Why is it sometimes so hard to convince someone that the world is indeed a globe, or that climate change is actually caused by human activity, despite the overwhelming evidence?

The test takers had no clues as to what a Daxxy was or wasn't, but they did get feedback after guessing one way or the other – the system would tell them if the shape they were looking at qualified as a Daxxy or not. At the same time they were also asked how sure they were about what a Daxxy actually was.

In this way the researchers were able to measure certainty in relation to feedback. Results showed the confidence of the participants was largely based on the results of their last four or five guesses, not their performance overall.

Well, they've admitted we aren't "unintelligent" - just misled by feedback.

Thus substantiating some kind of separation of people with "incorrect and similar beliefs"?

Not to mention the test itself sounds completely ridiculous and asinine.