Saturday, February 25, 2006

Handsome men have "good genes"

If you didn't know why we always find handsome men more attractive and want to get it on with them more than unattractive men, a study suggests that you're picking them so that you will make babies with better genes.

More evidence that we are but vehicles of gene propogation?

"Females gain direct or indirect fitness benefits by choosing between males with traits indicating “good genes,” but we usually know very little about the nature of these genes. However, it has been suggested that genetic quality may often be defined as heterozygosity at certain loci."

"Faces of men who are heterozygous at all three loci are judged more attractive by women than faces of men who are homozygous at one or more of these loci. MHC genes code for proteins involved in immune response. Consistent with this function, faces of MHC heterozygotes are also perceived to be healthier. In a separate test, in the absence of any other cues, patches of skin from the cheeks of heterozygotes are judged healthier than skin of homozygotes, and these ratings correlate with attractiveness judgements for the whole face."

"Because levels of MHC similarity can influence mate preferences in animals and humans, we conducted a second experiment with genotyped women raters, finding that preferences for heterozygosity are independent of the degree of MHC similarity between the men and the female raters."

"Our results are the first to directly link facial attractiveness and a measure of genetic quality and suggest a mechanism to help explain common consensus concerning individual attractiveness. In a relatively monogamous species like humans, evolutionary benefits from choosing heterozygous mates could include prolonged parental care and reduced risk of contracting disease for females and their offspring."

Roberts et al (2005), MHC-heterozygosity and human facial attractiveness, Evolution and Human Behavior, v26(3) p213-226. For those with access, the paper is here.

What I was most tickled with was the methodology.
"Digital color photographs of the men's faces were taken under standard lighting conditions using a Nikon Coolpix 775 digital camera and a resolution of 1600×1200 pixels. Men were instructed to look directly at the camera and adopt a neutral expression. Each image was normalised on the interpupillary distance (Penton-Voak et al., 2001) and digitally masked so that only the face was visible, minimising potentially confounding information about hairstyle and clothing (e.g., Roberts et al., 2004). These images were presented to 50 female participants (age 18–49 years, mean=23) in random order, on a liquid crystal display computer screen (on-screen face size approximately 12×18 cm). Women rated the attractiveness of these faces using a seven-point rating scale (high scores=attractive)."

Aiyah very funny laa.

I stumbled upon this surfing science direct for "Female choice and offspring quality", this period being the desperately-writing-draft-report period before prof spidey returns from China.

My amusement at the methodology reminded me about my own presentation a few days ago for USP, where, despite the majority of life science students, there were a few arts students lurking in a corner of the conference room. And as much as I thought I had "dumbed' down the technical aspects of my presentation, it never occurred to me that mere utterance of the words "copulation", "virgin", "courtship" and "sperm" would have sparked the giggles they did, always from that particular corner. And they were boys leh.

Haiyaa, arts students. *Tut tut*

1 comment:

YC said...

there in fact was only *ONE* arts BOY, and it was....
oh you know who.
Shrugs and quivers in disgust.