Native-language sensitivities: evolution in the first year of life

In the first few months of their lives, human infants can perceive differences in phonetic contrasts not present in their environment and that their parents cannot discriminate. At 12 months, their pattern of discrimination approaches that of their parents. Until recently, it was believed that the perception of native-language categories did not significantly evolve in that period. Kuhl et al. offer compelling new evidence indicating significant increase in native-language perception.