Neural Mechanisms Underlying Human Consensus Decision-Making
Consensus building in a group is a hallmark of animal societies, yet little is known about its underlying computational and neural mechanisms. Here, we applied a computational framework to behavioral and fMRI data from human participants performing a consensus decision-making task with up to five other participants. We found that participants reached consensus decisions through integrating their own preferences with information about the majority group members' prior choices, as well as inferences about how much each option was stuck to by the other people. These distinct decision variables were separately encoded in distinct brain areas—the ventromedial prefrontal cortex, posterior superior temporal sulcus/temporoparietal junction, and intraparietal sulcus—and were integrated in the dorsal anterior cingulate cortex. Our findings provide support for a theoretical account in which collective decisions are made through integrating multiple types of inference about oneself, others, and environments, processed in distinct brain modules.
Additional Information© 2015 Elsevier Inc. Received 3 December 2014, Revised 11 February 2015, Accepted 4 March 2015, Available online 9 April 2015. Published: April 9, 2015. This work was supported by the Grant-in-Aid for JSPS Fellows 232648 (S.S.), the JSPS Postdoctoral Fellowship for Research Abroad (S.S.), the Suntory Foundation Grant-in-Aid for Young Scientists (S.S.), the Nakajima Foundation (R.A.), and the NIMH Caltech Conte Center for the Neurobiology of Social Decision Making (J.P.O.). We thank Tim Armstrong and Lynn K. Paul for support with the participant recruitment, and Ralph E. Lee and Chris Crabbe for assistance with the experiments.
Accepted Version - nihms-671903.pdf
Supplemental Material - mmc1.pdf
Supplemental Material - mmc2.pdf