While we find it plausible that consumption of imaginary worlds satisfies a desire for exploration, we are less convinced that the contemporary surge in the production of such worlds is the outgrowth of an evolutionary-psychological process that has finally been given the proper environment to express itself (target article, sect. 5.3). Instead of relying on such an ultimate-level evolutionary story, we suggest that the popularity of such narratives better tracks something far more proximate, changes in the socioecological environment in which such literature is produced and consumed.

Socioecological psychology seeks to understand human behavior with reference to the social and physical worlds in which people are embedded, investigating how factors such as the built environment, population density, demographic diversity, political system, and economic conditions shape and are shaped by individual and group psychologies (e.g., Choi & Oishi, Reference Choi and Oishi2020; Oishi, Reference Oishi2014). Residential mobility, specifically, may be especially relevant when thinking about the growth of imaginary worlds. As people move from place to place, they gain greater firsthand experience of the potential for difference in the world – different people, different environments, and different ways of being (see e.g., Buttrick & Oishi, Reference Buttrick and Oishi2021). This sense that a world can be other than it currently is would seem to be central to the production and consumption of a robustly imaginary space (e.g., Trilling, Reference Trilling1950).

Empirically, it may be useful to think about the historical context in which these imaginary worlds were and were not created. We can point, for example, to the contemporaneous experiences of Ming China (1368–1664) and Western Europe. Ming China was at least as wealthy as England during the period of Shakespeare and Thomas Moore (Broadberry, Guan, & Li, Reference Broadberry, Guan and Li2018), and had a literary culture producing works as rich and renowned as Journey to the West and The Plum in the Golden Vase. So why was England at the forefront of the development of imaginary worlds, and not China?

One clear difference is that Ming China differed quite significantly from Europe in the degree to which it allowed its population to move. Thanks to the baojia system, most people were tied to their lands and the central government strongly discouraged voluntary residential mobility of any kind, extolling the importance of belonging to a place (Lary, Reference Lary2012). By contrast, contemporary England was hypermobile – from the 1580s to the 1730s, it's estimated that nearly three-quarters of residents, men and women both, left the parish of their birth (Clark & Sounden, Reference Clark and Sounden1988). While England was more mobile than the rest of Western Europe during the seventeenth century (MacFarlane, Reference MacFarlane1991; Moch, Reference Moch2009; Whyte, Reference Whyte2000), Western Europe had largely caught up by the eighteenth century (Hayhoe, Reference Hayhoe2016; see also Rosental, Reference Rosental1999). It may be no surprise then, that the list of imaginary worlds compiled by Wolf (Reference Wolf2012) is so dominated, in the 1600s and 1700s, by French and English writers. As the everyday experiences of people involved changes in place, their appetites for cultural products echoed this variability of location.

Europe was not uniform in its patterns of mobility. Central Europe lagged a bit behind in its rate of residential mobility, and did not reach Western-European rates of mobility until the 1800s (Moch, Reference Moch2009). One estimate has residential mobility rates in Germany roughly quadrupling from 1820 to 1880 (Hochstadt, Reference Hochstadt1999). This timeframe, for example, neatly matches the rise in popularity of the Brothers' Grimm's fairytales – an exemplar of alternate world-building. Initially published in 1812, they were relatively unpopular at first, with their popularity growing through the 1850s, eventually making it into the state curriculum of Prussia in the 1870s (Zipes, Reference Zipes2002), right at the nineteenth century peak of residential mobility; as Germany becomes more mobile, German writers appear with increasing frequency in Wolf's (Reference Wolf2012) list.

Twentieth-century China also helps in thinking about the relationship between socioecology and the consumption of imaginary worlds, thanks to its severe swings in the official permissibility of changing one's residence. Residential mobility had a major peak in the 1920s and 1930s (Lary, Reference Lary2012); with the rise of the Communist government came a return to a place-based system of citizenship, the hukou, which locked roughly 85% of the population in place, and by the 1980s, only 0.6% of this population were “not where they were supposed to be,” that is, had moved from where they had been tied (Chan, Reference Chan, Iredale and Guo2016). The liberalization of the 1980s encouraged ruralites to move: Scholars argue that China is now amongst the most mobile societies in the world, with as many as 200 million migrants (Fan, Reference Fan2008). As the authors point out, science fiction first becomes popular in the late Qing and early-Republican era (mapping on to the first twentieth century wave of residential mobility), and again becomes popular at the turn of the twentieth century, right in the middle of the unprecedented boom in mobility set off by the end of the hukou system in the 1980s.

[We would also note that in their empirical paper (Dubourg, Thouzeau, de Dampierre, & Baumard, Reference Dubourg, Thouzeau, de Dampierre and Baumard2021), the authors find that the share of speculative novels, as a proportion of novels in general, peaks in the 1970s and dips thereafterwards. They may not realize it, but this is a trend that cleanly maps on to the pattern of American residential mobility in the twentieth century (Buttrick & Oishi, Reference Buttrick and Oishi2021), and not the linearly-increasing rise in American GDP (U.S. Bureau of Economic Analysis, 2021).]

In sum then, we argue that there is no need to propose a grand evolutionary theory of the imagined world, when one can point to a perhaps humbler, more parsimonious, hypothesis: that the cultural production of a society is influenced by the ways in which the experiences of everyday people are shaped by the sociological, economic, and demographic features of their worlds (e.g., Marx, Reference Marx and de Leon1852/1998).