This article was first published in the April 2016 issue of WIRED magazine. Be the first to read WIRED’s articles in print before they’re posted online, and get your hands on loads of additional content by subscribing online.
In the game of life, survival is only part of the battle. One must also succeed in attracting a suitable mate. Animals use a broad range of strategies to advertise themselves in the mating market. In some instances, visual cues highlight a morphological feature – for example, the peacock’s tail. Auditory courtship displays are common across many types of animal, including birds (song), frogs (vocalisation), monkeys (calls), whales (song) and crocodiles (bellowing). Many species employ visual and auditory cues as part of their elaborate courtship displays. Specific behaviours are also part of the signalling repertoire and might include fighting (rams), dancing (red-capped manakin), applying make-up (flamingos) or creating art (satin bowerbird). In some instances, courtship displays take place within a communal space known as a lek.
Heterosexual humans exhibit traits and behaviours that are at times analogous to those expressed by animals. In my research, I demonstrate such realities within the consumer realm. Specifically, humans use sex-specific products as sexual signals (eg men show off their luxury sports cars and women beautify themselves). My colleague John Vongas and I examined how men’s product-related showing off affects their testosterone levels. For example, young men drove a Porsche and an old sedan in downtown Montreal (a human lek) and on a deserted motorway (non-lek). After each test, we collected salivary assays to measure possible fluctuations in their testosterone levels. In both settings, men’s testosterone levels increased significantly after driving the Porsche, as this endocrinological response corresponds to that experienced by individuals who win intrasexual competitions.
In addition to serving as a conduit for peacocking, luxury cars alter men’s perceived morphological features. In an ongoing project with Tripat Gill, a professor at Wilfrid Laurier University in Ontario, we created two versions of a man’s online-dating advertisement. The only difference between the two versions was the visual depiction of the target’s stated favourite possession: an expensive red Porsche or an inexpensive red Kia. Participants were asked to evaluate the man along several metrics including his perceived height. For the Porsche version, men reduced his height (status contraction effect) and women increased it (status elongation effect). This is precisely what an evolutionary perspective would predict. Status is a primer for male-male intra-sexual rivalry, and since male height is associated with higher status, men will derogate male competitors who are exhibiting cues of social status. On the other hand, the women’s visual system is tricked into imagining that men who are associated with high-status products are taller than might be the case.
Although in most species males are more likely than females to engage in elaborate forms of sexual signalling, this does not imply that females don’t do so as well. When in oestrus, females of many species exhibit visual cues – for instance, enlarged and engorged genitalia – to communicate sexual receptivity. Miami University’s Eric Stenstrom and I tested this principle in the context of women’s beautification practices. We reasoned that women’s menstrual cycles should affect the extent to which they advertise themselves via beautification acts, such as wearing cosmetics. We tracked behaviours, preferences, desires and purchases across 35 consecutive days (the average menstrual cycle is 28 days). Beautification, behaviours and purchases were greater in the maximally fertile phase of their cycles.
In a wide array of species, nuptial gifts are central to the courtship ritual because of their signalling value. In many instances, food is the gift of choice. The calories-for-sex trade is replete in the animal kingdom, but perhaps the most “romantic” instantiation of this phenomenon is sexual cannibalism – largely found among spider and insect species – wherein males are devoured during copulation. For humans, gift giving is a universal ritual laden with evolutionary implications. One way for a man to reduce his likelihood of a second date is to act cheaply on a first. Gill and I explored gift giving via an evolutionary lens1. First, we examined the manner by which people allocate gift-giving budgets across prospective recipients. Mates received the largest chunk. Second, we explored sex differences in the motives that drive men and women to offer gifts. Men were more likely to offer gifts for tactical, mostly signalling reasons: displaying financial resources; creating a good impression; and showing signs of long-term interest as a means of seduction.
The evolutionary roots of human gift giving extend beyond an investigation of sex differences. When my wife was pregnant with our first child, we proudly posted the ultrasound images on the door of our fridge. Although it is impossible to establish whether the image corresponded to an extra-terrestrial, a dinosaur or a kangaroo, my mother-in-law unequivocally discerned a striking paternal resemblance. She was unconsciously appeasing my potential angst associated with paternity uncertainty. In an ongoing study with three Israeli co-authors, I show how paternity uncertainty shapes gift-giving practices2. Using data from 30 Israeli weddings, we show that the matrilineal side of the brides and grooms offer larger monetary gifts than their patrilineal counterparts. Genetic assuredness is at the root of this.
Consumer behaviour is a powerful realm from which to explore our biological heritage. The products that we purchase as sexual signals, the gifts that we offer to loved ones, the cultural products that captivate us – from song lyrics to movie plotlines – all speak to shared forces that unite the global consumer under an evolutionary umbrella. To slightly rework Charles Darwin’s famous assertion: “Consumers bear the indelible stamp of their lowly origins.” In many ways, members of Homo consumericus are not that different from their animal cousins.
- Saad, G, & Gill, T. (2003). An evolutionary psychology perspective on gift giving among young adults. Psychology & Marketing, Vol. 20, pp765-784 2. Saad, G, Tifferet, S, Meiri, M, & Ido, N. Gift-giving at Israeli weddings as a function of genetic relatedness and maternal lineage, 2012
