Behavioral contagion during learning about another agent's risk-preferences acts on the neural representation of decision-risk
Our attitude toward risk plays a crucial role in influencing our everyday decision-making. Despite its importance, little is known about how human risk-preference can be modulated by observing risky behavior in other agents at either the behavioral or the neural level. Using fMRI combined with computational modeling of behavioral data, we show that human risk-preference can be systematically altered by the act of observing and learning from others' risk-related decisions. The contagion is driven specifically by brain regions involved in the assessment of risk: the behavioral shift is implemented via a neural representation of risk in the caudate nucleus, whereas the representations of other decision-related variables such as expected value are not affected. Furthermore, we uncover neural computations underlying learning about others' risk-preferences and describe how these signals interact with the neural representation of risk in the caudate. Updating of the belief about others' preferences is associated with neural activity in the dorsolateral prefrontal cortex (dlPFC). Functional coupling between the dlPFC and the caudate correlates with the degree of susceptibility to the contagion effect, suggesting that a frontal–subcortical loop, the so-called dorsolateral prefrontal–striatal circuit, underlies the modulation of risk-preference. Taken together, these findings provide a mechanistic account for how observation of others' risky behavior can modulate an individual's own risk-preference.
Additional Information© 2016 National Academy of Sciences. Edited by Ranulfo Romo, Universidad Nacional Autonóma de México, Mexico City, Distrito Federal, Mexico, and approved February 23, 2016 (received for review January 7, 2016). Published online before print March 21, 2016. We thank Simon Dunne and Keise Izuma for helpful comments on the manuscript. This work was supported by the Japan Society for the Promotion of Science (JSPS) Postdoctoral Fellowship for Research Abroad (S.S.) and the National Institute of Mental Health (NIMH) Caltech Conte Center for the Neurobiology of Social Decision Making (J.P.O.). Author contributions: S.S., E.L.S.J., P.B., and J.P.O. designed research; S.S. and E.L.S.J. performed research; S.S., E.L.S.J., and J.P.O. analyzed data; and S.S., P.B., and J.P.O. wrote the paper. The authors declare no conflict of interest. This article is a PNAS Direct Submission. This article contains supporting information online at www.pnas.org/lookup/suppl/doi:10.1073/pnas.1600092113/-/DCSupplemental.
ErrataCorrection to Supporting Information for "Behavioral contagion during learning about another agent's risk-preferences acts on the neural representation of decision-risk," by Shinsuke Suzuki, Emily L. S. Jensen, Peter Bossaerts, and John P. O'Doherty, which appeared in issue 14, April 5, 2016, of Proc Natl Acad Sci USA (113:3755–3760; first published March 21, 2016; 10.1073/pnas.1600092113). The authors wish to note the following: "We have noticed an error in the description of the fMRI analysis on page 2 of Supporting Information (right column, second full paragraph, lines 2–3), under the paragraph heading 'GLM I.' In the original version of Supporting Information, the parametric regressor representing risk was described as the 'variance of reward,' whereas the accurate description of the regressor that was used in the analysis is the 'standard deviation of reward.'" The SI has been corrected online.
Published - PNAS-2016-Suzuki-3755-60.pdf
Supplemental Material - pnas.201600092SI.pdf
Erratum - pnas.201708546.pdf