Casey Lew-Williams

Casey Lew-Williams
Professor, Director of Graduate Studies
216 Peretsman Scully Hall
Ph.D. Stanford University
Curriculum Vitæ (91.12 KB)

Most infants and toddlers have a prodigious ability to learn language, in part because they spend a lot of time listening, looking, and interacting with caregivers. In the Princeton Baby Lab, we study domain-general learning mechanisms and specific features of learning environments in order to understand the beginnings of human cognition and their consequences on children's outcomes.

Each infant's ability to find structure in patterned input is rooted in and shaped by experience. To investigate why experience is important, we manipulate subtle aspects of exposure to language in distilled, 5-minute simulations of learning, and we also define experience in a more ecologically valid way by investigating typicality vs. adversity in developmental circumstances. Using a broad construal of what it means to be in a non-standard language environment, our research includes children learning two languages, children in poverty, children at risk for learning delays/disorders, and adults learning a second language. We combine motivations and methods from the fields of psychology, linguistics, and communication sciences & disorders, and we measure the complexities of eye movements, attention to referents, infant-directed speech, communication with others, and infant-adult neural coupling.

Representative Publications

Nencheva, M. L., Piazza, E. A., & Lew-Williams, C. (in press). The moment-to-moment pitch dynamics of child-directed speech shape toddlers’ attention and learning. Developmental Science.

PDF (2.09 MB)

Piazza, E. A., Hasenfratz, L., Hasson, U., & Lew-Williams, C. (2020). Infant and adult brains are coupled to the dynamics of natural communication. Psychological Science, 31, 6-17.

PDF (1.15 MB)

Schwab, J. F., & Lew-Williams, C. (2020). Discontinuity of reference hinders children’s learning of new words. Child Development, 91, e29-e41.

PDF (815.34 KB)

Piazza, E. A., Iordan, M. C., & Lew-Williams, C. (2017). Mothers consistently alter their unique vocal fingerprints when communicating with infants. Current Biology, 27, 3162-3167.

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Byers-Heinlein, K., Morin-Lessard, E., & Lew-Williams, C. (2017). Bilingual infants control their languages as they listen. Proceedings of the National Academy of Sciences, 114, 9032-9037.

PDF (1.06 MB)