I summarize our hypothesis published in a recent Behavioral and Brain Sciences Target Article.
Game of Thrones, Lord of the Ring, Harry Potter, Star Wars, Zelda, Avatar… Fictions set in large and rich imaginary worlds are more and more popular around the world. Why do humans tend to enjoy fictional environments that differ from the real world?
More mysteries… First, there is variability in this widespread cultural preference: some people hate imaginary worlds. Why doesn’t everybody enjoy them? Second, imaginary worlds could have been invented way earlier in history. Why is it a recent cultural phenomenon?
Our hypothesis is straightforward: humans minds find imaginary worlds interesting because they evolved a cognitive adaptation the function of which is to prompt exploration. Basically, humans, just like other animals, are curious: they detect and seek new information.
This is what Tolkien thought, when he wrote "Part of the attraction of The Lord of the Rings relies on the intrinsic feeling of reward we experience when viewing far off an unvisited island or the towers of a distant city". But also ShigeruMlyamoto, the creator of Zelda who stated that he "wanted to create a game world that conveyed the same feeling you get when you are exploring a new city for the first time".
First, we focus on this hypothesis and its implications at the ultimate level: the explanatory level that focus on the challenges in ancestral environments that served as selection pressures for cognitive and behavioral traits. This strategy of seeking new information evolved through natural selection, even before the divergence of humans, because it brought benefits to those curious organisms who therefore survived longer, reproduced more, and spread their genes in the population. It is an adaptive response to the evolutionary challenge of uncertainty: in an uncertain world, organisms who try to make their ecology more predictable fare better. This is why animals are curious too (e.g., they look longer at unfamiliar objects).
There is evidence from studies in environmental aesthetics that, on average, humans rate higher images that prompt exploration. What makes a setting appealing is the promise of novel information, inferred from cues indicating that an enrichment in knowledge is possible.
In humans, the dopamine system reacts specifically to novel stimuli even if they do not involve primary reward. For instance, data from experiments with injections of a selective dopamine transporter inhibitor show that dopamine crucially enhances novelty-related value.
But such exploratory preferences vary. Behavioral ecologists and evolutionary biologists predict that organisms shouldn’t explore at the same rate in secure and affluent ecologies versus in dangerous and harsh ecologies. It is the effect of phenotypic plasticity.
At the ultimate level, cognitive and spatial exploration is a kind of long-term investment: you incur costs now, hoping to discover information that will be beneficial in the future. This strategy is costlier in harsh environments, because:
(1) it is risky: one may not find any valuable information or innovative ideas, and come back empty handed (which is costlier with no secure amount of resources to begin with);
(2) it is time- and energy-consuming, and therefore represents big opportunity costs: in harsh environments one is better off spending time and energy in more pressing needs;
(3) it is a future-oriented strategy: one shouldn’t invest in information valuable only in the long-term in a dangerous environment.
To sum up, exploration is a better strategy in conditions of relative safety. Importantly, its means that organisms living in scarcity explore less because exploitative strategies are better adapted to that type of environment.
For instance, in different parrot species, the presence of habitat, fruits and buds accelerates the timing of first contact after the introduction of a novel object. In spatial uncertainty experiment, fed honeybees explore more than starved ones. Closer to humans: the longer time orangutans have spent protected and fed by humans, the more curious they are. In humans: across time, more affluent societies explore more scientifically. Today, population levels of openness to change and novelty are correlated to GDP per capita. Humans explore more in periods of prosperity (in diachrony) and in affluent countries (in synchrony).
Of course variation in curiosity is not fully explained by ecological variation. Curiosity also varies with age. Typically, organisms go through an early period of exploration followed by a later period of exploitation (a developmental division of labor). More precisely, exploratory preferences increase continuously until adolescence and start to decrease then. In the Hadza, a group of Tanzanian hunter-gatherers, and data collected with GPS devices, this life-history pattern is observable with two measures: distance and number of steps.
There is a wealth of experimental evidence showing that children spend more time and energy exploring multiple options than adults do in exploration-exploitation tasks, but also in many other experimental tasks such as the bandit task or problem-solving tasks. It is consistent with how exploration varies with security and affluence: in childhood up until adolescence, humans are usually protected and fed by their parents through resource transfers, and this is the case in hunter-gatherers (see bold line).
Such interindividual differences in curiosity and exploration are captured by the personality trait Openness, which also seem to follow the same evolution across age and the same variation according to socio-economic status.
Coming back to the cultural domain and our main hypothesis, we therefore predicted that: people (1) higher in Openness, (2) younger, and (3) living in more affluent and secure contexts should enjoy more fictions with imaginary worlds.
Correlational models with both experimental and observational data support such predictions (these preliminary results are part of a forthcoming empirical article).
This theory could therefore explain why imaginary worlds emerged recently in history. A large enough number of potential consumers had to be better-off, and therefore curious enough, for such fictions to be interesting and appealing to a broad audience. To sum up, the exploration hypothesis posits that imaginary worlds fall into the actual domain of human curiosity: people are interested to them in the extent to which they are curious about the real world, and under the same circumstances. In the paper, we develop further this exploration hypothesis, its implications on culture, and we derive more predictions, for instance about the exaggeration of cultural content (the stimulus-intensification hypothesis).