Engineers are vastly over-represented among extremists
The researchers found that the over-representation of engineers held true in other contexts. Of the 40 jihadists who studied at universities abroad, 27 were engineers. In another data set, comprising 71 extremists who were born or grew up in Western countries, 32 were engineers.
The relationship extended beyond Islamist movements to other extremist groups. Violent neo-Nazis and neo-Stalinists in Russia and neo-Nazi and white-supremacist groups in the United States also showed disproportionate numbers of engineers.
The article lists some possible theories for why this is: distaste for ambiguity, certainty thinking, etc.
Here's an earlier version of the paper
Here's a later version of the paper