The connection between brain structure and ideology: MRI scans of 975 Dutch individuals aged 19 to 26 found that conservative people’s amygdalas are slightly larger (by the size of one sesame seed out of 157), though the difference is smaller than expected
https://www.uva.nl/shared-content/uva/en/news/press-releases/2024/09/study-among-dutch-people-adds-nuance-to-link-between-brain-structure-and-ideology.html
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>The claim that brain structure and ideology are linked was fueled by a 2011 study of 90 English students that found this connection. Scientists at the UvA have now conducted the largest replication study to date to further investigate the relationship between ideology and brain structure.
>The scientists found, just as in the English study, that the amygdala of conservative people is slightly larger. ‘It is remarkable that we also found this result in our much larger and more representative sample. For example, the English sample did not contain any extremely conservative participants, while ours did,’ says Schumacher.
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>The scientists also found that there is no relationship between another brain area – the anterior cingulate cortex – and ideology, something that the original study did find.
>The difference in the amygdala was the size of a sesame seed. ‘The amygdala of the average conservative voter is 157 sesame seeds in size and that of the average progressive voter is 156 sesame seeds. That is a small difference, but significant. It suggests that there is a connection between brain anatomy and ideology at some level, but that it is very indirect,’ explains co-author Steven Scholte. ‘Our expectation was therefore to find no effect at all.’
>The researchers then extended their analysis to find connections between ideology and other brain areas. For example, they found a connection between the volume of the right fusiform gyrus, an area of the brain important for facial recognition, and more right-wing positions on social and economic issues. The reason for this remains to be seen.
Paper: [Is political ideology correlated with brain structure? A preregistered replication: iScience](https://www.cell.com/iscience/fulltext/S2589-0042(24)01757-7)
One sesame seed out of 157? What does that mean?
We live in an idealist society where almost everyone seems to think volition happens via the metaphysical magic of “intention” or something. As the decades go by we’re going to get more and more detail on why we are the way we are, and instead of chocking things up to “bad person, good person” we will see the genesis of them and their psychology.
Has science really got to the point where “one sesame seed” is used as a unit to measure volume?
As an MRI scientist I’m begining to feel like a lot of this field is phrenology.
Many (most?) studies in this area [don’t focus on size or structure as much as function (connectivity, activity)](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5793824/).
Is this also why alligators are so ornery?
It’s difficult to find accurate figures, but back-of-the-envelope calculations put that at somewhere around 900,000 extra fear and disgust neurons in a conservative brain.
So would the size of a sesame seed based banana be significantly larger at the same mass?
It’s substantial, also makes sense if you think about the way many conservatives interpret information. It’s a fear-based dynamic. What could go wrong, what’s about to go wrong, what will go wrong etc
Are we going to be measuring skull volumes and philtrum lengths next?
Is that Jack’s paranoia?