An experiment with the sequential touching technique investigated the role of object parts on 1- to 2-year-old infants’ ability to form basic-level categories (cows and cars) from two different superordinate domains. Using the novel task design developed by Rakison and Butterworth, infants were tested with normal category exemplars as well as modified versions that were made by removing or attaching object parts (legs and wheels). Results revealed a developmental trend whereby infants’ use of object parts in categorization decreased with age. Analyses of infants’ functional responses (e.g. jumping or rolling) suggested that they might initially associate different kinds of object movement with different kinds of parts.