Why do we believe in fairies?

This paper examines the cognitive and neurobiological mechanisms underlying the transformation of the fairy figure: from a dangerous entity in medieval folklore to an aestheticized symbol of digital culture. The central research question addresses why the aesthetic appeal of a mythological image increases its subjective plausibility and how this process contributes to the long-term evolution of folkloric representations. Drawing on a narrative review covering three key periods - the medieval era, the Victorian period, and the digital age - the study proposes that this transformation can be explained through the interaction of three mechanisms: an evolutionary mechanism (the Hyperactive Agency Detection Device, HADD), a neuroaesthetic mechanism (activation of reward-related neural systems in response to attractive stimuli), and a psychological mechanism (escapism as a coping strategy). The analysis suggests that in medieval culture, the fairy functioned as a cognitive tool for structuring threat and explaining unpredictable events. During the Victorian era, under the influence of escapism and the commercialization of folklore, the image underwent aestheticization: its miniaturization and increased visual appeal reduced perceived threat. In the digital age, this process has been reinforced through aesthetics such as Cottagecore and Fairycore, where the fairy figure serves a psychological regulatory function in the context of urbanization and information overload. Based on these findings, the paper proposes a preliminary cognitive model of mythological transformation, describing a progression from HADD activation, through the halo effect, to the engagement of dopaminergic reward systems.