I've long hypothesised that a certain phenomenon may exist, and I wonder if there's any actual research on the subject.
I'm asking for research, statistics, etc. on a macro level. However, I think it's easier if I describe the concept on a micro-level, using Bob as an example. This is only an illustration of the concept, it's not the actual question:
Bob has political views that are not considered politically correct by society at large. Some of them are considered racist by many. Some of the proposals he supports are considered unrealistic, populist or very detrimental by mainstream outlets. The views Bob holds are often warned against as racist, dangerous, etc. by media, academics, large-party politicians, etc.
Now, in spite of these views being seen as politically incorrect, Bob still holds them. However, during lunch hour, when his colleagues talk negatively about those very views, he does not join the discussion. Instead, he pretends he agrees with his colleagues, or at least, he keeps his mouth shut. Not only is he afraid of being socially excluded at work, on a certain level he is also internally embarrassed and somewhat conflicted about the views. So he keeps these views secret, hiding them from his family, friends and even strangers. He also feels embarrassed within himself over this. However, in spite of the embarrassment, his predominant feeling is that the views are correct.
There is an upcoming election, and one of the candidates or parties promotes many of the same "politically incorrect" views that Bob holds.
One day, Bob is called up by a pollster. They ask him who he intends to vote for in the upcoming election. Even though Bob doesn't know this person, he still doesn't like to reveal his secret views to another human being. (Even a stranger.) So, he says that he is going to vote for another party/candidate. Or he declines to answer.
However, when the actual election comes, he can vote without saying it to another human being. He can just drop his vote in the ballot box. So he does so, for the candidate/party he actually likes. (The "politically incorrect" one.)
So, what I'm asking is: Is there research or statistics showing whether controversial or "politically incorrect" candidates/parties tend to do better or worse in actual elections than in polls?
I realize defining what a "politically correct" or controversial candidate/party means is somewhat subjective. But most political research involves some subjective judgements.
Reason for bounty: I am happy with the currently accepted answer, and tend to support its ideas personally.
However, during a course on philosophy of science at Oslo Metropolitan University, my lecturer was discussing this exact topic. I brought up social desirability bias and she seemed almost dismissive of it, saying pollsters and statisticians have ways to account for that, and she brought up some other theories (such as respondents in polls not actually matching the voting population. For example, the voters of Candidate A may really dislike polls, or not have telephones).
To be honest, I am not sure I agree with my lecturer, but I still want to hear some various perspectives and get more responses to this question.
I am really happy with the accepted answer, and personally it rings true to me. The purpose of the bounty is just as the notice says, to "draw attention". I am open to other answers and theories, it would be interesting.