Imitation, deliberation, and mindreading are characteristically human sociocognitive skills. Research on imitation and its role in social cognition is flourishing across various disciplines. Imitation is surveyed in this target article under headings of behavior, subpersonal mechanisms, and functions of imitation. A model is then advanced within which many of the developments surveyed can be located and explained. The shared circuits model (SCM) explains how imitation, deliberation, and mindreading can be enabled by subpersonal mechanisms of control, mirroring, and simulation. It is cast at a middle, functional level of description, that is, between the level of neural implementation and the level of conscious perceptions and intentional actions. The SCM connects shared informational dynamics for perception and action with shared informational dynamics for self and other, while also showing how the action/perception, self/other, and actual/possible distinctions can be overlaid on these shared informational dynamics. It avoids the common conception of perception and action as separate and peripheral to central cognition. Rather, it contributes to the situated cognition movement by showing how mechanisms for perceiving action can be built on those for active perception.;>;>The SCM is developed heuristically, in five layers that can be combined in various ways to frame specific ontogenetic or phylogenetic hypotheses. The starting point is dynamic online motor control, whereby an organism is closely attuned to its embedding environment through sensorimotor feedback. Onto this are layered functions of prediction and simulation of feedback, mirroring, simulation of mirroring, monitored inhibition of motor output, and monitored simulation of input. Finally, monitored simulation of input specifying possible actions plus inhibited mirroring of such possible actions can generate information about the possible as opposed to actual instrumental actions of others, and the possible causes and effects of such possible actions, thereby enabling strategic social deliberation. Multiple instances of such shared circuits structures could be linked into a network permitting decomposition and recombination of elements, enabling flexible control, imitative learning, understanding of other agents, and instrumental and strategic deliberation. While more advanced forms of social cognition, which require tracking multiple others and their multiple possible actions, may depend on interpretative theorizing or language, the SCM shows how layered mechanisms of control, mirroring, and simulation can enable distinctively human cognitive capacities for imitation, deliberation, and mindreading.

How can “predictive simulation” – as a conscious phenomenon, related to goal imagery – be interchangeable with mirroring, which is an automatic response that, from a first-person perspective, enters awareness only after the act? The correspondence between perception of another's action and execution of one's similar action may be an example of a general perception-motor interface that maps perception onto behaviour or disposition towards action, without the need for simulation.

Susan Hurley's shared circuits model (SCM) rightly begins in action and progresses through a series of layers; but it fails to reach action understanding because it relies on mirroring as a driving force, draws on heavily criticized theories, and neglects the need for shared experience in our grasp of social understanding.

The shared circuits model (SCM) is a bold attempt to explain how humans make sense of action, at different levels. In this commentary we single out five concerns: (1) the lack of a developmental account, (2) the absence of double-dissociation evidence, (3) the neglect of joint attention and joint action, (4) the inability to explain discrete emotion perception, and (5) the lack of predictive power or testability of the model. We conclude that Hurley's model requires further work before it could be seen as an improvement over earlier models.

Differentiating self from other has been investigated at the neural level, and its incorporation into the model proposed Hurley is necessary for the model to be complete. With an emphasis on the feed-forward model in layer 2, we examine the role that self and other disruptions, including auditory verbal hallucinations (AVHs), may have in expanding the model proposed by Hurley.

The target article says surprisingly little about the possible role of shared circuits in language and communication. This commentary considers how they might contribute to linguistic communication, particularly during dialogue. We argue that shared circuits are used to promote alignment between linguistic representations at many levels and to support production-based emulation of linguistic input during comprehension.

Hurley's high level of generality suggests that a control-theoretic framework underpins all of the phenomena in question, but this is problematic. In contrast to the action-perception domain, where the control-theoretic framework certainly applies, there is no evidence that this framework equally applies to feelings and emotions, such as pain, touch, and disgust, where mirroring and simulational mindreading are also found.

