Critical thinking & motivation
People will sometimes share stories or memes that are so obviously false that it’s hard to fathom how anyone wouldn’t instantly know it was false, or at least have enough doubt to check snopes. So it seems like they completely lack critical thinking ability. However, if someone from the outgroup makes a bad argument (gets facts wrong or uses bad logic), people seem to quickly identify the problems and express their outrage. Examples: (1) if a loyal Democrats hear a Republican make a bad argument, they seem to be able to provide counter-arguments quickly; (2) if someone who won’t vaccinate their kids hears an argument in favor of vaccines, they are able to identify some possible weaknesses in the argument; (3) if the latest study goes against someone’s beliefs, they all-of-a-sudden remember that correlation doesn’t equal causation.
If your ingroup isn’t threatened, then there isn’t much motivation for most people to use critical thinking. Sharing a story about the latest dangerous teenage trend isn’t about showing people that you know actual facts; it’s mostly about showing that you care about kids or that you are higher status than teenagers. That goal is accomplished by sharing the story.
However, if your ingroup is threatened, you have every reason to put on display your critical thinking skills. All of your ingroup will have the same motivation. You can bond over it. You can all show how devoted you are. And hence we get the blowback effect.
Politicians, bad arguments, devotion, & trolling
As a politician, you can take advantage of this. If you occasionally make a bad argument or get some facts wrong, you accomplish two things. (1) you show your base just how devoted to the cause you are. You aren’t that worried about the facts — you will support this cause regardless. Thus, they can count on you to not change your mind later on, if presented with strong evidence against your belief. (2) you troll the outgroup. The outgroup will be in critical thinking mode when you speak, and if you get some facts wrong or use poor logic they will be outraged.
You obviously can’t go too far with bad arguments and false claims or you will eventually lose credibility, but I think some bad arguments are necessary.