“…Accordingly, the border between categories is fuzzy (i.e., there are no sharp boundaries that separate members from non-members). Previous research on gratitude (Lambert, Graham & Fincham, 2009), grima (Schweiger Gallo, Fern andez-Dols, Gollwitzer & Keil, 2017), humiliation (Elshout, Nelissen & van Beest, 2017), love (Fehr & Russell, 1991), modesty (Gregg, Hart, Sedikides & Kumashiro, 2008), sadness (Shirai & Nagamine, 2020), shame (Mendoza, Fernandez-Dols, Parrott & Carrera, 2010), vengeance (Elshout, Nelissen & van Beest, 2015), and even the concept of emotion itself (Fehr & Russell, 1984) has shown that a prototype approach allows for identifying the features of emotion concepts (i.e., unique or shared attributes), and thus to delineate their internal structures.…”