I worried that this study might be circular reasoning in that way. Instead they quizzed knowledge on related fields but not directly connected to the disputed idea.
The people involved bet higher amounts on their ability to score well on objective measures of related sciences, but scored worse.
At some level you might reasonably expect what you described to be tautological: the person holding the mainstream view knows more about they things surrounding that view. But do they know the alternatives?
It’d be interest to compare the knowledge level the person holding the consensus view has about the non-consensus view to vice versa.
That's a great question -- harking back to the idea that for the best incarnation of debate one should be able to argue one's opponent's case to their satisfaction, and then make one's own counter.
The unfortunate problem is that it's often far easier to cook up BS than to bust it, so the anticipated effort tilts the scales massively. But in cases where there are specific/highlighted competing alternatives, it would be very interesting to study this.
No, because the things they're asking about are middle school level science stuff.
The list of questions are in the supplemental PDF, or in my comment at https://news.ycombinator.com/item?id=32379920