Example: Why imaginary worlds? 

In many animals, juveniles are more exploratory. This is the case because exploration is most adaptive when the individual knows little about the world, and juveniles from all species have less knowledge than adults. But juveniles from different species don’t explore at the same rate or to the same extent. They argue that species with parental care explore more because the major costs associated with exploration (e.g., resource shortage risk) are outweighed by parental caregiving investments.

Exploration is most valuable in more affluent and safe environments. In unsafe and poor ecologies, exploration is very risky, notably because if exploration doesn’t pay off, one is left with nothing. Relatedly, the opportunity costs of exploration are higher in scarcity because one is better off providing for more pressing needs. Conversely, in more affluent and safer ecologies, such risks are lower: when surrounded by more resources, individuals can afford to lose some of them in the short-term.

They argue this reasonning explains why imaginary worlds are prefered by younger people and emerged in economically developed countries. they also showed that films with imaginary worlds are prefered by people higher in Openness to experience, a proxy for the strength of exploratory preferences.


In line with the idea that fiction makers target already interesting and prefered stimuli to make their fictions attractive, they also hypothesized that everything that would make the imaginary world more explorable will be selectively retained and cumulatively refined. This explains trends in the cultural evolution of imaginary worlds in fictions, such as the progressive increase of the size of imaginary worlds across time (imaginary worlds embed more and more world data that precisely describle the imaginary environment), or the inclusion of information devices in fictions with imaginary worlds (such as maps, glossaries, family trees or encyclopedias).

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Nicolas Baumard and Edgar Dubourg hypothesized that the appeal for imaginary worlds with extensive non-narrative background information, such as Tolkien’s world Arda or Rowling’s Wizarding World, relies on human exploratory preferences: humans want to explore imaginary worlds for the same reasons, and under the same circumstances, as they are lured by unfamiliar environments in real life.

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Edgar Dubourg, Nicolas Baumard. The Evolutionary Origins of Fiction. Chapter. Handbook of Fiction and Belief. Working Paper.

Edgar Dubourg, Nicolas Baumard. Why and How Did Narrative Fictions Evolve? Fictions as Entertainment Technologies. Frontiers in Psychology. (URL) (PDF)


Edgar Dubourg, Nicolas Baumard. Why Imaginary Worlds? The psychological foundations and cultural evolution of fictions with imaginary worlds. Behavioral and Brain Sciences. Target Article. Forthcoming. (URL) (PDF)