These psychological results are only true for average people, note how in every experiment there are always many people who does the rationally correct thing to do. So there is no reason to believe based on those studies that people who have much higher levels of rationality doesn't exist.
Its just, many will believe they are rational when they aren't, since their lack of rationality makes them unable to see all the ways they are irrational. But people who notice their own irrationality can just stop doing those things and change their views and therefore becomes much more rational than average.
So we have several layers, we have those who don't see their own irrationality and call themselves rational, we have those who see their own irrationality and call themselves irrational since they are, and then we have the ones who see their own irrationality and takes measures to fix it and therefore call themselves rational. The last group would be the most rational ones, but is still often mistaken for the first group.
Its just, many will believe they are rational when they aren't, since their lack of rationality makes them unable to see all the ways they are irrational. But people who notice their own irrationality can just stop doing those things and change their views and therefore becomes much more rational than average.
So we have several layers, we have those who don't see their own irrationality and call themselves rational, we have those who see their own irrationality and call themselves irrational since they are, and then we have the ones who see their own irrationality and takes measures to fix it and therefore call themselves rational. The last group would be the most rational ones, but is still often mistaken for the first group.