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15 ways your brain is messing with you.
Used well, intuition can cut through a decision like butter. Used badly, it leads us down some shady alleys. It's quick to judge and slow to correct itself.
In my article on intuition, I explained how a gut feeling is really your brain reaching a conclusion without conscious thought, usually delivered as an emotion or a physical sensation. Think of the brain as a prediction machine: the hippocampus, its librarian, constantly checks incoming data against your memories. A familiar pattern gets a "match" and waved through; something unexpected triggers a "mismatch" that pings the amygdala, which raises the alarm as a feeling. Handy when it stops you hitting a pothole. Less handy the rest of the time.
When intuition misfires
Because intuition matches experience against memory, it's only reliable in areas where you have plenty of relevant memories. Worse, when the brain meets something new, it tends to filter out exactly what made it novel, squeezing it into an existing pattern. As Eric Bonabeau puts it, "intuition is a means not of assessing complexity, but of ignoring it." Our brains evolved to see patterns everywhere, so we spot them even in random noise. Those simplifying errors are called cognitive biases, mental shortcuts that are often just plain wrong. Borrowing Buster Benson's framing, here are fifteen of the most common, grouped by the four problems the brain is trying to solve.
Problem 1: too much information
1. We notice things that are repeated often enough. The illusory truth effect: repeat something often enough and people start to believe it, true or not.
2. We prefer what's already been primed in memory. Anchoring: we lean on the first piece of information we're given, which is why salespeople show you the premium option first.
3. We're drawn to what confirms our beliefs. Confirmation bias: we seek out information that supports what we already think, and miss what doesn't.
4. We think we see more of the world than we do. The "invisible gorilla" experiments show that when we focus hard on one thing, we go blind to obvious events outside that focus.
Problem 2: not enough meaning
5. We project today's mindset onto past and future. Hindsight bias: after the fact, we're sure we'd have predicted it, which breeds over-confidence.
6. We lean too far towards optimism. Normalcy bias fools us into assuming things will carry on as they always have, so we underestimate the odds of things going wrong.
7. We assume things we like are better than they are. The halo effect: a good overall impression of someone bleeds into how we judge their individual qualities.
8. We think we know what everyone's thinking. The spotlight effect: we're at the centre of our own universe, but not anyone else's, and people notice us far less than we fear.
9. We look where it's easiest, not where the answer is. The streetlight effect: as Esther Perel notes, we search where the light is, not where the truth is most likely to be found.
Problem 3: needing to act fast
10. We feel too confident. The Dunning-Kruger effect: the less we know, the less we realise there is to know. As Bertrand Russell put it, "the fundamental cause of trouble in the world is that the stupid are so confident and the intelligent so full of doubt."
11. We over-value what we've already invested in. The sunk-cost fallacy: we stick with something, a job, a relationship, a project, partly because of all the time and energy we've already poured in.
12. We defer to the highest-paid opinion. The HiPPO effect: when good data is missing, groups tend to follow the most senior person's view rather than the best argument.
Problem 4: not knowing what to remember
13. We edit and reinforce memories after the event. Misattribution of memory: we can vividly "remember" things that happened to someone else, or never happened at all.
14. We generalise. Unconscious bias: a prejudice for or against a person or group that none of us is fully immune to, however aware we believe we are.
15. We remember images better than words. The picture superiority effect means our intuition is more likely to match what we've seen than what we've merely heard.
Seeing the world as it is
Intuition can be a tremendous ally, but it runs on ancient, fast information-processing that's prone to distraction and error. Trust your gut only where your bank of memories is genuinely large enough for accurate matching, and even then, test it against the biases above. As one writer puts it, we're not built to perceive the world as it actually works, we're built to perceive it in ways that helped us survive. So lean into that sixth sense, but keep a third eye out for the gorillas and the hippos.
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