a1 School of Psychology & Clinical Language Sciences, University of Reading, UK
a2 School of Psychology, Cardiff University, UK
Two experiments are described which explore the relationship between parental reports of infants' receptive vocabularies at 1 ; 6 () or 1 ; 3, 1 ; 6 and 1 ; 9 () and the comprehension infants demonstrated in a preferential looking task. The instrument used was the Oxford CDI, a British English adaptation of the MacArthur-Bates CDI (Words & Gestures). Infants were shown pairs of images of familiar objects, either both name-known or both name-unknown according to their parent's responses on the CDI. At all ages, and on both name-known and name-unknown trials, preference for the target image increased significantly from baseline when infants heard the target's label. This discrepancy suggests that parental report underestimates infants' word knowledge.
(Received July 24 2006)
(Revised October 31 2006)
c1 Address for correspondence: Dr Carmel Houston-Price, School of Psychology, University of Reading, Earley Gate, Whiteknights, Reading, RG6 6AL, UK. Email: firstname.lastname@example.org. Tel: 0118 378 5378. Fax: 0118 9316715.
[*] The research reported in this article was supported by a project grant from the British Academy (SG-35100). Portions of the data were presented at the conferences of the International Society for Infant Studies (1999) and the Society for Research in Child Development (2005). We would like to express our thanks to the parents and infants who participated in the studies reported and to Graham Schafer, Letitia Naigles and an anonymous reviewer for their comments on a draft of this paper.