How does experience-dependent plasticity contribute to a child’s development of the ability to perceive phonemes during the first year of life?
Infants are born with the ability to categorize speech sounds (Eimas et al. 1971), but these categories are initially universal, not based on the phonemes of a particular language. For instance, Japanese-learning infants can initially discriminate English /r/ and /l/ (Tsushima et al. 1994, as cited in Maye & Gerken, 2000), and English-learning infants can initially discriminate Hindi /t/ and /ţ/ (Werker et al. 1981, as cited in Maye & Gerken, 2000). Over the course of the first year of life, though, the infant gains experience with the native language, and begins to only discriminate contrasts that represent a phonemic distinction in the native language (Werker & Tees 1984, as cited in Maye & Gerken, 2000). Through our research, we would like to understand how these phoneme-related effects on speech perception arise in the language learner (Maye & Gerken, 2000).
According to Goldstein (2014), evidence supporting the idea that the shift in speech perception occurs sometime after 6 months of age is likely to involve experience-dependent plasticity has been provided by Maritza Rivera-Gaxiola and coworkers (2005), who recorded electrical potentials from the surface of the cortex of 7- and 11-month-old American infants from English-speaking households in response to pairs of sounds that sound the same to adult English-speakers but are perceived as different by adult Spanish-speakers. At 7 months of age, the electrical response to these two sounds was different in the English- speaking children, but by 11 months of age, the response had become the same (p.333).
Stay well and God bless.
Linda
References
Goldstein, E. B. (2014). Sensation and perception (9th ed.). Wadsworth.
Maye, J., & Gerken, L. (2000, March). Learning phonemes without minimal pairs. In Proceedings of the 24th annual Boston university conference on language development (Vol. 2, pp. 522-533).
