Prototype of Sleepiness

The prototype approach (Shaver et al., 1987) is one of the methods used to clarify the structure of complex psychological concepts such as emotions. This approach assumes that each concept has a prototype, or a most typical example, and identifies it by collecting representative words (attributes) and evaluating their typicality. Words that are highly typical are categorized as central features, and those with low typicality as peripheral features. Previous studies have applied the prototype approach mainly to emotional concepts, but few have focused on sleepiness. Sleepiness refers to a subjective feeling related to the need for sleep and is typically measured using psychological scales such as the Karolinska Sleepiness Scale (KSS; Shahid et al., 2010). Sleepiness is closely associated with affective states such as mood and emotion (Palmer & Alfano, 2017) and is itself an ambiguous concept, which makes it suitable for prototype-based investigation. The purpose of this research project is to clarify the conceptual structure of sleepiness using the prototype approach. Specifically, Study 1 collects descriptive words related to sleepiness using a bottom-up approach, and Study 2 examines the typicality of those words through quantitative evaluations. Additionally, to examine whether typicality judgments differ depending on participants’ sleep-related habits, several sleep-related psychological scales will be measured. This study aims to provide fundamental insights for understanding the core features of sleepiness, contributing to future research on how people perceive and evaluate their own and others’ sleepiness, as well as how beliefs and attitudes toward sleepiness are formed.