs in cultures other than ones specific to the western world.