Classifiers augment and maintain shape-based categorization in Mandarin speakers

Past evidence suggests that adult Mandarin speakers rely on shape more heavily than English speakers when categorizing solid objects (Kuo and Sera 2009). In this experiment, we began to examine that effect developmentally by investigating the acquisition of the three most common Mandarin Chinese classifiers for solid objects (i.e. ge, zhi and tiao) in relation to development in shape-based categorization by native speakers of Mandarin and English from 3 years of age to adulthood. We found that 3-year-old Mandarin speakers were above chance in their classifier knowledge, but this knowledge continued to develop through 7 years of age. We also found that Mandarin speakers relied more heavily on shape than English speakers, and that shape-based categorization among English speakers tended to decline with age on the trials in which shape choices matched the Mandarin classifiers. The findings suggest that classifiers initially augment Mandarin speakers' attention to the shape of solid objects, and then maintain this early stronger shape bias after they are fully learned. The work highlights how categorization and word learning are graded and intertwined.