This paper provides a partial replication and extension of a classic longitudinal study by Nettelbeck and Wilson [J. Exp. Child Psychol. 40 (1985) 1] that compared the relative influence of maturation and task experience on developmental changes in inspection time (IT). In the study reported in this paper 226 children aged between 6 and 9 were tested on an IT task in Year I and immediately retested to assess the importance of task familiarity. They were also retested I year and 2 years later. Counter to Nettelbeck and Wilson's conclusion, analyses of these data comparing the relative difference made by age maturation and by task experience revealed that task experience has a much bigger effect on children's IT than maturation. The implications of this for wider theoretical interpretations of the relationship between IT and development are discussed. (C) 2001 Elsevier Science Inc. All rights reserved.