Interesting study and a few write ups about it. Not sure if CEPS is the right place for this but there does tend to be a lot of people with extremist views so thought it would of interest.
The guardians coverage:
www.theguardian.com
Science Daily:
And of course the actual study:
The guardians coverage:

People with extremist views less able to do complex mental tasks, research suggests
Cambridge University team say their findings could be used to spot people at risk from radicalisation
Science Daily:

Psychological 'signature' for the extremist mind uncovered
Study investigates ideological attitudes using an unprecedented number of cognitive and personality tests, and finds that people who lean towards 'extreme pro-group action' have a similar type of mind.
www.sciencedaily.com
And of course the actual study: