J. Experimental Child Psychology 88 (2004) 297–318 www.elsevier.com/locate/jecp 0022-0965/$ - see front matter  2004 Elsevier Inc. All rights reserved. doi:10.1016/j.jecp.2004.04.004 Generalization of deferred imitation during the Wrst year of life Amy E. Learmonth, ¤ Rebecca Lamberth, and Carolyn Rovee-Collier ¤ Department of Psychology, Rutgers University, Piscataway, NJ 08854, USA Received 28 October 2003; revised 22 April 2004 Abstract Infants Wrst generalize across contexts and cues at 3 months of age in operant tasks but not until 12 months of age in imitation tasks. Three experiments using an imitation task examined whether infants younger than 12 months of age might generalize imitation if conditions were more like those in operant studies. Infants sat on a distinctive mat in a room in their home (the context) while an adult modeled actions on a hand puppet (the cue). When they were tested 24 h later, 6-month-olds generalized imitation when either the mat or the room (but not both) diVered, whereas 9-month-olds generalized when both the mat and the room diVered. In addi- tion, 9-month-olds who imitated immediately also generalized to a novel test cue, whereas 6- month-olds did not. These results parallel results from operant studies and reveal that the similarity between the conditions of encoding and retrieval—not the type of task—determines whether infants generalize. The Wndings oVer further evidence that memory development dur- ing infancy is a continuous function.  2004 Elsevier Inc. All rights reserved. Keywords: Generalization; Deferred imitation; Context; Acquired equivalence; Infant memory ¤ Corresponding authors. Fax: 1-732-445-2263. E-mail addresses: amyel@rci.rutgers.edu (A.E. Learmonth), rovee@rci.rutgers.edu (C. Rovee-Collier).