Okumura, Y. & Itakura, S.
Kyoto University
Language is one of the most important tools of communication. Recent research shows that social preferences for native language or native-accented speakers emerge remarkably early in development, indicating that infants prefer the speakers in the society to which they belong. The dialect also may be a reliable cue to group membership because it provides information about an individual's social and ethnic group identity. The present study investigated whether infants show social preferences toward native-dialect speakers rather than unfamiliar-dialect ones. Infants at 10 months of age (n = 43) were shown videos in which a native- and an unfamiliar-dialect speaker each talked for 15 seconds. Then, the two speakers offered the infants a toy as real toys appeared in front of them. In addition, we investigated the relationship between infants' social preferences for native-dialect speakers and their own experience with the native dialect by asking the infants' parents how often the infants had been exposed to the dialect. The results demonstrated that the infants preferentially reached for toys that were offered by the speaker who spoke their native dialect (30 of 43 infants, binomial test, two-tailed, p = 0.0137). Moreover, there was a relationship between the proportion of choosing the toy from the native-dialect speaker and the amount of experience infants had with that dialect (r = 0.364, p = 0.016). Therefore, infants showed social preferences for a native-dialect speaker depending on their language experience through daily interactions with the native dialect. These results indicate that native dialects are sufficient to evoke social preferences even in preverbal infants, despite both dialects are within the same native language. Our findings suggest that dialects may be a reliable cue to group membership and infants' orientation toward members of their native community can guide their social and cultural learning.