Why advanced culture might sometimes promote hypercredulity

What is it about?

Although social learning, culture, and traditions are found in animals, why humans seem to be the only species that builds on knowledge and technology over generations to the degree that we do is still not fully understood. To try and understand more about this puzzle we organized a computer tournament in which programmed entries specified when to learn new knowledge and when to refine (i.e. improve upon) existing knowledge. We found a ‘refinement paradox’: while using refined, i.e. highly improved, behavior was beneficial to individuals, it was not beneficial to be the one doing the refining. Entries that refined selectively, only under limited conditions, did well while refinement levels increased, but once refinement was high simple entries that did not refine thrived. This result might explain why the type of cumulative culture we see in humans is rare in nature: sophisticated strategies for improving knowledge are initially advantageous, but once complex culture is common it pays to conform to the behavior of others and copy blindly at which point further innovative progress is impeded.

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Photo by note thanun on Unsplash

Photo by note thanun on Unsplash

Why is it important?

The paper describes a major and long-standing collaborative project that has involved virtually all of the leading authorities in the field of cultural evolution. Our goal was to investigate a fundamental unresolved problem relevant in evolutionary biology, psychology, anthropology and social science, namely ‘Why is cumulative culture and complex technology found only in humans?’ While animals like chimpanzees and whales possess learned traditions, only human culture generates complex advanced technologies that no individual could invent alone. Investigation of this issue has been hindered by the difficulty of studying cumulative culture, an inherently complex, large-scale, long-term process. The approach we took to resolve this is innovative – we organized a major international competition, in the form of a computer tournament, open to all, in which entrants propose a learning strategy specifying when to learn anew and when to refine (i.e. improve) existing knowledge. The entered strategies were pitted against each other in a computer simulation to see which works best in a dynamic simulated evolutionary environment that models cumulative culture, and the winner was given a €25,000 prize. The tournament attracted huge attention and was a major international and multi-disciplinary event, with 51 eligible entries from a broad range of academic disciplines (anthropology, biology, data science, ecology, economics, ethology, computer science, journalism, mathematics, neuroscience, social science) and from industry. The significance of the tournament is that it provides the first compelling evolutionary explanation for why cumulative culture is restricted to our species. Our findings reveal a ‘refinement paradox’: refined (i.e. technologically advanced) behavior afforded higher payoffs as individuals converged on a small number of highly successful behaviors or technologies, but refining did not generally pay. Only ‘smart’ (i.e. cognitively demanding) refining strategies, capable of evaluating the likely costs and benefits of refinement, could excel when technology was simple. Cumulative culture is rare because strategies for improving technology must be cognitively sophisticated to be advantageous in animal societies, but animals rarely possess such cognition. The tournament also explains hitherto puzzling aspects of human cognition. Psychologists and cognitive scientists have been struck by human credulity and the ‘blind’ nature of human imitation. Experiments show that humans, but not other animals, commonly imitate causally irrelevant actions (a phenomenon known as ‘over-imitation’) and assume that others are there to teach them. Relevant to these observations, we found that simple copying strategies could thrive in technologically advanced (but not technologically simple) environments, which suggests that blind imitation is more adaptive for humans than for other animals. Seemingly, humans live in culturally evolved environments in which blind copying is especially adaptive. This allows us to provide a novel evolutionary explanation for the ‘hyper-credulity’, ‘over-imitation’ and ‘natural pedagogy’ reported in humans but not found in other animals.