Despite the promise of evolutionary discussions of tattooing in my blog title, I have yet live up to the provocation it inspires…until now. Honestly, I’ve had a post about Iban tattooing & sexual selection in the back of my mind for a while & I think I may have casually mentioned it before, but a new paper has just been published in Review of General Psychology by Rachel Carmen, Amanda Guitar, & Haley Dillon that is prompting me to write on the subject. By the way, once again the world is small, as the authors are out of the SUNY New Paltz evolutionary psychology program, the first of which appears to share 18 Facebook friends with me, & they are no doubt students of Glenn Geher.
In a nutshell, the authors review data on tattooing cross-culturally & synthesize it with extended phenotype & costly signaling theory & propose two complementary models of tattooing based on evolutionary principles. The first, the “human canvas” hypothesis, utilizes Dawkins concept of extended phenotype to suggest that body ornamentation signals symbolic capacity associated with either group affiliation or individual expression. The second, the “upping-the-ante” hypothesis, draws on costly signaling to suggest that tattooing & other immunologically stressful forms of body modification advertise one’s fitness. This is especially pertinent in our current environment where healthcare has reduced the pathogen-load and hence the pressure to utilize “good genes” approaches in mating strategies. In environments where health is relatively stable, purposefully stressing the immune system is a way of “upping-the-ante.”
I would add that the “upping-the-ante” model can be linked to the behavioral immune system concept. Experimental studies of the behavioral immune system have demonstrated that heterosexual female attraction to indicators of high genetic-quality in males (e.g., masculinized faces) increases when primed with disgust (Watkins et al. 2012). What this means is that when the playing field is relatively even and environmental pathogen-loads are low, presenting minimal danger, mating constraints are reduced and all offspring have a relatively high chance of survival. But when pathogen-loads are higher, as signified by festering wounds, fecal material, or other “disgusting” potential disease vectors, mating constraints are increased, and there is an increased female tendency to prefer male mates whose genetic quality will increase the probability of offspring survival. Thus tattooing and costly body ornamentation may alter that playing field by enabling individuals to advertise their immunological quality relative to others through broadcasting their ability to withstand trauma or pain.
I have been researching & writing on this topic lately, both conducting research on the “innoculation” hypothesis, which is related, & making a theoretical case for cultural congruence of North American tattooing practices & functions. The innoculation hypothesis is the biological correlate of the upping-the-ante theory. Whether the Carmen et al models suggests that tattooing advertises underlying quality, the innoculation theory is based in traditional warrior tattooing actually confers strength & protects against enemy arrows. We suggest that tattooing not only stimulates immunological reaction & demonstrates ones capacity to withstand stress & heal but that it induces an allostatic response, resulting in a higher threshold for stressor-related trauma to the system. To test this, we are measuring salivary immunoglobulin A (SIgA) before & after tattoo sessions in individuals with varying tattoo experience. IgA is the antibody that lines the respiratory & gastrointenstinal tract as a front line against pathogen. It is metabolically expensive but tightly conserved in mammals, suggesting its importance as a defense against common ailments. When the body is stressed & energy is allotted elsewhere, IgA production drops, & we get sick. We suggest that people who have habituated their bodies to stress, such as athletes or tattoo enthusiasts, will have smaller drops in SIgA due engaging in a stressful activity (pre- to post-tattoo session, for instance).
French voyageur Jean-Bernard Bossu touches upon all these models to some extent & is among my favorite first-hand examples, as it is uniquely anthropological in tone (relatively detached & includes both participation & observation without being overly judgmental). Bossu’s collected letters document his travels thru the Louisiana territory from 1751-1762, during which he was adopted by the Arkansas Indians & tattooed as an indication of his status as a soldier. He received a roe-buck on his thigh, which was a totemic symbol of the group for those who have proved themselves in battle. He said,
“I cannot tell you how much I suffered and how great an effort I made to remain impassive. I even joked with the Arkansas women who were present. The spectators, surprised by my stoicism, cried out with joy, danced, and told me that I was a real man. I was truly in great pain and ran a fever for almost a week. You would never believe how attached to me these people have become since then” (Bossu 1771).
As a testament to the importance of this tattoo as a symbol, Bossu also tells a story of a native who got a tattoo that falsely advertised deeds he did not do to impress a girl he was wooing. This so angered the tribe that they held a council & decided to flay the tattoo skin off the man to prevent this misrepresentation. According to Bossu, he felt sorry for the native used a technique unknown to the tribe to remove the tattoo without pain. This latter intervention is strange, given Bossu’s earlier claims that native tattoos could not be removed. Some have suggested that Bossu is parodizing the writings of Dumont, another French voyeuger of the era. However, the joke is lost on me & merely strikes me as odd without more context. Nevertheless, Bossu’s descriptions remain among the more enlightening about early contact tattooing in North America, & the forms & functions cited are remarkably consistent across time, lending credence to Carmen & colleagues’ hypotheses.
There are few other models out there that utilize evolutionary principles to explain tattooing, so Rachel Carmen & her colleagues have made a welcome contribution to the field.