If tattoos have been around for possibly about 7000 years (Serup et al.,
Thomas Richie Richardson

I agree that there are unlikely to be adaptations that specifically target tattoos. Perhaps I gave that impression by equating the process with the peacock’s tail which, of course, evolved as a physical honest signal of quality. Instead, I think the tattoo is likely a culturally agreed-upon honest signal, functioning in a similar way but with different origins. Some cultures use tattoos, others use scarification, but it all cases it seems to me that these are honest signals because only the strongest or healthiest people can withstand the ‘injury’. I mentioned a similar concept in my paper on scarring: the academic fencing popular in certain parts of Germany (historically and, to some extent, today). This practice can result in scars on the face, which are prized. But for people who don’t know the reason for the scars, the message will be obscure.