“As a rule, strong feelings about issues do not emerge from deep understanding,” Sloman and Fernbach write. And here our dependence on other minds reinforces the problem. If your position on, say, the Affordable Care Act is baseless and I rely on it, then my opinion is also baseless. When I talk to Tom and he decides he agrees with me, his opinion is also baseless, but now that the three of us concur we feel that much more smug about our views. If we all now dismiss as unconvincing any information that contradicts our opinion, you get, well, the Trump Administration.
Perhaps when discussing these issues with someone on “the other side”, the most effective route might be an innocent “You know, I don’t understand this issue/policy well. How does it actually work?” I wonder if, as they work through a response and your follow-up questions, the other person might talk themselves out of their certainty.