The peacock's tail is undoubtedly the most famous example of biological honest signaling. Charles Darwin argued that such appendages could not have evolved via natural selection, as they do not augment an organism's likelihood of survival. Instead, he proposed a parallel evolutionary process, sexual selection, as the means by which such traits evolve. Sexual selection involves the recurring mate choice of one sex (typically females) such that they favor individuals who possess particular morphological traits and/or who display desired behaviors. Hence, sexual selection confers reproductive advantage (rather than survival benefits). In the case of the peacock's tail, the biological signals are tantamount to a neon sign advertising genetic quality (via the size of the tail, its iridescent coloring, and the symmetric patterns).
In 1975, Amotz Zahavi added an important piece to sexual selection. He noted that in order to be honest signals of genetic quality, some sexually selected traits must impose a handicap on the signaler. Otherwise, fakers could "scam" the ladies into thinking that they are optimal males when in reality they are low on the genetic totem pole. Hence, this is what is meant by a costly signal, an honest signal, or more generally Zahavian signaling.
I have argued elsewhere that many forms of conspicuous consumption are tantamount to Zahavian signaling (cf. chapter 3 of my book The Evolutionary Bases of Consumption; see also Miller, 1999; Sundie et al., in press). In other words, some purchases are meant to advertise one's high social standing in no uncertain terms. Pretenders need not apply! While conducting research for my forthcoming trade book The Consuming Instinct: What Juicy Burgers, Ferraris, Pornography, and Gift Giving Reveal About Human Nature (Prometheus Books, 2011), I delved into the fascinating world of high-brow art collecting to see whether I could detect elements of honest signaling. I started off exploring who owned the most expensive paintings (see the Wikipedia entry here). Note that most individual owners are men (and generally they are not anonymous). This seems to suggest that paying $100+ million for a painting might constitute a form of "peacocking." This does not exclude the possibility that art pieces are at times purchased as investments, nor does it reject the possibility that art collectors reap aesthetic pleasure from owning such pieces. That said it might be a stretch of logic to argue that the aesthetic utility derived from looking at a beautiful painting in one's home could ever equal $150 million. Hence, it is more than likely that men constitute the overwhelming majority of high-end art collectors because such an activity serves as an honest signal of their social standing.
Sundie, J. M., Kenrick D. T., Griskevicius, V., Tybur, J. T., & Vohs, K. D. (in press). Peacocks, Porshes, and Thorstein Veblen: Conspicuous consumption as a sexual signaling system. Journal of Personality and Social Psychology.
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