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Published February 23, 2010 | Supplemental Material + Published
Journal Article Open

Amygdala damage eliminates monetary loss aversion


Losses are a possibility in many risky decisions, and organisms have evolved mechanisms to evaluate and avoid them. Laboratory and field evidence suggests that people often avoid risks with losses even when they might earn a substantially larger gain, a behavioral preference termed "loss aversion." The cautionary brake on behavior known to rely on the amygdala is a plausible candidate mechanism for loss aversion, yet evidence for this idea has so far not been found. We studied two rare individuals with focal bilateral amygdala lesions using a series of experimental economics tasks. To measure individual sensitivity to financial losses we asked participants to play a variety of monetary gambles with possible gains and losses. Although both participants retained a normal ability to respond to changes in the gambles' expected value and risk, they showed a dramatic reduction in loss aversion compared to matched controls. The findings suggest that the amygdala plays a key role in generating loss aversion by inhibiting actions with potentially deleterious outcomes.

Additional Information

© 2010 by the National Academy of Sciences. Edited by Dale Purves, Duke University Medical Center, Durham, NC, and approved January 8, 2010 (received for review September 7, 2009). Published online before print February 8, 2010. We thank Alireza Soltani, Vikram Chib, and Dan Knoepfle for help with the data analysis and Daniel Kahneman for insightful discussions at the time of the experiment's design. Support was received from the Betty and Gordon Moore Foundation (R.A. and C.C.), Human Frontier Science Program (C.C.), the Wellcome Trust (B.D.M.), the National Institutes of Health (R.A.), the Simons Foundation (R.A.), and a global Center of Excellence Grant jointly with Tamagawa University from the Japanese government (C.C. and R.A.).

Attached Files

Published - DeMartino2010p7287P_Natl_Acad_Sci_Usa.pdf

Supplemental Material - pnas.200910230SI.pdf


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