Brain structure in the parietal cortex may predict how willing people are to take risks
Researchers at Yale School of Medicine report that the size of a specific region in the parietal cortex is associated with individual differences in risk-taking. In a study led by Ifat Levy, assistant professor in comparative medicine and neurobiology, participants with a larger volume in a part of the parietal cortex tended to choose riskier monetary options than those with a smaller volume in that region. The results were published in the Journal of Neuroscience on September 10, 2014.
While previous work has linked certain cognitive and personality traits to brain anatomy, relatively little research has directly tied brain structure to economic decision-making and risk preferences. This study set out to test whether anatomical differences in the brain relate to how people evaluate and accept risk.
The research team recruited young adult men and women from the northeastern United States. Participants completed a series of choices between monetary lotteries designed to vary systematically in risk and reward. Each participant also received a standard anatomical MRI scan so the researchers could measure the volume of different brain regions. The initial findings came from a first cohort of 28 individuals and were subsequently replicated in an independent cohort of 33 participants, strengthening confidence in the association between parietal cortex volume and risk-taking behavior.
Levy emphasized the broader implications of the finding: “Based on our results, in principle it may be possible to examine large collections of existing medical brain scans to estimate population-level risk attitudes.” Such an approach could help explain why different people exhibit different levels of risk tolerance and could inform models that combine neuroscience with behavioral economics.
At the same time, Levy and the team stress that the observed relationship does not establish causation. “We do not yet know whether structural brain differences cause changes in behavior or whether life experiences and decision patterns shape brain structure,” she noted. The direction of influence remains an open question that will require longitudinal and experimental studies to resolve.
The authors point to related findings that risk aversion tends to increase with age and that the cerebral cortex thins as people grow older. These parallel observations raise the possibility that age-related cortical thinning in regions such as the parietal cortex could partly explain changes in risk preferences over the lifespan. Levy said the group is actively investigating that hypothesis and plans to test whether cortical thinning mediates the shift toward greater risk aversion seen in older adults.
Limitations of the study include the relatively small, regionally based sample and the focus on a narrow age range. The research team calls for larger and more diverse samples to determine how generalizable the parietal volume–risk relationship is across populations, age groups, and cultural contexts. Additional research will also be needed to explore how this structural association relates to functional brain activity during decision-making and how environmental, genetic, and developmental factors contribute.
The study was a collaborative effort among researchers at Yale University, University College London, New York University, University of Pennsylvania, and the University of Sydney. In addition to Ifat Levy, authors include Sharon Gilaie-Dotan, Agnieszka Tymula, Nicole Cooper, Joseph W. Kable, and Paul W. Glimcher. The work received funding support from the National Institute on Aging (R01AG033406).
Contact: Karen N. Peart – Yale
Source: Yale press release
Image Source: Image credited to Patrick Lynch and adapted from the Yale press release
Original Research: Published in Journal of Neuroscience on September 10, 2014. DOI: 10.1523/JNEUROSCI.1600-14.2014.