606 were informed that they would be asked to take part in two separate experiments, one on the effect of colour on word processing and the other on responses to numbers. Prior to testing all participants were read standardized instructions and completed 5 example trials of the Scrambled Sentence Priming task. Participants were shown an example of each trial type from the Imitation and Effector Priming Control Tasks. All participants were also presented with a written version of the instructions. For both the pro- and non-social priming tasks, participants were told that they would see ﬁve words on the screen and that they should use four of the ﬁve words to make a grammatically correct sentence. The subjects were instructed to select the words by clicking on each one with the computer mouse. They were told that once they had clicked on the fourth and ﬁnal word in their created sentence, a new screen would appear with ﬁve different words. For the Imitation and Effector Priming Control tasks, participants were told to place the index ﬁnger of their right hand on the letter ‘V’ on the computer keyboard and the middle ﬁnger of their right hand on the letter ‘B’ on the keyboard. Participants were told to lift their index ﬁnger if a number 1 appeared on the screen and lift their middle ﬁnger if a number 2 appeared on the screen. Before the Imitation and Effector Priming Control tasks commenced, participants conducted a training ses- sion. The training programme required participants to make 5 correct consecutive responses in order for them to continue onto the experimental version of the task. The probability of making 5 correct consecutive responses by chance is \0.05; therefore, the training task ensured that participants could perform the task before data collection began. Following the Imitation and Effector Priming Control tasks, participants were asked to complete a debrieﬁng questionnaire designed to ascertain whether participants had guessed the purpose of the experiment (see Leighton et al. 2010). This questionnaire included the following questions: ‘‘What do you think the purpose of this exper- iment was? What do you think this experiment was trying to study? Did you think that any of the tasks were related in any way? If yes, in what way? Did anything you did on one task affect anything you did in another task? If yes, then how did it affect you? When you were arranging the words, did you notice anything unusual about the words? Did you notice a pattern or theme to the words? Did you have a particular goal or strategy when arranging the words?’’ Data analysis Priming task 123 For all participants, all of the sentences produced in the Priming task were scored. A grammatically incorrect Exp Brain Res (2011) 211:601–612 sentence yielded an error score of 1. Error scores for all 32 sentences were then summed to give an error score across all sentences. Imitation and effector priming control tasks For the Imitation and Effector Priming Control tasks, error- trials in which the participant lifted the incorrect ﬁnger were removed from the analysis. RTs were ﬁltered such that those less than 150 ms were excluded under the assumption that they were expectancy errors and those longer that 2,000 ms were excluded under the assumption that they reﬂected a lapse in attention. Results All results are reported using an a of P \ 0.05. Two-tailed tests are used except where a directional prediction has been made on the basis of pre-existing literature. When a one-tailed test has been used, this is indicated following a statistically signiﬁcant result. Examination of the debrieﬁng questionnaire data indi- cated that no participant correctly guessed the purpose of either the Priming or Imitation and Effector Priming Control tasks. Furthermore, no participant correctly iden- tiﬁed a link between the studies or a theme among the words presented in the Priming task. Therefore, we can conclude that no participant was aware of the type of priming they had received or that the purpose of the study was to examine imitation and its relationship with social attitudes. Priming task In the Priming task, no group made more than 2 errors on average (Adolescent Non-social mean = 1.41; Adolescent Pro-social mean = 1.59; Adult Non-social mean = 1.39; Adult Pro-social mean = 0.93). To test whether either Age or Prime Group signiﬁcantly affected the number of errors, we employed a 2 9 2 ANOVA with between-subjects factors Age Group and Prime Group. There was no sig- niﬁcant interaction between Age and Prime Group (F(1,86) = 0.63, P = 0.43) and no main effect of Age Group (F(1,86) = 0.71, P = 0.40) or Prime Group (F(1,86) = 0.13, P = 0.72). To be sure that no one group produced more errors for the sentences which contained prime words, we created a ‘priming sentence error score’ by summing errors for the 24 sentences which contained a priming word. No group made more than 2 errors on average (Adolescent Non-social mean = 1.12; Adolescent Pro-social mean = 1.06; Adult Non-social mean = 1.07; Adult Pro-social mean = 0.68). To test whether Age or