Department of Psychology



Peter de Villiers is pursuing four ongoing research projects:

1) On the role of language acquisition and executive function development in theory of mind understanding (an important component of children’s social-cognitive development). In collaboration with his wife Jill and several Smith College undergraduates he has been investigating these issues in typically developing preschoolers, in children with specific language impairment (SLI), and in oral and signing deaf children. The research is supported by a grant from the US National Institutes of Health.

2) On ways to assess the pragmatic language skills of typically-developing and language- and communication-impaired children. Peter developed the pragmatics domain subtests for the Diagnostic Evaluation of Language Variation (DELV-NR) (Seymour, Roeper, & de Villiers, 2005), a comprehensive language evaluation designed to provide an unbiased assessment of children who are speakers of dialects of English such as African-American English (AAE). That test was published by The Psychological Corporation and Peter and Jill are now working on a full standardized test of 3 to 12 year old children’s pragmatic use of their language.

3) On the acquisition of one of the nine national languages of South Africa, isiXhosa. Xhosa is a Southern Bantu language of the Nguni group (together with Zulu), spoken by approximately 25% of South Africa’s 42 million people. Xhosa has special linguistic properties that make it fascinating to linguists and potentially able to illuminate several theoretical questions in the field of first language acquisition. Peter and Jill are working with Sandile Gxilishe, Associate Professor of African languages at the University of Cape Town, to analyze longitudinal samples of the spontaneous speech of young children acquiring Xhosa as their first language. The project arose out of a grant from the Mellon Foundation to Smith College to develop collaborative projects between Smith faculty and faculty at UCT.

4) On the relationship between deaf children’s “through-the-air” language (in English or ASL) and their literacy development. Working closely with teachers at Clarke School for the Deaf in Northampton and the Rhode Island School for the Deaf in Providence, he helped develop both a Language Arts Curriculum and a hands-on Science Curriculum for deaf students. The work was funded by grants from the Kellogg Foundation, the UPS Foundations and the Pew Charitable Trusts.

Peter de Villiers


Curriculum Vitae


Lab Members