Universals and Variation in Language and Thought: Concepts, Communication, and Semantic Structure.

다국어 초록 (Multilingual Abstract)

Why do languages parcel human experience into categories in the ways they do, and to what extent do these categories in language shape our view of the world? Both language and nonlinguistic cognition vary across cultures, but not arbitrarily, suggesting that there may be universal constraints on how we talk and think. This dissertation explores the sources and consequences of universals and variation in language and thought in four parts.
The first study examines a major premise of the universalist view of cognition, that speakers of all languages share a universal conceptual space, which is partitioned by the categories in language. Previous research on color cognition supports this view; when English speakers successively pile-sort colors, their sorting recapitulates an independently proposed hierarchy of color semantics across languages (Boster, 1986). Here I extend that finding to the domain of spatial relations. Levinson et al. (2003) have proposed a hierarchy of spatial category differentiation, and I show that English speakers successively pile-sort spatial scenes in a manner that recapitulates that semantic hierarchy. This finding provides evidence for a specific hierarchy of spatial notions as a model of universals in conceptual structure, and suggests that universal patterns observed across languages reflect general cognitive forces that are available in the minds of speakers of a single language.
The second project of this dissertation demonstrates a process by which domain-specific conceptual universals and more general communicative pressures may shape categories in language, extending a previous account (Regier et al., 2015) of semantic universals and variation. In particular, I show that human simulation of cultural transmission in the lab produces systems of semantic categories that converge toward greater informativeness, in the domains of color and spatial relations. These findings suggest that larger-scale cultural transmission over historical time could have produced the diverse yet informative category systems found in the world's languages. This work supports the communicative efficiency account of semantic universals and variation and establishes a process through which categories in language become increasingly efficient and increasingly universal.
The third study extends the previous account of categories in language to cognition more broadly, showing that the same principles that govern efficient semantic systems also characterize nonlinguistic cognition. I provide an account of spatial cognition in which conceptual categories optimize the trade-off between informativeness (making for fine-grained and intuitively organized spatial categories) and simplicity (limiting the number of categories). I find that pile sorts made by speakers of diverse languages match this universal account more closely than they match the semantics of the sorter's native language. These results suggest that across languages, spatial cognition reflects universal pressures for efficient categorization, and observed universals in category structure and granularity result from these pressures.
The final project of this dissertation probes the role of language in online spatial reasoning, using linguistic interference to prevent participants from relying on language in solving a spatial task. In previous work, adult English speakers have been shown to use a spatial frame of reference that differs from that of nonhuman primates and toddlers (Haun et al., 2006), suggesting that learning the spatial frame of reference used in English may motivate a switch away from universal modes of spatial thought. I find that under linguistic interference, despite a sharp increase in error, adult English speakers fail to readopt the spatial frame of reference used by nonhuman primates and toddlers. This finding rules out the possibility that language affects spatial frames of reference online and accordingly argues against Kay and Kempton's (1984) account, which predicts a removable online role of language. This result raises the stakes of the debate over the role of language in nonlinguistic spatial frames of reference---either something other than language causes alignment between linguistic and nonlinguistic frames of reference, or language learning fundamentally restructures nonlinguistic spatial cognition in a way that is difficult to reverse.
The findings of this dissertation in the domain of space, taken together with parallels in other cognitive domains, reinforce an emerging consensus on the relation of language and thought, by which all people share a universal conceptual foundation that may be altered by language. The research here further elaborates this account, suggesting that universals and variation in both language and thought may derive to some extent from general principles of efficiency. At the same time, it challenges the generality of a classic formulation of this view (Kay & Kempton, 1984), motivating future research. In both complementing and challenging an emerging consensus on language and thought, this dissertation informs our view of language, a defining feature of human cognition, and contributes to a more complete understanding of the nature of thought.