PSY 201 Discussion Critical Periods for Language Development
Do you believe there are critical periods for language development? Why or why not? In thinking of about your response, consider at least two of the following: the case study on Genie (the girl isolated from human contact), bilingualism, deaf children who have their hearing restored by cochlear implants, recovery from brain injury to language areas, or other relevant research findings of interest to you.
DQ2 Nativist and Learning Theories
Compare and contrast nativist and learning theories of language development. Which perspective do you think best captures how we develop language?
Children learn language more easily than adults, though when and why this ability declines have been obscure for both empirical reasons (underpowered studies) and conceptual reasons (measuring the ultimate attainment of learners who started at different ages cannot by itself reveal changes in underlying learning ability). We address both limitations with a dataset of unprecedented size (669,498 native and non-native English speakers) and a computational model that estimates the trajectory of underlying learning ability by disentangling current age, age at first exposure, and years of experience. This allows us to provide the first direct estimate of how grammar-learning ability changes with age, finding that it is preserved almost to the crux of adulthood (17.4 years old) and then declines steadily. This finding held not only for “difficult” syntactic phenomena but also for “easy” syntactic phenomena that are normally mastered early in acquisition. The results support the existence of a sharply-defined critical period for language acquisition, but the age of offset is much later than previously speculated. The size of the dataset also provides novel insight into several other outstanding questions in language acquisition.
People who learned a second language in childhood are difficult to distinguish from native speakers, whereas those who began in adulthood are often saddled with an accent and conspicuous grammatical errors. This fact has influenced many areas of science, including theories about the plasticity of the young brain, the role of neural maturation in learning, and the modularity of linguistic abilities (Johnson & Newport, 1989; Lenneberg, 1967; Morgan-Short & Ullman, 2012; Newport, 1988; Pinker, 1994). It has also affected policy, driving debates about early childhood stimulation, bilingual education, and foreign language instruction (Bruer, 1999).
However, neither the nature nor the causes of this “critical period” for second language acquisition are well understood. (Here, we use the term “critical period” as a theory-neutral descriptor of diminished achievement by adult learners, whatever its cause.) There is little consensus as to whether children’s advantage comes from superior neural plasticity, an earlier start that gives them additional years of learning, limitations in cognitive processing that prevent them from being distracted by irrelevant information, a lack of interference from a well-learned first language, a greater willingness to experiment and make errors, a greater desire to conform to their peers, or a greater likelihood of learning through immersion in a community of native speakers