Consequences of bilingualism for perceptions of categories and similarity

Speakers of two languages have access to two semantic systems that, while largely similar, may differ in subtle ways. The existence of multiple similar systems offers the potential for comparison of their structures and discovery of the differences between them. We hypothesized that if bilinguals engage in such a comparison process, they may be (a) less likely than monolinguals to view the categories of any single language as natural kinds, and (b) more likely than monolinguals to discern differences among high-similarity items more generally. Monolingual and bilingual participants indicated their level of agreement with statements equating social categories with natural kinds and judged the similarity of pairs of perceptual relations. Compared to monolinguals, bilinguals were less willing to endorse naturalness statements and showed more variability in their similarity judgments. These results suggest that bilingualism may promote sensitivity to differences among highly similar stimuli, linguistic and otherwise.