Understanding others' actions and goals by mirror and mentalizing systems: a meta-analysis

This meta-analysis explores the role of the mirror and mentalizing systems in the understanding of other people's action goals. Based on over 200 fMRI studies, this analysis demonstrates that the mirror system - consisting of the anterior intraparietal sulcus and the premotor cortex - is engaged when one perceives articulated motions of body parts irrespective of their sensory (visual or auditory) or verbal format as well as when the perceiver executes them. This confirms the matching role of the mirror system in understanding biological action. Observation of whole-body motions and gaze engage the posterior superior temporal sulcus and most likely reflects an orientation response in line with the action or attention of the observed actor. In contrast, the mentalizing system - consisting of the temporo-parietal junction, the medial prefrontal cortex and the precuneus - is activated when behavior that enables inferences to be made about goals, beliefs or moral issues is presented in abstract terms (e.g., verbal stories or geometric shapes) and there is no perceivable biological motion of body parts. A striking overlap of brain activity at the temporo-parietal junction between social inferences and other, non-social observations (e.g., Posner's cuing task) suggests that this area computes the orientation or direction of the behavior in order to predict its likely end-state (or goal). No conclusions are drawn about the specific functionality of the precuneus and the medial prefrontal cortex. Because the mirror and mentalizing systems are rarely concurrently active, it appears that neither system subserves the other. Rather, they are complementary. There seems, however, to be a transition from the mirror to the mentalizing system even when body-part motions are observed by perceivers who are consciously deliberating about the goals of others and their behavioral executions, such as when perceived body motions are contextually inconsistent, implausible or pretended.