Exp Brain Res (2011) 211:601–612 DOI 10.1007/s00221-011-2584-4 R E S E A R C H A R T I C L E Social attitudes differentially modulate imitation in adolescents and adults Jennifer Cook • Geoffrey Bird Received: 5 September 2010 / Accepted: 29 January 2011 / Published online: 19 February 2011 The Author(s) 2011. This article is published with open access at Springerlink.com Abstract Previous studies have demonstrated a bidirec- tional relationship between social attitudes and imitation in adults: pro-social attitudes promote imitation, and imitation further increases positive social attitudes. Social attitudes and the social brain are developing throughout the ado- lescent years. Thus, the aim of this study was to test whether pro-social attitudes promote imitation in an Ado- lescent Group to the same extent as in an Adult Group. Participants were primed with pro-social or non-social words in a Scrambled Sentence Priming task. They then completed an Imitation task wherein participants were required to perform a lift action with either the index or middle ﬁnger, whilst observing either a compatible action (e.g. index ﬁnger response and observed index ﬁnger lift) or an incompatible action (e.g. index ﬁnger response and observed middle ﬁnger lift). In an Effector Priming control condition, observed ﬁngers remained stationary but a semi- transparent green mask was added to either the compatible or incompatible ﬁnger. The magnitude of the Imitation Effect and Effector Priming Effect was calculated by subtracting reaction times on compatible trials from those on incompatible trials. In the Adult Group, social priming speciﬁcally modulated the Imitation Effect: pro-social priming produced a larger Imitation Effect but did not modulate the Effector Priming Effect. In adolescents, however, no effect of social priming was seen on either the Imitation or Effector Priming measures. We consider J. Cook G. Bird (&) Institute of Cognitive Neuroscience, University College London, 17 Queen Square, London WC1N 3AR, UK e-mail: g.bird@bbk.ac.uk G. Bird Department of Psychological Sciences, Birkbeck College, Malet Street, London WC1E 7HX, UK possible explanations for these results including the immature development of social brain regions and reduced experience of the relationship between social attitudes and imitation in adolescence. Keywords Imitation Adolescence Priming Chameleon effect Social Introduction Joint action has been deﬁned as a social interaction whereby two or more individuals coordinate their actions in space and time to bring about a change in the environ- ment (Sebanz et al. 2006). One example of this is the ‘Joint Simon’ task in which participants see one of two cues (e.g. red and green squares) appear on either the left or right of a screen and are told that they should respond to a speciﬁc cue (e.g. red square) and that another participant will respond to the other cue. The knowledge that another participant is responding to the redundant cue results in a Simon effect that persists even if the participant cannot see the actions of the other individual. That is, despite not seeing the action of the other participant, there is a sig- niﬁcant effect of spatial compatibility on response time which is normally only seen when the participant must make differential responses to both cues (Sebanz et al. 2003). Another example of joint action is imitation. Imi- tation is a form of joint action in which multiple actors may coordinate their actions in space and time on the basis of the actions they observe. By studying mechanisms of imitation, we can also make progress in understanding the mechanisms underlying other forms of joint action. There is increasing evidence that unconscious imitation promotes positive social attitudes (Chartrand and Bargh 123