Tattoo and piercing as signals of biological quality

Abstract

Tattoos and non-conventional piercings are used in many societies. There are several social reasons for which people use these forms of body decorations (e.g., marking social status or signaling membership within a subculture). However, it is interesting why only some people within a group that uses body decoration as a badge of membership decide upon such decorations. Since both tattoos and piercings can present health risks (e.g., due to blood-borne disease transmission risk), we postulate that people who decide to have such a body decoration might have relatively higher biological quality and that tattoos/piercings can be an honest signal of genetic quality. The possible opposite hypothesis is the “attractiveness increase hypothesis,” according to which people use body decorations to increase their own physical attractiveness or to hide some shortcomings in their appearance (e.g., low body symmetry). To test these hypotheses, we compared body fluctuating asymmetry, which is considered a good measure of developmental stability, between individuals wearing tattoos and/or non-conventional piercings (n=116) and a control group (without such body decorations) (n=86). We found that majority of the absolute and relative fluctuating asymmetry indices had significantly lower values in individuals with tattoos/piercings than in the control group. This effect was strongly driven by males. Higher body symmetry of the men having tattoo or piercing indicates that this type of body decoration in the western society can be related to the honest signal of biological quality only for men. We did not find support for the “attractiveness increase hypothesis” for either sex.

Introduction

Human body decorations are used by men and women in many societies. For a long time, they have been studied mainly by cultural anthropologists. However, they can be also analyzed from the psychological and evolutionary biology points of view. As natural ornaments in many non-humans, such human body decorations as tattoos and piercings can be treated as potential signals that might be important in social and sexual contexts. Tattooing, piercing, and body painting were frequently used to mark social status (Gilbert, 2001), as for instance in ancient Mayan where body art was associated with royalty (Baudez, 2000), or belonging to some group, for example, used in different subcultures and by criminals, soldiers, slaves, and the nobility (see review in Schildkrout, 2004). In 19th century Europe for instance, tattoos were also used as occupational emblems or insignia of patriotism (Caplan, 2000). In modern western societies, however, the main piercing/tattoo purpose can simply be self-expression and identity (Armstrong et al., 2004, Greif et al., 1999). Although different social functions of body decorations are relatively easily recognized by scientists, it is interesting that only some of the people belonging to the particular subgroups decide to have tattoos or piercings. Since tattoos and piercings are related both to pain and to some health risk, between-individual differences in deciding to have a tattoo/piercing can be related to the variation of risk-taking proneness by different individuals. There is evidence that at least 20%–30% of piercings are linked to some infection or transmission of blood-borne diseases, such as hepatitis (Goldberg and Anderson, 2004, Stirn, 2003) and HIV (Kral et al., 2001). For instance, among Pace University undergraduates in New York, 17% had some bleeding, tissue trauma, or bacterial infection after piercing (see review by Stirn, 2003). Apart from infection, tattoos may also provoke allergic skin reactions to the dye (e.g., cinnabar), and there are also other complications after tattooing (e.g., sarcoid-like granuloma, malignant melanoma, or basal cell carcinoma at the tattoo site) (Montgomery & Parks, 2001). It is then possible that people who decide upon tattooing can afford such a risky behavior because they have relatively good biological quality. If this is the case, both tattoos and piercings can be body ornaments that in the human mate market (intrasexual competition and mate choice) may serve the evolutionary function of a handicap (sensu Zahavi, 1975, Zahavi, 1977), indicating its bearers' biological quality (Wohlrab, Stahl, Rammsayer, & Kappeler, 2007). In this study, we tested whether, in comparison with the control group, people who have tattoos and/or non-conventional piercings have higher biological quality measured by their body symmetry [i.e., the level of fluctuating asymmetry (FA)]. The best way to test whether the decision to have body decorations such as tattoos or non-conventional piercings (i.e., excluding ear lobe piercing) is made more often by people with higher biological quality is by looking into a society where body decoration decisions are made by the individual and are not imposed by group rules or social pressure.

On the basis of studies both on animals (Agnew & Koella, 1997) and on humans (Jones et al., 2001), it is presumed that low FA is related to developmental stability and may therefore signal good genes (Moller and Swaddle, 1997, Moller and Thornhill, 1997, Thornhill and Moller, 1997). This is because only organisms with relatively good genes can resist different factors that can affect body development. Such individuals may therefore retain higher bilateral symmetry than those with a badly adapted genotype or immunological response. FA seems then to be a very good measurement of developmental stability that is granted by high-quality genes (Fraser, 1994).

Due to the biological function of body decoration, two alternative hypotheses can be put forward:

• Tattooing and piercing signal an individual's biological quality—the “biological quality hypothesis.” In this case, one should expect that people wearing body decorations are more symmetrical (have lower FA).

• People use body decorations to increase their own physical attractiveness or to hide some shortcomings in their appearance (e.g., low body symmetry) or to redirect attention from some body imperfections—“attractiveness increase hypothesis.” Singh and Bronstad (1997, p. 414) also wondered whether “men and women increase their attractiveness to potential mates by choosing scarification designs to highlight or mimic symmetry of body parts.” In this case, one should expect that people using tattoos or piercings are less symmetrical (have higher FA) than those who do not have any body decoration.

These two hypotheses may however not be independent of sex. Since on the mate market physical appearance is more important in assessing women's attractiveness (e.g., Buss, 1989) and social status (e.g., relative to a group) is more important in assessing men's attractiveness (Feingold, 1992), it is possible that the first hypothesis may be appropriate for men and that the second may be appropriate for women. In this case, one should expect sex interaction in FA between people wearing body decorations and those who do not use tattoos or piercings.