The conjunctive conception takes imitation to be a combination of observational learning and copying. In the target article, and elsewhere, this conception generates problems in (1) explaining the copying of intransitive actions, (2) elucidating the potential functions of imitation, and (3) recognising when the correspondence problem has been avoided rather than solved. Hurley's careful use of subpersonal and personal levels of explanation shows us how to tackle these and other questions about imitation.

The shared circuits model (SCM) is a useful explanatory framework that can be applied to interpersonal synchrony by incorporating temporal dynamics. Temporally precise predictive simulations and mirroring enable interpersonal synchrony. When partners' movements are highly synchronous, the self/other distinction can be blurred.

Depth electrode recordings in the human mesial frontal cortex have revealed individual neurons with mirror properties. A third of these cells have excitatory properties during action execution and inhibitory properties during action observation. These cells – which we call super mirror neurons – provide the neural mechanism that implements the functions of layers 3+4 of the shared circuits model (SCM).

The empirical support for the shared circuits model (SCM) is mixed. We review recent results from our own lab and others supporting a central claim of SCM that mirroring occurs at multiple levels of representation. By contrast, the model is silent as to why human infants are capable of showing imitative behaviours mediated by a mirror system. This limitation is a problem with formal models that address neither the neural correlates nor the behavioural evidence directly.

I suggest that layer 4 of the shared circuits model (SCM) should monitor the failure of performing an action, instead of output inhibition, to obtain actual/possible and self/other distinctions. The target article's assumption of selective inhibition leaves some questions unanswered, such as the criteria for the selection. Monitoring failure can answer these questions because failure does not require selection. It also provides a basis for more likely explanation for the phylogenetic and ontogenetic origin of both monitoring and output inhibition.

Through the second year, children's copying behaviour shifts from a focus on emulating to a focus on imitating. This shift can be explained by a change in focus from copying others to satisfy cognitive motivations to copying in order to satisfy social motivations. As elegant and detailed as the shared circuits model (SCM) is, it misses this crucial, motivation-based feature of imitation.

Susan Hurley's impressive article about the shared circuit model (SCM) raises two important issues. First, I suggest that the SCM presupposes relational coding rather than translational coding as neural code. Second, the SCM being the basis for self implies that the self may be characterized as format, relational, and embodied and embedded, rather than by specific and isolated higher-order cognitive contents.

The target article discusses a model of how brain circuits mediate social behaviors such as imitation and mindreading. Hurley suggests potential mechanisms for development of shared circuits. We propose that empirical studies can be designed to differentiate the influence of genetic and learning-based factors on the development of shared circuits. We use the mirror neuron system as a model system.

True to its sensorimotor inspiration, Hurley's shared circuits model (SCM) describes goal-states only within a homeostatic mechanism for action control, neglecting to consider other functions of goals – namely, evaluation and motivation. This restriction thwarts Hurley's project of identifying the information resources enabling social cognition. In order to master intentional behavior, deliberation, and action understanding, we need to be more than just “control freaks.”

The shared circuits model (SCM) relies on well-regarded theories of perception-action, mirror neurons, and forward models, but the functional/informational level of the model limits its ability to explain complex behavior such as true imitation. Data from our lab and others confirm the more general details of the model, accepted by most, but specify the neural mechanisms involved in perception-action processes.

It is argued that the multilayered model offered by the shared circuits model (SCM) falls short of capturing an essential aspect of social cognition, namely, its distributed nature. The SCM therefore falls short of modeling emergent social cognition and behavior.

People cannot understand intentions behind observed actions by direct simulation, because goal inference is highly context dependent. Context dependency is a major source of computational intractability in traditional information-processing models. An embodied embedded view of cognition may be able to overcome this problem, but then the problem needs recognition and explication within the context of the new, layered cognitive architecture.

Three related issues are addressed. First, Hurley treats emulation and imitation as a straightforward dichotomy with emulation emerging first. Recent conceptual analyses and “ghost” chimpanzee experiments challenge this. Second, other recent chimpanzee experiments reveal high-fidelity social transmission, questioning whether copying fidelity is the brake on cumulative culture. Finally, other cognitive processes such as pretence need to be integrated.