A typical description of the ideal female beauty always goes “blonde hair, blue eyes.” After Marlowe proposed a solution for the mystery of why men prefer women with large breasts, the attraction of blue eyes remained the only mystery to solve in the area of traits associated with physical attractiveness. We now knew why men preferred women with all the traits that characterize Barbie or a typical blonde bombshell, and we knew the evolutionary logic behind each of them. But eye color, even more so than hair color, seems such an arbitrary trait. Why should women with blue eyes be any different from those with green or brown eyes? Yet a preference for blue eyes seems both universal and undeniable.
There is an additional layer to the mystery of blue eyes. Unlike all the other traits discussed previously in this series of posts (youth, long hair, small waist, large breasts, and blonde hair), which are considered to be attractive only for women, blue eyes are thought to be attractive for both women and men. For instance, a typical description of an attractive man is “tall, dark, and handsome,” not blond; unlike blonde women, blond men are not universally considered to be attractive (because women generally prefer to mate with older, not younger, men). Yet, as the examples of Frank Sinatra (“Ol’ Blue Eyes”) and Paul Newman (who once famously quipped he did not want his epitaph to say “Here lies Paul Newman, who died a failure because his eyes turned brown”) show, men with blue eyes are considered to be attractive, just like women with blue eyes. So it appears that the answer to the question “Why are blue eyes attractive?” must involve more than male sexual preference.
The attraction of blue eyes remained an evolutionary mystery until an undergraduate student of mine, Lee Anne Turney, suggested a novel solution in her term paper for a class that she took from me in Spring 2002. As far as I know, hers is the only available explanation for the attraction of blue eyes that anyone has ever proposed, and it has at least surface plausibility. But, of course, it will have to be subjected to rigorous experimental testing before it can become an accepted explanation.
Turney points out that the human pupil dilates when an individual is exposed to something that he or she likes. For instance, the pupils of women and infants (but not men) spontaneously dilate when they see babies. Thus, pupil dilation, which is usually beyond an individual’s conscious volitional control, can be used as an honest indictor of interest and attraction. Most people aren’t even aware that the size of their pupils changes when they see something they like, so it would be difficult to deceive others by consciously manipulating their pupil size. We cannot help but reveal our interest in and attraction to others through the size of our pupils.
Turney then makes two simple observations. First, every human pupil is dark brown, regardless of the color of the iris, which encloses the pupil and determines the color of the eye. Second, blue is the lightest color of human iris. The consequence of these two observations is that the size of the pupil is easiest to determine in blue eyes. If you face people with different eye colors and must determine whether each person likes or is interested in you, with all else equal, it is easiest to read the blue-eyed person’s level of interest or attraction.
Turney’s argument, which I believe might be true, is that blue-eyed people are considered attractive as potential mates because it is easiest to determined whether they are interested in us or not. It is easier to “read the minds” of people with blue eyes than of those with eyes of any other color, at least when it comes to interest or attraction.
One of the advantages of Turney’s solution to the puzzle of blue eyes is that it not only explains why blue eyes are considered to be ideal in mates but also explains why, unlike all the other traits I discuss in this series of posts, blue eyes are considered to be attractive in both sexes. It is just as important for women to read men’s minds as it is for men to read women’s; if anything, given the far greater consequences of making mistakes by being attracted to the “wrong” person, women should have a greater need to decide whether their potential mate’s seeming interest in them is genuine or not. The negative consequences of being fooled by a lying suitor are much greater for women, so blue eyes should be a more important characteristic in men than in women.
Incidentally, I believe that Turney’s logic can also explain why people with dark brown eyes are often considered to be “mysterious.” They are mysterious because their minds -- that is, whether or not they are interested in or attracted to us -- are much more difficult to assess. The color of the dark brown iris is very similar to the (universal) color of the dark brown pupil, and so it is very difficult to gauge the size of the pupil in dark brown eyes. In one study, many people, both men and women, express dislike for extremely dark brown eyes (as they do for red hair).