Miller’s Spent: Sex, Evolution, and Consumer Behavior


Jason Collins


June 15, 2011

Geoffrey Miller’s main thesis in Spent: Sex, Evolution and Consumer Behavior is that the conspicuous consumption we use to signal traits such as intelligence, agreeableness or conscientiousness is unnecessarily indirect. Instead, we should use our evolved abilities to show these characteristics through humour, communication and interaction with others. Miller summarises his position as follows:

Consumerist capitalism is largely an exercise in gilding the lily. We take wondrously adaptive capacities for human self-display - language, intelligence, kindness, creativity, and beauty - and then forget how to use them in making friends, attracting mates, and gaining prestige. Instead we rely on goods and services acquired through education, work, and consumption to advertise our personal traits to others. These costly signals are mostly redundant or misleading, so others usually ignore them. They prefer to judge us through natural face-to-face interaction. We think our gilding dazzles them, though we ignore their own gilding when choosing our own friends and mates.

I am sympathetic to Miller’s general argument. A few minutes of face-to-face communication can undo many signals, such as our choice of clothing or car. However, status, wealth and power are still qualities that matter to a mate. Given two mates of equal genetic value, the one with the higher resources or status would be expected to be better able to provide for the child. Through human history, parental wealth has had a strong correlation with child mortality (possibly only breaking down in developing countries in recent decades). There will be some rate of trade-off between resources and genetic quality, and we will want to signal our level of resources.

There are also limits to the accuracy of face-to-face assessment. While I may seem hard-working and conscientious, the fact I have worked to the top of my business is evidence of this. Can I fake conscientiousness through a few dates more easily than I can through a decade in a top company? Do I then need the BMW to show that I am actually successful in this company as opposed to being at the bottom of the pile?

Miller is optimistic that people can move away from the consumerist culture. Tongue-in-cheek, he suggests tattoos of our intelligence and big-five personality trait scores. While this may be a more accurate signal, for a signal to be useful we need to consider the recipient. Are they more aroused by the sight of my IQ score, my bank statement or the BMW acquired due to my intelligence and wealth? If they prefer the BMW signal, despite its lower accuracy, it would be a poor strategy on my part to deviate. As Miller notes:

There seems to be no easy shortcut through our person-perception systems. We have to feed them the kinds of social stimuli that they evolved to expect, and institutionally validated trait tattoos are not among those stimuli.

One thread of the book I appreciated is Miller’s argument that government should remove any barriers to checking out of consumer culture. In some ways, that is the appeal of the libertarian state - those who wish to check out can. While Miller has this freedom-supporting thread, he is not averse to Pigovian taxes on a raft of products. He writes:

All negative externalities are, by definition, encroachments on other people’s lives and property. So, even hard-core libertarians who believe that governments should do nothing more than protect people from such encroachments should be willing to accept a consumption tax specifically designed to counteract such encroachments. From this viewpoint, the consumption tax is not paternalistic meddling. Rather, it is a classical “Pigovian tax” designed to correct the negative externalities of market activity. … From that perspective, it seems reasonable that governments should impose consumption taxes designed to neutralize each product type’s externalities. In other words, we should be free to choose what we buy and how we live, as long as we pay the fair price for every harm we do to others in the process.

If we are going to raise tax revenue, Pigovian taxes are one of the more efficient ways to do it. However, Miller spots my number one concern:

Skeptics might object that to set appropriate product-specific consumption tax rates would require a vast new government bureaucracy. We would need thousands of economists, statisticians, actuaries, and psychologists to measure all the externalities, risks, and costs of every product class. That is true, but that is precisely what we need: good solid data about the true social and environmental costs of the goods and services we buy. If we don’t collect and analyze such data, all arguments about the social and environmental effects of different policies are just blather. They can’t be evidence-based if there is no evidence.

Miller’s view of a product-by-product assessment would seem to offer massive opportunity for companies to lobby for different taxes on competitor’s products as theirs has a longer-life or is more environmentally friendly. And I’m not sure it is required. As an alternative, taxes at the source, such as a carbon tax, would allow the market to allocate the carbon price across products. To address the short life-span of products, you make people pay the costs of their disposal. The bureaucracy could be smaller than it is.

Some of Miller’s other proposals, such as subsidies for positive externalities like fitting airbags to cars, might also be better addressed by looking at the incentives.  If we put more of the burden of health care of individuals, this increases their incentive to act safely. They can choose their own balance between airbags and speed - or possibly an insurance policy that gives them a discount because they have airbags.

Miller ends the book with a series of exercise for the reader. You can go through a check-list of the experiences of our paleolithic ancestors, assess what is the purposes of your consumption and consider alternative signalling techniques. It is a useful set of exercises and highlights what is the most useful message of the book - as you go to make each purchase, consider what you are intending to signal by it and whether there is a more effective way to send that message. Are you simply sending the same signal as everyone else? In Miller’s words:

You anticipate the minor mall adventure: the hunt for the right retail environment playing cohort-appropriate nostalgic pop, the perky submissiveness of sales staff, the quest for the virgin product, the self-restraint you show in resisting frivolous upgrades and accessories, the universe’s warm hug of validation when the debit card machine says “Approved,” and the masterly fulfillment of getting it home, turned on, and doing one’s bidding. The problem is, you’ve experienced all this hundreds of times before with other products, and millions of other people will experience it with the same product. The retail adventure seems unique in prospect but generic in retrospect. In a week, it won’t be worth talking about.

If your intention was to send a signal with this product, forget it. But if it is useful, that’s another thing.