The mirror matching system: A shared manifold for intersubjectivity

Empathy is the phenomenal experience of mirroring ourselves into others. It can be explained in terms of simulations of actions, sensations, and emotions which constitute a shared manifold for intersubjectivity. Simulation, in turn, can be sustained at the subpersonal level by a series of neural mirror matching systems. The article by Preston & de Waal (Pd see Gallese 2000a; 2000b; 2001; see also Rizzolatti et al. 2001), emotion perception (as simulation of the perceived emotion; see Adolphs 1999; Adolphs et al. 2000; Commentary/Preston & deWaal: Empathy: Its ultimate and proximate bases BEHAVIORAL AND BRAIN SCIENCES (2002) 25:1 35 Figure 1 (Eslinger et al.). Results of fMRI study of normal volunteers making explicit moral judgments, showing activation primarily of frontopolar cortex, medial frontal gyrus and related regions Gallese 2001), and mindreading. Simulation theory in fact holds that we understand others’ thoughts by pretending to be in their “mental shoes,” and by using our own mind/body as a model for the minds of others (Gallese & Goldman 1998; Goldman 1989; Gordon 1986; Harris 1989). Is there a further level of description that can provide a common and coherent explanatory frame for all these different simulation mechanisms? We propose, yes: such a level could be represented by the neural matching system constituted by mirror neurons (Gallese et al. 1996; 2002; Rizzolatti et al. 1996; Umilta et al. 2001; see also Rizzolatti et al. 2001) – or by equivalent neural systems described in the human brain (Fadiga et al. 1995; Iacoboni et al. 1999; Nishitani & Hari 2000). Mirror neurons could underpin a direct, automatic, nonpredicative, and noninferential simulation mechanism, by means of which the observer would be able to recognize, understand, and imitate the behavior of others. The authors maintain that “mirror neurons . provide concrete cellular evidence for the shared representations of perception and action” (see target article, sect. 3.1). They fail, nevertheless, to draw the correct conclusions from such a statement. It is true, as they argue, that mirror neurons do not produce per se any empathy. However, if an action-perception matching is crucial for the production of empathy, as the authors suggest, mirror neurons represent the most parsimonious neural system so far described, enabling such a matching to occur. The trick here is not to confound the phenomenal aspect of behavior, its functional level of description, and the neural mechanism at its base. Preliminary results suggest that a mirror matching system could be at the basis of our capacity to perceive in a meaningful way, not only the actions, but also the sensations and the emotions of others (see Gallese 2001). Single neuron recording experiments in humans have demonstrated that the same neurons become active when the subject either feels pain or observes others feeling pain (Hutchison et al. 1999). Furthermore, a recent fMRI study has shown that the amygdala becomes active not only during the observation, but also during the active expression of facial emotions, especially when imitation is involved (Carr et al. 2001). In conclusion, these recent findings suggest that a neural matching system is present also in a variety of apparently nonmotor-related human brain structures. Thus, different simulation mechanisms are applied in different domains, being sustained by a mirror-matching, dual-mode of operation (action-driven and perception-driven) of given brain structures. We propose that such simulation mechanisms may constitute altogether a shared manifold of intersubjectivity (see Gallese 2001).