Fig. 2: Evolution of the prevalence of speculative genres and imaginary worlds in literature and cinema.

A Evolution of the relative number of literary works with a speculative genre in the world (N = 50,558 literary works), with a focus on post-1700 literary works. B Evolution of the relative number of movies with a speculative genre in the world (N = 49,566 movies). C Evolution of the relative number of movies that are set in an imaginary world, as assessed by a random forest algorithm (N = 8301 movies). D Sensitivity analysis for the evolution of the relative number of literary works with a speculative genre: the significance of the trend is independent of the cut-off of the minimum number of works per decade (see Methods).