What explains human attitudes toward economic exchange? One explanation is that economic attitudes directly follow the shape of evolved human intuitions. For example, Boyer & Petersen (B&P) propose that coalitional psychology (a tendency to favor one's own group in competition with other groups) leads to a perception that, in international trade, foreigners disproportionately benefit at the expense of own country citizens.

Previous work has also studied how psychological dispositions shape attitudes toward markets and their regulation (Caplan Reference Caplan2008; Hirshleifer Reference Hirshleifer2008; Hirshleifer & Teoh Reference Hirshleifer and Teoh2009; Reference Hirshleifer, Teoh, Baker and Nofsinger2010; Rubin Reference Rubin2002). For example, the three papers by Hirshleifer and by Hirshleifer and Teoh propose the psychological attraction approach to economic and financial regulation. This holds that regulation is a result of the psychological dispositions of political participants and regulators, and the cultural evolution of regulatory ideologies whose spread is influenced by these dispositions. Like B&P's target article, this work emphasizes that evolved psychological mechanisms underlie economic attitudes. B&P go much further, by systematically and insightfully analyzing the evolutionary psychological sources of human economic beliefs. However, in doing so, B&P underweight the causal importance of cultural evolution, as influenced by social transmission biases.

As B&P recognize, evolved psychological dispositions tilt, but do not directly determine, how people think about economic issues. The same evolved human psychology that gives us socialists also gives us libertarians, as well as dramatic variations over time in the prevalence of different beliefs. For example, communism for a time dominated a large part of the globe before receding. Just as genes and psychological dispositions do not directly and fully determine whether someone is Christian, Buddhist, or Marxist, human evolved psychology alone does not fully determine economic attitudes.

In the phrasing of Hull (Reference Hull1980), genes (and individual-level psychological dispositions) determine a reaction norm – that is, a stochastic relation between environmental input and the likely range of an individual's beliefs. An instinct for reciprocity, for example, can tilt people toward viewing economic exchange as beneficial, but other cultural inputs can easily overturn this tilt.

This is not to deny that evolved psychological dispositions profoundly influence which ideas are appealing, and thereby which will spread. B&P have advanced our understanding of these individual-level propensities. These include, for example, ownership intuitions and coalitional psychology, which play out in intuitive ways. But psychological propensities can also feed into economic attitudes in much less intuitive ways, by influencing cultural transmission. For example, conformist transmission can support ideas which, taken in isolation, are not appealing, if they can somehow become popular in the first place.

So, to understand the evolution of economic attitudes, we need to understand biases in the social transmission of ideas. Economic attitudes are culturally transmitted, and folk economic ideas are often linked together as ideologies, such as socialism or free market ideologies. This means we need to understand how culture evolves, and an explicit focus on the cultural, not just the genetic, evolutionary process to understand the evolution of economic issues. (On social transmission biases, see, e.g., Boyd & Richerson Reference Boyd and Richerson1985).

Consider, for example, simplistic, “catchy” ideas. At the individual level, these are easy to absorb, but their weak logic may make them less attractive. So there is no conclusive general presumption that individuals will adopt simplistic ideas. However, simplicity is often an advantage in social transmission. Simple ideas are easy to remember and communicate to others. Furthermore, bandwidth constraints may force subtle ideas to be reduced in communication to un-nuanced versions. Simple ideas become more prevalent. Furthermore, owing to the truth effect (e.g., Schwartz Reference Schwartz1982), ideas that an individual hears often are more likely to be perceived as correct. So basic psychological properties – the ease of remembering and describing simple ideas, and the truth effect – increase the cultural fitness of simplistic economic ideas.

Simple ideas or catch-phrases are common in the economic realm: for example, “property is theft,” or, alternatively, “the only handout I want is the government's hand out of my pocket”; that the system is rigged to favor the 1%, or, alternatively, that the death tax unfairly taxes income a second time. Public economic discourse is not limited to sound-bites, but casual observation suggests that they are disproportionately influential.

To see how social transmission biases can induce surprising cultural evolutionary outcomes, consider a hypothetical example. Suppose that people like to talk more about their investment successes than their failures. Then listeners will hear more stories from their friends about large profits than about losses from active stock trading. If listeners neglect this selection bias in what is reported (there is much general psychological evidence of such neglect), they may conclude that ordinary people can easily profit by actively trading individual stocks. This argument is modelled formally in a working paper by Han et al. (Reference Han, Hirshleifer and Walden2018).

In this example, there is no psychological disposition directly pushing people toward believing that active stock market trading is a good strategy. Instead, psychological dispositions induce a bias in the social transmission process, and this social process causes cultural evolution toward active trading – a direction that is non-obvious based on individual level propensities.

B&P do thoughtfully and appropriately discuss cultural transmission processes, and they correctly recognize that the effect of evolved intuition on economic beliefs is probabilistic. However, when it comes to forming actual hypotheses, B&P's method is to move in a straightforward way from evolved psychology to folk beliefs. This is an important and valid approach if followed with appropriate caution. But our contention is that there is much additional value to be gained by considering how social transmission biases cause economic attitudes to evolve.

Another crucial element of a cultural evolutionary approach is that assemblies of ideas evolve (Dawkins Reference Dawkins1976; Distin Reference Distin2004). For example, socialism became much more contagious when Engels and Marx combined ideas about shared ownership of the means of production with the claim that the historical inevitability of socialism was a scientifically proven fact. The cultural evolution of more attractive economic ideologies is a key driver of economic attitudes – one that deserves more analytic attention.