The ‘signature’ is up to 15 times more effective in identifying potential extremists than current methods - and could be used to identify people who are vulnerable to radicalisation.
Another trait linked to extremism is slower unconscious cognition - the way our brains take in basic information such as shape and colour.
"Many people will know those in their communities who have become radicalised or adopted increasingly extreme political views, whether on the left or right,” said Dr Leor Zmigrod, lead author from Cambridge's Department of Psychology.
We want to know why particular individuals are more susceptible."
"By examining 'hot' emotional cognition alongside the 'cold' unconscious cognition of basic information processing we can see a psychological signature for those at risk of engaging with an ideology in an extreme way.”
"Subtle difficulties with complex mental processing may subconsciously push people towards extreme doctrines that provide clearer, more defined explanations of the world, making them susceptible to toxic forms of dogmatic and authoritarian ideologies."
The study also throws light on the differences between conservatives and liberals.
The study maps the psychological signatures that underpin fierce political conservatism, as well as "dogmatism": people who have a fixed worldview and are resistant to evidence.
Psychologists found that conservatism is linked to cognitive "caution": slow-and-accurate unconscious decision-making, compared to the fast-and-imprecise "perceptual strategies" found in more liberal minds.
Brains of more dogmatic people are slower to process perceptual evidence, but they are more impulsive personality-wise. The mental signature for extremism across the board is a blend of conservative and dogmatic psychologies.
Researchers from the University of Cambridge say that this research could help to better identify and support people most vulnerable to radicalisation across the political and religious spectrum.
Approaches to radicalisation policy mainly rely on basic demographic information such as age, race and gender.
By adding cognitive and personality assessments, the psychologists created a statistical model that is between four and fifteen times more powerful at predicting ideological worldviews than demographics alone.
Zmigrod previously published findings on links between cognitive "inflexibility" and religious extremism, willingness to self-sacrifice for a cause, and a vote for Brexit.
A 2019 study by Zmigrod showed that this cognitive inflexibility is found in those with extreme attitudes on both the far right and far left of the political divide.
The latest research builds on work from Stanford University in which hundreds of study participants performed 37 different cognitive tasks and took 22 different personality surveys in 2016 and 2017.
Zmigrod and colleagues, including Cambridge psychologist Professor Trevor Robbins, conducted a series of follow-up tests in 2018 on 334 of the original participants, using a further 16 surveys to determine attitudes and strength of feeling towards various ideologies.
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