Doctors are also among the highest-paid members of American society and, along with wealthy financial professionals, you will typically find them siding more with the Republican Party often out of concern for their tax bracket.
Professors in humanities that identify as Republican range from 6 to 11 percent.
Social Sciences 7 and 9 percent
2% of English professors are Republican.
Meanwhile 18% of social scientists are Marxists.
This evidence leads me to believe that Academics self select to be liberal and that people with a conservative mindset do not find academia appealing for whatever reason. The reason I rule it has little to do with intelligence of the groups is the prevalence of Marxism amongst academics. Intelligent people that use evidence to reason about their beliefs wouldn't be Marxist.
http://www.nytimes.com/2016/05/08/opinion/sunday/a-confessio...