11. Babble Hypothesis: According to multiple studies, what best predicts whether someone becomes a leader? Their experience? Their IQ? No! The amount of time they spend talking. It doesn't even matter what they say, just how much they say it. We suck at picking leaders.
12. Granfalloon: We categorize people into meaningless groups: the physics "community," the black "community." The people in these "communities" often have little in common, but we treat them like they think with one mind, and shockingly, some even claim to speak for them.
13. Social Influence Bias: You can't trust customer ratings, because each rating is influenced by the previous ones. People will rate something higher if the current rating is very low or very high. The result is that many things have far higher customer ratings than they should.
14. Rolestorming: Having trouble being creative? Then pretend you're someone else, maybe Winston Churchill, or Lady Gaga, or Yoda. Continue to do your work while roleplaying as that person, imagining how they'd do your job. Enable you to think outside the box, this will.
15. Psychogenetic Fallacy: Instead of assessing an opponent's claim on its own merits we instead diagnose them as having a certain bias or prejudice that motivated them to make the claim. What we never consider is that maybe they know something we don't.
16. Semantic Apocalypse: In the digital age, we all live in subcultures. Society is no longer bound by a shared set of beliefs. All that unites us is our common biology: our fears & hunger. We've created a civilization organized around nothing but our shared animality.
17. Beginner's Bubble Effect: The most ignorant people are not those who know nothing about something, but those who know a little about it, because their little knowledge gives them the illusion of understanding, which makes them overconfident in their beliefs. h/t: @emollick
18. Selective Laziness: We're critical of others' arguments but not our own. Trouche et al (2016) found that showing people their own claims disguised as another's led them to reject the claims. To know what you really think about your beliefs, imagine they're someone else's.
19. Nominal Fallacy: We label things to avoid having to think about them. For example, calling a murderer "evil" to explain their behaviour absolves us of the need to confront the complex web of circumstances that led them to murder.
20. Ad Hoc Rescue: We grow so attached to our beliefs that we begin to defend them like lawyers defending clients, using every trick we can to find loopholes that'll allow us to keep believing. As @PTetlock said: "Beliefs are hypotheses to be tested, not treasures to be guarded."