Why GRUE? An Interpoint-Distance Model Analysis of Composite Color Categories

This article applies the interpoint-distance model (IDM) to explain composite color categories that continue to challenge existing models in the literature. Using universal cognitive principles and heuristics suggested in the IDM, analyses demonstrate that the composite category blue-green (or GRUE) seen in many languages is one of several natural coding configurations expected in the development of a color lexicon for communicating about color sensations within a given ethnolinguistic society. Using the IDM, these enigmatic composite color categories can be explained and integrated into an updated view of the psychological processing responsible for similarities in cross-cultural color processing. The IDM also allows for revision of existing theories and increases our understanding of the cognition that underlies individuals' color naming, categorization, and concept formation.