Abstract

In our daily life, we continuously monitor others' behaviors and interpret them in terms of goals, intentions, and reasons. Despite their central importance for predicting and interpreting each other's actions, the functional mechanisms and neural circuits involved in action understanding remain highly controversial [1Csibra G. Action mirroring and action interpretation: An alternative account.in: Haggard P. Rosetti Y. Kawato M. Sensorimotor Foundations of Higher Cognition. Attention and Performance XXII. Oxford University Press, Oxford2007: 435-480Google Scholar, 2Saxe R. Against simulation: The argument from error.Trends Cogn. Sci. 2005; 9: 174-179Abstract Full Text Full Text PDF PubMed Scopus (215) Google Scholar]. Two alternative accounts have been advanced. Simulation theory [3Gallese V. Goldman A. Mirror neurons and the simulation theory of mind-reading.Trends Cogn. Sci. 1998; 2: 493-501Abstract Full Text Full Text PDF PubMed Scopus (1906) Google Scholar] assumes that we understand actions by simulating the observed behavior through a direct matching process that activates the mirror-neuron circuit [4Rizzolatti G. Craighero L. The mirror-neuron system.Annu. Rev. Neurosci. 2004; 27: 169-192Crossref PubMed Scopus (5078) Google Scholar]. The alternative interpretive account [5Gergely G. Csibra G. Teleological reasoning in infancy: The naive theory of rational action.Trends Cogn. Sci. 2003; 7: 287-292Abstract Full Text Full Text PDF PubMed Scopus (604) Google Scholar] assumes that action understanding is based on specialized inferential processes activating brain areas with no mirror properties [1Csibra G. Action mirroring and action interpretation: An alternative account.in: Haggard P. Rosetti Y. Kawato M. Sensorimotor Foundations of Higher Cognition. Attention and Performance XXII. Oxford University Press, Oxford2007: 435-480Google Scholar]. Although both approaches recognize the central role of contextual information in specifying action intentions, their respective accounts of this process differ in significant respects [1Csibra G. Action mirroring and action interpretation: An alternative account.in: Haggard P. Rosetti Y. Kawato M. Sensorimotor Foundations of Higher Cognition. Attention and Performance XXII. Oxford University Press, Oxford2007: 435-480Google Scholar, 5Gergely G. Csibra G. Teleological reasoning in infancy: The naive theory of rational action.Trends Cogn. Sci. 2003; 7: 287-292Abstract Full Text Full Text PDF PubMed Scopus (604) Google Scholar, 6Iacoboni M. Molnar-Szakacs I. Gallese V. Buccino G. Mazziotta J.C. Rizzolatti G. Grasping the intentions of others with one's own mirror neuron system.PLoS Biol. 2005; 3: e79Crossref PubMed Scopus (1329) Google Scholar, 7Fogassi L. Ferrari P.F. Gesierich B. Rozzi S. Chersi F. Rizzolatti G. Parietal lobe: From action organization to intention understanding.Science. 2005; 308: 662-667Crossref PubMed Scopus (1363) Google Scholar]. Here, we investigated the role of context in action understanding by using functional brain imaging while participants observed an unusual action in implausible versus plausible contexts. We show that brain areas that are part of a network involved in inferential interpretive processes of rationalization and mentalization but that lack mirror properties are more active when the action occurs in an implausible context. However, no differential activation was found in the mirror network. Our findings support the assumption that action understanding in novel situations is primarily mediated by an inferential interpretive system rather than the mirror system.