Mk VII, have you a link to the specific survey? I have big issues with many of these types of surveys, in the way they phrase questions vs. they way they report the findings. Such as giving the interviewee a blank map of the world, with only continent outlines, and asking them to point to Afghanistan. I’m only 80% confident I’d be on target, if Iran and Pakistan weren’t clearly identified!
As for the ‘fictitious character’, it was probably multiple choice, with three fictitious historical characters. So somebody with, umm, less than average intelligence & education, could easily be bewildered and take a random guess. And one in four of those guesses would be for Hitler.