Thorstein Veblen proposed a social evolution of economic systems in his 1899 book, The Theory of the Leisure Class. Veblen described the social stratification of late nineteenth-century society into the middle and lower classes of industrial workers who were responsible for producing valuable goods and the upper-class owners of industry who were often engaged in useless activities that did not contribute to production or society. Veblen proposed that these dynamics were legacies of the “predatory” behaviors from humans’ barbarian and tribal past. Growing up in a Norwegian American community of thrifty, practical, and utilitarian people facing anti-immigrant prejudice, Veblen harshly satirized American consumerist culture. Veblen coined the terms “conspicuous consumption” and “conspicuous leisure” to describe the wasteful habits of the upper classes in amassing and displaying expensive goods that did not have inherent practical benefits and devoting time to pursuits such as sports and fine arts. The purpose of these socially conspicuous displays and behaviors was to advertise one’s membership in the upper, leisure class, as only the very wealthy could afford them.

Veblen was inspired in part by Charles Darwin’s theory of biological evolution. Darwin himself was greatly puzzled by what he considered wasteful investments of energy in elaborate physiological displays. He saw these features as the greatest threat to his theory of natural selection. Why would something like the peacock’s tail feathers evolve, as they actually threatened survival because of their impediment to foraging and avoiding predators? Darwin was so troubled by this dilemma that the sight of a peacock’s tail feather would make him feel sick. Darwin later realized that these features provided a reproductive advantage, leading to his theory of sexual selection, including the processes of inter-sexual selection and intra-sexual competition. Later scholars have elaborated on the function of these features as costly signals, they are attractive to potential reproductive partners because they advertise superior genomic-environmental compatibility and are only possible when an individual has surplus immune and energetic capacity.

Veblen proposed that inherited psychological mechanisms created associations between conspicuous consumer goods and wealth-based social prestige. Darwin realized that energetically costly physiological features are attractive to reproductive partners because they advertise mate quality. Evolutionary Psychologists have combined these models in an ultimate (evolutionary) explanation of the audacious displays of wealth described by Veblen. Men purchase and display luxury consumer goods because these products signal their economic power. Such resource displays enhance their attractiveness to potential reproductive partners because they predict resource investment in offspring. Human children require enormous parental investment, we have an extended period of development and may take decades of maturation before we are net providers of calories or other resources. Paternal investment, the resources and care provided by fathers, is very important for enabling children to survive and thrive.

There is considerable evidence for the relationship between men’s socioeconomic status and their abilities to acquire mates and produce offspring. Several large cross-cultural studies demonstrate that women evaluate prospective partners’ socioeconomic status more so than men do. Men’s socioeconomic status predicts their reproductive success (their proportion of offspring in future generations) across a wide variety of societies with varying economic systems and levels of technology. There is likely a general relationship between a man’s wealth and the level of resources he invests in his children.

Evolutionary psychologists have even made a direct analogy between men’s displays of luxury goods and the grand display of the peacock’s tail feathers. However, there is a fundamental challenge to this analogy and model. The peacock’s tail feathers are a signal of the bird’s genetic qualities, rather than investing resources in or caretaking of offspring by the male bird. The feathers are an example of secondary sex characteristics, features that appear in animals at sexual maturity but are not directly part of the reproductive system. These ornaments and armaments facilitate intra-sexual mating competition. They enable quick and reliable assessments of physiological quality, physical strength, social status, dominance, and aggressiveness by competitors and potential reproductive partners. Sometimes these features are involved in direct physical contests, such as the antlers of the deer family.

The more exaggerated secondary sex characteristics are in males across species, the more males focus their energies on mating competition (acquiring mates), and the less they invest in the care of offspring. A similar pattern of individual variation is evident within humans. Men with greater facial masculinity and lower-pitched voices have more sexual partners, more short-term sexual partners, and more partners in sexual affairs. African hunter-gatherers with lower voice pitch have more offspring than those with higher-pitched voices. Highly masculine men are more attractive to women for brief sexual affairs, but they are also more likely to cheat on their romantic partners, attempt poaching of other men’s romantic partners, and provide lower paternal investment in their own offspring.

Life History Theory is a powerful explanatory framework within evolutionary theory and is central to modern biology. This framework was developed to explain the wide variation in reproductive strategies across species, ranging from brief lifespans with high fertility rates to long lifespans and high investment in a small number of offspring. Greater unpredictability in environmental factors such as the availability of resources and death from predation leads to accelerated growth and reproduction. Those in more stable environments can pursue more future-oriented strategies. An organism’s energetic resources are limited, and thus the more invested in one area of life, the less there is to invest in others. There is a tradeoff between the somatic efforts of building and maintaining a body and the reproductive effort of contributing to future generations. Within reproductive effort, energies invested in the competition for mates (mating effort) is inversely related to that invested in offspring (parenting effort).

This creates a problem for the standard explanation of conspicuous consumption as an indicator of paternal investment in evolutionary psychology. Peacocks do not provide any paternal care, instead, they have metatarsal spurs on their legs that they use as weapons in territorial fights with other males. Extravagant luxury displays could represent investments in mating competition, which is inversely related to tendencies to invest in children. How then can one distinguish between signals of male mating effort and predictors of paternal investment? The solution may be to re-examine the relationship between luxury displays and the peacock’s tail feathers. Perhaps the phenotypic features of the consumer products themselves could be parallel in form and function to the secondary sex characteristics across species. Consumer products mimicking the physiological properties of male secondary sexual characteristics (e.g., features with exaggerated size, elaborate coloration, and lower-pitched sounds) may indicate investment in mating competition. Indeed, a survey item on tendencies to wear flashy clothes loads strongly on scale assessing mating effort.

A recent series of studies tested predictions derived from this phenotypic mimicry hypothesis in carefully controlled experiments. Participants viewed polo-style shirts with small and large versions of a luxury clothing brand logo in randomized order. In some of the studies, participants predicted the characteristics of the man who owned each shirt. In another, male participants were asked which shirt they would wear in specific social contexts and female participants were asked which shirt they thought men would be more likely to wear. Men owning the large logo shirts were rated higher on mating effort, lower on parental investment, higher on interest in brief sexual affairs, lower on interest in long-term committed romantic relationships, higher in attractiveness to women for brief sexual affairs, lower in attractiveness to women for long-term committed relationships, and higher in developmental environment unpredictability compared to men owning shirts displaying a smaller logo. This pattern is completely consistent with the life history-based model. In another study, men were most likely to wear the large logo shirt when then competing for social dominance or attempting to attract a sexual partner. They were least likely to wear the large logo shirt when meeting their potential in-laws or applying for a job. Such results indicate the strategic use of luxury displays to signal features consistent with social goals.

The strong and consistent pattern of results demonstrates support for the phenotypic mimicry hypothesis and challenges the notion that men’s luxury displays are a reliable signal of their paternal contributions. Of course, it will be important to further test predictions from this theoretical model. These studies used a carefully controlled experimental design with limited stimuli to isolate the cause of differences in perceptions and strategies. Given the scope of relevant issues, a host of different study designs could be used to test various implications of the model. Overall, these studies demonstrate the power and potential of Life History Theory in applying evolutionary theory to models of human psychology and behavior.