How do statistical learning and perceptual reorganization alter Dutch infant’s perception to lexical tones?

Previous studies show that infants experience perceptual reorganization (PR) in the first year of life, after which their sensitivity towards most non-native speech contrasts greatly decreases. Also, it has been shown that infants can track distributional information from the ambient speech input. Dutch infants of 5-6 and 11-12 months were tested on their perception of a tonal contrast in Mandarin Chinese under uni/bimodal distributions. Results show that statistical learning influences infants’ discrimination of the non-native tonal contrast at 11-12 months, whereas this effect diminishes before the onset of tonal PR at 5-6 months. Two control groups of Dutch infants were tested on their discrimination to the same lexical tonal contrast without statistical exposure. Results showed that only young infants (5-6 months) but not older infants (11-12 months) discriminated the contrast. This not only supports earlier claims that tonal PR occurs at 6-9 months, but also reveals that the effects of PR can be partly reversed by distributional learning as 11-month-old infants’ perception of non-native tones was facilitated in the bimodal condition