Generally, no. Objectivity is largely a function of temperament and deliberate effort rather than intelligence. Studies show
I don't know...sounds like these studies were poorly designed if that's what they really show. To be sure intelligent people can be bull headed, but less intelligent people can be bull headed AND incapable of being objective. I know people who are simply intellectually incapable of rational argument. Don't you? Lucky duck.
Uninformed voters are more easily swayed with information challenging their beliefs, but people who know and have strong opinions
I think you may be confusing being wishywashy with having objectivity. I know people who will hold the last opinion presented to them...right up until they are presented with another argument. Some of these people are incapable of evaluating, or forming rational argument. Many of them lack any problem solving skills. While I don't know their IQ, I suspect they are on the low side. Not scientific I know, but I wouldn't be surprised if a scientific study could be designed that would confirm that.
Objectivity takes training and deliberate practice.
I agree. I simply suggest that it also takes discipline, honesty and an IQ capable of evaluating rational argument. Put another way, the higher the IQ the easier it is to be objective. Not saying everyone takes advantage of their IQ in this regard.