The Misguided Belief that More Is Less

Plato argued that a city-state of more than 5,040 households would deplete resources to the point that families would need to be exiled. Centuries later, political economist Thomas Malthus, worrying about food supplies, argued for celibacy and reduced caloric consumption. Biologist Paul Ehrlich, who authored The Population Bomb, lost a very public wager on future scarcity.

The conviction that growing populations will strain resources and impoverish populations is both age-old and persistent. New work by Jason Dana of Yale SOM, George Newman of the University of Toronto, and Guy Voichek of Imperial College London explores the roots of this “depletionism,” as they call it, as well as one way to reduce its potency: in short, remind people that a larger population means not only greater strain on resources, but also more opportunities for efficiency.

“More people means more mouths to feed, but it also means more arms to work and more minds to innovate,” the researchers write in the Journal of Experimental Psychology. They define the oversight of this fact as “efficiency neglect,” and they “identify efficiency neglect as a cause of depletionism.” Priming people to consider efficiency gains partially counteracts the depletionist mindset.

The researchers investigate this line of logic through six lab experiments, the first four of which establish the prominence of depletionism in the American mind. These experiments essentially quizzed Americans on their beliefs about changing prices over time; they found that people vastly overestimate the cost of household goods today, “leading them to believe that those goods have become more costly over the last decades, when in reality, nearly all became less costly.” (The researchers asked people about the “real” costs of goods, meaning the amount of time an average American worker would have to work to afford each product, as a way to disentangle this measure from inflation.)

The fifth study refines this line of questioning to link efficiency neglect as a cause of depletionist thinking. (The researchers make clear that efficiency neglect is one cause, but not the cause, of depletionism.) In this study, a control group was asked to consider how the prices of six products (gasoline, chicken, refrigerators, eggs, electricity, and tomatoes) changed from 1980 to 2018. One treatment group was asked, in addition, to think about whether there are, for instance, more or less acres for growing tomatoes, per person, today than there were in the 1980s. A second treatment group was asked instead to consider whether agricultural practices have become more efficient over time.

Priming people to consider increases in agricultural efficiency — something that they are aware of but that does not rise to top-of-mind — reduces the degree to which people believe prices have been increasing. It does not, however, reverse this belief, supporting the notion that efficiency neglect is one of many factors that lead to depletionist thinking. Priming people to think about changes in demand — fewer acres per person — has no effect on what they think of prices, which suggests that depletionism is, in essence, our default setting.

One final study tied these results to the attitudes that flow from this belief, demonstrating how a depletionist mentality bleeds into opinions on immigration. Concerns over scarce resources generate anti-immigrant sentiment, while “reminding people to consider the effects of population growth on innovation and labor can engender more favorable attitudes regarding immigration,” the researchers write. “Therefore, while depletionist beliefs appear to be pervasive, the present studies demonstrate that they can be mitigated by prompting people to consider what they already know.”

The researchers are upfront about the fact that policy opinions on something as complex as immigration are multifaceted, and that depletionism is not the only factor influencing views on the subject. More broadly, they are not trying to make the claim that life is easier today than it was four decades ago. Indeed, many notable goods and services — education, real estate, childcare — have gotten more expensive over time. But the work helps pinpoint one of the reasons people are generally pessimistic about the economy, and the way in which this pessimism affects policy support.

The work also ties into a broader arc of research examining the divergence between how the general population and trained economists view the economy. This kind of comparison has been done in much greater depth in fields like physics and biology, where studies have shown common misperceptions about the paths traced by projectiles or genetic similarities within species.

The absence of attention to this topic in economics, Dana and his colleagues write, is unfortunate given the consequence of lay economic beliefs. “Even people who cannot plot the trajectory of objects dropped from airplanes usually avoid walking into walls,” they say. “Faulty economic beliefs, however, lead to bad policies. Throughout history and still today, they are used to support destructive strains of populism across the political spectrum.”

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