Nov 4, 2020
*** There is a transcript available for this episodes at
Yuan Chang Leong, PhD, spoke with Psychcast host Lorenzo Norris,
MD, about his research into the neural underpinnings of right- and
Dr. Leong is a
postdoctoral scholar in cognitive neuroscience at the University of
California, Berkeley. He has no disclosures.
Norris has no disclosures.
- Dr. Leong and colleagues looked for further evidence of “neural
polarization,” which is defined as divergent brain activity based
on conversative versus liberal political attitudes.
- The prefrontal cortex is the part of the frontal lobe
responsible for executive and higher-order brain function that
makes sense and organizes what a person is seeing, hearing, and
- Participants were shown news clips about immigration policy and
their brain activity showed differences in activity of their
dorsomedial prefrontal cortex (DMPFC), which is active in
interpreting narrative content. The findings suggest there is a
neural basis for the way in which individuals with different
political attitudes interpret political information and news.
- The research suggests that words related to threat, morality,
emotions, anger, and differentiation/community drive neural
- Dr. Leong and colleagues asked participants to watch news clips
about immigration policy while undergoing functional MRI with the
goal of identifying the neural correlates of neural polarization,
which is thought to parallel the behavioral aspects of political
- Dr. Leong and colleagues identified an association of
divergence in connectivity to the DMPFC to the ventral striatum, a
structure involved in reward processing and sensing the valence and
tone of information. Their
study, published in the Proceeding of the National Academy of
Sciences, suggests that information from the ventral striatum is
transmitted differently to the DMPFC between groups.
- The findings suggest that our political beliefs might influence
our interpretation of other information, as the DMPFC helps humans
interpret narrative content.
- Dr. Leong pointed out that this study provides evidence about
why it is so difficult to bridge the partisan divide. He also
discussed the psychology of social identity theory and how any
categorization of people makes individuals think along the lines of
in-group and out-group, and how the human drive is to protect the
Leong YC et al. PNAS. 2020 Oct 20. doi:
McLeod S. Social identity theory. Simply
Psychology. Updated 2019.
University of Texas, Austin. Ethics unwrapped. In-group/out-group
Brooks M. Brain imaging reveals a neural basis for partisan
politics. Medscape.com. 2020
Show notes by Jacqueline Posada, MD, associate producer of the
Psychcast; assistant clinical professor in the department of
psychiatry and behavioral sciences at George Washington University,
Washington; and staff physician at George Washington Medical
Faculty Associates, also in Washington. Dr. Posada has no conflicts
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