One of my all-time favorite songs, for which my girlfriend always calls me a redneck, is Mickey Gilley’s "Don't the Girls All Get Prettier at Closing Time." As the title suggests, it’s about the fact that a little booze makes everyone a little easier on the eyes. Does science have an explanation for “beer goggles,” or is it magic—and proof that alcohol is here because some higher power is looking after us?

A study published last year in the journal Alcohol suggests that it may have something to do with symmetry (prior to that, an eyecare industry-funded study had worked out an elaborate formula that accounted for several factors present in the average pub). Almost all organisms with more than one cell exhibit some sort of symmetry, whether it's radial, biradial, spherical or bilateral (notable exceptions: sea sponges and adult flatfish, like flounder). You could cut me, or a dog, or an apple or a dinosaur in half, and one side would be pretty much a mirror image of the other. Some organisms have more lines of symmetry than others, and some individuals are more symmetrical than others.

Now, symmetry probably isn’t something you’re really thinking about when cruising for eligible members of your preferred gender in a bar, but you may be looking for it subconsciously. Humans tend to judge symmetrical faces as more attractive than asymmetrical ones and may have a strong evolutionary preference for it, since symmetry might be a signal of good health and good genes.

In the Alcohol study, researchers from London's Roehampton University went to a few bars near campus and found both inebriated and sober students. They showed all of them 20 images of a pair of faces and 20 images of a single face, and asked which faces in the pairs were the more attractive of the two, and whether or not the solo faces were symmetrical.

The sober kids overwhelmingly said the more symmetrical faces in the pairs were more attractive. They were better able to determine which of the solo faces were more symmetrical, too. The drunk students, on the other hand, had less of a preference for symmetry and a deadened ability for detecting it (and women more so than men).

The researchers concluded that a “reduced ability to perceive asymmetry” could underlie “increased frequency of mate choice.” In layman’s terms, what the study suggests is that alcohol doesn’t necessarily make everyone more beautiful. It’s just that beer goggles degrade our ability to recognize asymmetry when we see it.

L.G. Halsey, J.W. Huber, R.D.J. Bufton, A.C. Little. “An explanation for enhanced perceptions of attractiveness after alcohol consumption.” Alcohol. Volume 44, Issue 4, June 2010.