There is virtually no connection between cognitive ability (IQ) and how folks feel (ego drive) about things in general. In other words a suicide bomber on average will test no different IQ wise than, say, a Peace Corp volunteer.
Indeed it’s not the ability to learn quickly that separates a Bernie Sanders backer from a Trump supporter. Rather the difference is width of interest — intellect.
If you were to poll Bernie and Trump supporters there is no doubt in my mind that Bernie’s supporters would be found to be far better read on a wider variety of subjects than Trump supporters. Yet an IQ test would find little difference in raw intelligence between the two groups.
I strongly suspect, however, that you would find Trump supporters to be what I call ego-locked. Meaning that they are almost exclusively concerned only with those things that directly affect (ego stimulate) their lives — friends, family, work, religion and hobbies and sports — a small curiosity horizon.
In other words because of a lack of curiosity with things beyond their own day-to-day activities, they lack the sort of broad perspective concerning culture, history and politics that makes them ease pray for guys like Trump.