Disruption of the right temporoparietal junction with transcranial magnetic stimulation reduces the role of beliefs in moral judgments
- aDepartment of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139;
- bBerenson–Allen Center for Noninvasive Brain Stimulation, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA 02215; and
- cDepartments of Psychology and Human Evolutionary Biology, Harvard University, Cambridge, MA 02138
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Edited* by Nancy G. Kanwisher, Massachusetts Institute of Technology, Cambridge, MA, and approved February 22, 2010 (received for review December 21, 2009)

Abstract
When we judge an action as morally right or wrong, we rely on our capacity to infer the actor's mental states (e.g., beliefs, intentions). Here, we test the hypothesis that the right temporoparietal junction (RTPJ), an area involved in mental state reasoning, is necessary for making moral judgments. In two experiments, we used transcranial magnetic stimulation (TMS) to disrupt neural activity in the RTPJ transiently before moral judgment (experiment 1, offline stimulation) and during moral judgment (experiment 2, online stimulation). In both experiments, TMS to the RTPJ led participants to rely less on the actor's mental states. A particularly striking effect occurred for attempted harms (e.g., actors who intended but failed to do harm): Relative to TMS to a control site, TMS to the RTPJ caused participants to judge attempted harms as less morally forbidden and more morally permissible. Thus, interfering with activity in the RTPJ disrupts the capacity to use mental states in moral judgment, especially in the case of attempted harms.
Footnotes
- 1To whom correspondence should be addressed. E-mail: lyoung{at}mit.edu.
Author contributions: L.Y., J.A.C., M.H., A.P.-L., and R.S. designed research; L.Y. and J.A.C. performed research; L.Y. and R.S. analyzed data; and L.Y., J.A.C., M.H., A.P.-L., and R.S. wrote the paper.
The authors declare no conflict of interest.
↵*This Direct Submission article had a prearranged editor.
This article contains supporting information online at www.pnas.org/cgi/content/full/0914826107/DCSupplemental.