We find the argument that our species' enjoyment of other worlds is related to the adaptive value of exploratory behavior to be highly plausible. We suggest that the authors' proposal can be extended by incorporating what has been referred to as the adjacent possible (Kauffman, Reference Kauffman2019; Koppl, Kauffman, Felin, & Longo, Reference Koppl, Kauffman, Felin and Longo2015): the realm of what is just beyond reach. Exploratory behavior enables us to dip into the realm of what is “not quite actual” but rather, the halo of potentiality that is hinted at by what is actual. The appeal of imaginary worlds in the twenty-first century may be related to a radical change in our perception of the adjacent possible, given the rate at which our world has been tamed, mapped out, and homogenized. Compared to our ancestors' world, in which you could hop in a boat and have no idea what sort of exotic land you might encounter, our present world does not hold the same kind of mystery and intrigue. Imaginary worlds provide us with what the physical world offered our ancestors: a sense of potentiality, and a key to the unknown.

Research on concepts, and in particular, quantum models of concept interactions (e.g., Aerts, Aerts, & Gabora, Reference Aerts, Aerts, Gabora, Bruza, Lawless, van Rijsbergen and Sofge2009; Aerts, Broekaert, Gabora, & Sozzo, Reference Aerts, Broekaert, Gabora and Sozzo2016), suggests that this sense of potentiality ultimately stems from how rigidly one's concepts (such as SKY) are tied to specific properties (e.g., “blue”) and contexts (e.g., “Earth”). In quantum models of concepts, the state of full potentiality for a concept is referred to as its ground state, and in a particular context (e.g., the context “Mars”), the concept SKY “collapses” to an actualized state (e.g., the sky of Mars), with context-specific properties (e.g., the sky is red). Exposure to imaginary worlds may decrease mental rigidity by pushing concepts closer to their ground state of full potentiality, thereby enhancing the capacity for creative connections. This hypothesis is consistent with evidence that cognitive flexibility plays an important role in creativity (Dreu, Nijstad, & Baas, Reference Dreu, Nijstad and Baas2011). It is also consistent with studies showing that the creative process is conducive to holding the contents of working memory in a state of potentiality such that ambiguities and inconsistencies are tolerated, and different interpretations or affordances are considered, before gradually settling on a particular solution or outcome (Carbert, Gabora, Schwartz, & Ranjan, Reference Carbert, Gabora, Schwartz, Ranjan, Kozbelt, Locher and Tinio2014; Gabora, Reference Gabora1998; Gabora & Saab, Reference Gabora, Saab, Carlson, Hőlscher and Shipley2011; Scotney, Schwartz, Carbert, Adam Saab, & Gabora, Reference Scotney, Schwartz, Carbert, Adam Saab and Gabora2020).

The authors claim that the existence of imaginary worlds is not explainable in terms of existing theories of cultural evolution. We suggest, however, that they are explainable in terms of the Self-Other Re-organization (SOR) theory of cultural evolution (Gabora, Reference Gabora2019; Smith, Gabora, & Gardner-O'Kearny, Reference Smith, Gabora and Gardner-O'Kearny2018; for mathematical models of SOR, see Gabora & Steel, Reference Gabora and Steel2017, Reference Gabora and Steel2020a, Reference Gabora and Steel2020b, Reference Gabora and Steel2021). SOC postulates that culture evolves, not through a Darwinian process of competitive exclusion and survival of the fittest, but through a largely cooperative process of internal self-maintenance and restructuring within individuals, interleaved with social interaction between individuals. Central to SOR is the notion that cultural outputs are the external evidence of internal change brought about by creativity, which transforms potentialities into actualities by tapping into the adjacent possible. SOR would attribute the existence of imaginary worlds to their capacity to enhance cognitive flexibility and provoke restructuring of one's internal model of the world, or worldview, leading to enhanced capacity to adapt to new circumstances, and thereby, accelerated cultural evolution. Support for this hypothesis comes from evidence that diversifying experiences enhance cognitive flexibility (Ritter et al., Reference Ritter, Damian, Simonton, van Baaren, Strick, Derks and Dijksterhuis2012); imaginary worlds are indeed the ultimate diversifying experience.

The authors' suggestion that imaginary worlds are more popular with individuals who are relatively well-off and enjoy a sense of safety (target article, sect. 4.4.2, para. 2) appears to be inconsistent with the notion of adversity as a form of creative capital, and evidence that agency evolves out of threatening or marginalized conditions (Forgeard, Reference Forgeard2013; Riley & Gabora, Reference Riley, Gabora, Miyake, Peebles and Cooper2012; Weston & Imas, Reference Weston, Imas, Martin and Wilson2018). Indeed, this body of research suggests a hypothesis quite contrary to that of the target paper: that those who are less fortunate may have an even greater appreciation of the sense of escape afforded by imaginary worlds. “Gallows humor,” for example, may be evidence of the creativity-inspiring impact of adversity (Watson, Reference Watson2011). Well-off individuals may simply be more aware of the existence of books and media with imaginary worlds, or more able to afford them, or possess more well-developed reading skills, or more free time.

We suggest that the notion that exploratory behavior in animals is inversely related to fear of predation is only partly true. In a study of exploratory behavior in killifish, although killifish from a high predation lake took longer to explore a new space, they would eventually explore it as thoroughly as killifish from a lake without predation (Gabora & Colgan, Reference Gabora, Colgan, Wilson and Mayer1990). Thus, when space explored was plotted as a function of time, the curve for the killifish populations from the high predation lake was wider and flatter, but the total area under the curves was the same for both populations. This suggests that fear does not affect the magnitude of the drive to explore; it merely tempers it, such that exploration proceeds more cautiously, and takes longer.

We note that imaginary worlds do not appeal to everyone, nor does everyone feel compelled to create them. This is consistent with evidence from an agent-based computational model of cultural evolution which showed that the mean fitness and diversity of the artificial society's outputs was highest when there was a balance between novelty-generating innovators and novelty-preserving imitators (Gabora & Tseng, Reference Gabora and Tseng2017). Innovators may be attracted to imaginary worlds because of their impact on mental flexibility (discussed above), whereas those who favor cultural continuity through the perpetuation of existing methods might tend to view imaginary worlds as merely frivolous.