At the core of Susan Hurley's thesis lies a claim that imitation is an “automatic” process. This idea was famously espoused by William James, who stated that “every representation of a movement awakens in some degree the actual movement which is its object; and awakens it to a maximum degree whenever it is not kept from doing so by an antagonistic representation present simultaneously in the mind” (James Reference James1890, p. 1134). This is referred to as ideomotor theory (Brass & Heyes Reference Brass and Heyes2005) and has been a commonly held position in imitation and mirror neuron research in the last 10 years. Hurley takes a further step to suggest that the evolution of inhibitory processes prevents observed movements from being automatically imitated, and this underlies the capacity for imitation to serve a simulation “theory of mind.”

The notion of automatic imitation seems reasonable at a common-sense level. We often copy others without thinking, perhaps by adopting their posture or facial expressions as we chat with them. But, do we really have an urge to imitate all the actions we observe? And what about those actions that are novel? Is learning by imitation simply a matter of observing action and having these observations “awaken” previously latent action plans already encoded in the observer's brain?

An alternative view is that imitation is an active and intentional process. This was the view taken by the Liepmann (Goldenberg Reference Goldenberg2003), who conducted the first neurological studies of imitation at the beginning of the twentieth century. He saw imitation to be a form of ideomotor praxis, necessitating the implementation of an ideation formed through action observation into an intentional motor act. Studies of action imitation among infants and nonhuman primates would also suggest that imitation is an effortful and selective process (e.g., Gergely et al. Reference Gergely, Bekkering and Király2002; Horner & Whiten Reference Horner and Whiten2005), partly motivated by the promise of reward.

Laboratory evidence for automatic imitation comes from several experiments (Brass et al. Reference Brass, Bekkering, Wohlschlager and Prinz2000; Kilner et al. Reference Kilner, Paulignan and Blakemore2003; Press et al. Reference Press, Bird, Flach and Heyes2005) that show an imitative action response to a cue to be quicker or smoother than when the same response is non-imitative. For example, the cue may consist of an action executed by a mechanical object such as a robot hand. However cue salience may present an intractable problem with these studies (Aicken et al. Reference Aicken, Wilson, Williams and Mon-Williams2007; Jansson et al. Reference Jansson, Wilson, Williams and Mon-Williams2007). Attempts may have been made to control for differences in stimulus salience by matching the visual luminance and size of stimuli, but it remains that a human hand is probably more visually salient than a mechanical hand. Moreover, Gazzola et al. (Reference Gazzola, Aziz-Zadeh and Keysers2006) found that viewing a robotic hand activates the mirror neuron system just as well as a mechanical hand does. This suggests that differences in action responses to robots and humans cannot be explained to be the result of differences in ideomotor compatibility mediated by the mirror neuron system. Brass et al. (Reference Brass, Derrfuss and von Cramon2005) looked at whether inhibition occurs during action observation using functional magnetic resonance imaging (fMRI). Inhibition would predict activity in the rostral anterior cingulate cortex, which monitors conflict and is active during such tasks as the Stroop test (Amodio & Frith Reference Amodio and Frith2006). Brass et al. found activity only in the inferior parietal cortex, reflecting greater differentiation between self and other.

Williams et al. (Reference Williams, Whiten, Waiter, Pechey and Perrett2007) used fMRI to compare brain activity between imitation and a condition where participants were asked to enact a learnt alternative action to the one observed. Even at a liberal threshold, there was no greater activity for the alternative action compared to the imitation condition. This demonstrated no evidence of inhibition. In contrast, there was much greater brain activity during imitation. Clusters of activity were identified in rostral anterior cingulate cortex and lateral orbitofrontal cortex. These findings can be understood in terms of current models of motor control (e.g., Wolpert et al. Reference Wolpert, Ghahramani and Flanagan2001). Imitation is another motor skill which relies on actively developing motor control in an incremental fashion. The effects of any action plan being executed are experienced as consequences for sensory feedback, which serve to modify motor planning functions (cf. the target article). The role of mirror neurons within our model (Williams et al. Reference Williams, Whiten, Waiter, Pechey and Perrett2007) is to respond to the fidelity of the enacted action compared to the perceived action. Error detection results in conflict-related activity in rostral anterior cingulate and a drive to alter behaviour emanating from lateral orbitofrontal cortex. Imitation is therefore an active process of comparison between self and other, requiring continuous modification of action planning with an aim of achieving greater fidelity between self and others. Imitation is intentional, operates within a social context, draws on a capacity for social judgment, and involves new learning.

One form of pathological “automatic” imitation occurs as echopraxia, described in people with autism or frontal lobe lesions (Lhermitte et al. Reference Lhermitte, Pillon and Serdaru1986) or those institutionalized with schizophrenia. Such individuals may have increased suggestibility, and impaired capacity for social judgment and flexible rule learning. Williams et al. (Reference Williams, Whiten and Singh2004) suggested that echopraxia in children may reflect delayed rather than deviant learning of imitation skills, because echopraxia places lower demands on new learning.

Finally, to return to the central theme of Hurley's article, what are the implications of this for the relationship between imitation and mentalizing? The demands placed by self-other matching on new learning may also have a bearing on whether mentalizing processes occur automatically or effortfully. Both imitation and simulation “theory of mind” depend on comparing perceptions of another individual's experience with one's own. Understanding another individual's thoughts or actions often requires new learning and perhaps modifying one's own point of view. Like many other skills that are practiced daily, imitation and mindreading may appear effortless. The evidence and common experience suggests that it is quite often otherwise.