Anim Cogn (2005) 8: 31–36 DOI 10.1007/s10071-004-0232-0 ORIGINAL ARTICLE Mark Nielsen . Emma Collier-Baker . Joanne M. Davis . Thomas Suddendorf Imitation recognition in a captive chimpanzee (Pan troglodytes) Received: 9 March 2004 / Revised: 18 June 2004 / Accepted: 22 July 2004 / Published online: 21 August 2004 # Springer-Verlag 2004 Abstract This study investigated the ability of a captive chimpanzee (Pan troglodytes) to recognise when he is being imitated. In the experimental condition of test 1a, an experimenter imitated the postures and behaviours of the chimpanzee as they were being displayed. In three control conditions the same experimenter exhibited (1) actions that were contingent on, but different from, the actions of the chimpanzee, (2) actions that were not contingent on, and different from, the actions of the chimpanzee, or (3) no action at all. The chimpanzee showed more “testing” sequences (i.e., systematically varying his actions while oriented to the imitating experimenter) and more repetitive behaviour when he was being imitated, than when he was not. This finding was replicated 4 months later in test 1b. When the experimenter repeated the same actions she displayed in the experimental condition of test 1a back to the chimpanzee in test 2, these actions now did not elicit those same testing sequences or repetitive behaviours. However, a live imitation condition did. Together these results provide the first evidence of imitation recognition in a nonhuman animal. Keywords Chimpanzee . Imitation . Imitation recognition Introduction Over the last decade, similarities and differences have been established in the way human children and chimpanzees engage in imitation (e.g., Carpenter et al. 1995; Nagell et al. 1993; Tomasello et al. 1993; Whiten et al. 1996). In this paper, we use the term “imitation” to refer very broadly to instances where individuals repro- duce actions or behaviours they have witnessed being produced by another (i.e., copying). Developmental psychologists have also begun to study the ability of human children to recognise when they themselves are being imitated by others, and this ability, along with the ability to imitate, has become recognised as an important aspect of early social communication (Asendorpf et al. 1996; Meltzoff 1990; Meltzoff and Decety 2003; Nadel 2002; Nielsen and Dissanayake 2004). In contrast, despite a large literature on imitation in chimpanzees, there are no experiments investigating imitation recognition (Sudden- dorf and Whiten 2001). This is the subject of the present study. In response to being imitated, infants in their second year tend to repeat the particular gesture that is being imitated and engage in “testing” behaviour (i.e., system- atically varying activity while closely watching the imitating adult 1 ) to see if their behaviour will continue to be copied (Meltzoff 1990; Meltzoff and Decety 2003). Asendorpf et al. (1996) studied imitation recognition in 18-month-old infants by having a sole adult closely imitate all of an infant’ s activities and postures while sitting opposite him or her. In response to being imitated in this way, over half (57%) of the 76 infants in this study showed the kind of “testing” behaviour that the authors interpret as evidence for imitation recognition (Asendorpf et al. 1996; Meltzoff and Decety 2003). We adopted this paradigm to investigate whether a chimpanzee would behave similarly when he was being imitated. Methods Subject and housing conditions The subject in this study was a male captive-born chimpanzee (Pan troglodytes), Cassie, aged 31 years. Cassie is housed with his 27-year-old half-brother, Ockie, M. Nielsen (*) . E. Collier-Baker . J. M. Davis . T. Suddendorf Early Cognitive Development Unit, School of Psychology, University of Queensland, Brisbane, QLD, 4072, Australia e-mail: nielsen@psy.uq.edu.au Tel.: +61-7-33469643 Fax: +61-7-33654466 1 A humorous example of the Marx Brothers showing this type of behaviour can be viewed at: http://xroads.virginia.edu/~MA01/ Cober/marx/mirrormovie.html.