More tattoos, more sex?

In many cultures, the human body is not good enough as it is: it requires remodeling and marking of various types. Tattoos, piercing, scarification and other forms of bodily modification are widespread across contemporary human cultures, and they have long existed.

Archaeological and other prehistoric evidence indicates that head elongation, ear piercing and tattooing have been practiced for hundreds of years. Patterned blue dots appear in various places on the skin of Ötzi, the Neolithic “Ice Man,” and scientists theorize that the location indicates a possible healing function.

Tattoos among highland peoples in Southeast Asia can protect the bearer against harm such an animal attack or can enhance one’s intelligence, strength or attractiveness. Cultural anthropologists have written extensively about body modifications representing human agency and choice as well as being oppressive “inscriptions,” such as foot binding, breast enhancement or genital cutting. Evolutionary anthropologists seek to understand how such behaviors as tattooing and piercing relate to biological fitness. The bottom line: do tattoos and other forms of body modification help people find a mate and reproduce their genes?

Anthropologist Slawomir Koziel and colleagues propose two hypotheses about tattoos and piercing drawn from evolutionary biology:

1. because tattoos and piercings involve biological risks due to possible blood-borne infections, they signal a higher biological quality
2. tattoos and piercing increase a person’s physical attractiveness or hide a problem with appearance specifically low body symmetry (high symmetry is taken as an indicator of healthy development).

To test these hypotheses, the researchers recruited participants in two tattoo salons in two cities in Western Poland. A total of 64 men and 52 women took part. All reported having tattoos or piercings beyond earlobe piercing. All were Polish, and the mean age was 23 years. Most had completed secondary school and 25 were postgraduates.

A control group was composed of 38 men and 48 women who had no tattoos or piercing. All participants completed a questionnaire asking about basic demographics: age, gender, place of birth and residence, education and marital status. Their second and fourth digits were measured, as was finger length from basal crease of the digit to the tip along the ventral surface of the hand. These measurements were used to create a composite index for body symmetry.

Among males, the most common location for tattoos was the upper and lower extremities. For females, it was the back and stomach. Men had more tattoos covering more of their body than women did. Piercings were most often on the face for males and on the stomach for females.

Results offered no support for the first hypothesis about attractiveness for either the men or the women. In terms of the second hypothesis, tattooing among the men was positively related to higher body symmetry and thus appears to be an “honest signal” of biological quality. Among the women, no relationship was found. The authors see the need for further research on the biological function of tattoos/piercing especially among men in different social contexts and in varying social strata in relation to the men’s personality, risk-taking behavior and hormones. The body symmetry measures used in this study could also be improved upon in terms of assessing “genetic quality.”

Food for thought for readers who have opted, or not opted, for body modification: Do you find either hypothesis compelling?

Photo: “Ben (01), Tattoo Artist”, from Flickr, licensed for Creative Commons.