Question
Can smart people be irrational?
Short answer
Yes. Across seven studies, many classic thinking biases, including framing, anchoring, base-rate neglect, myside bias and the sunk-cost effect, were uncorrelated with cognitive ability. High scorers avoided some other biases more often, but intelligence and rational thinking are related only in part.
Want your own number? The test is 25 visual puzzles, about 12 minutes, no sign-up.
Intelligence and rationality are different things
A widely cited 1994 statement signed by 52 researchers defined intelligence as a very general mental capability that includes the ability to reason, plan, solve problems and think abstractly (Gottfredson, 1997). Rationality is narrower and more practical: weighing evidence fairly, noticing when a question has been framed to steer you, and not throwing good money after bad. You might expect the two to go together. The research says they overlap less than you would think.
What the studies found
Keith Stanovich and Richard West ran seven studies comparing cognitive ability with performance on classic tests of thinking bias. Many well-known biases, including framing effects, anchoring, base-rate neglect, myside bias and the sunk-cost effect, were uncorrelated with cognitive ability (Stanovich & West, 2008).
The picture was not entirely flat. Higher ability did go with avoiding some biases, including denominator neglect, probability matching, belief bias and matching bias on a well-known logic task (Stanovich & West, 2008). Those tend to be problems where noticing the trap and working through the logic is enough.
Try one · Pattern Recognition
Which tile comes next?
Tap the option you think is right, or show the answer.
Show the answer
The missing tile shows a tiny hatched pentagon (option 5).
How to solve it
- Compare neighboring tiles and name what changes each time.
- From tile to tile, the pentagon gets smaller.
- The fill cycles hatched, solid and outline, then starts again.
- Everything else stays the same from tile to tile.
- The last tile shows a small outlined pentagon. Apply each change once more.
- So the missing tile shows a tiny hatched pentagon.
That was 1 puzzle. The full test has 25.
Why a smart person can fall for a framing trick
An IQ test hands you a clear problem and asks for the one right answer. Many everyday mistakes happen before any reasoning starts: you accept the frame you were given, anchor on the first number you hear or look harder for evidence that agrees with you. Reasoning ability helps only if something prompts you to use it.
What to take from this
- A high score is not a license to trust your first impression.
- For what IQ does and does not predict, see IQ and life outcomes and is IQ the same as intelligence.
- For other abilities that matter beyond IQ, read executive function and emotional intelligence.
Sources
- Stanovich, K. E., & West, R. F. (2008). On the relative independence of thinking biases and cognitive ability. Journal of Personality and Social Psychology, 94(4), 672-695. doi.org/10.1037/0022-3514.94.4.672
- Gottfredson, L. S. (1997). Mainstream science on intelligence: An editorial with 52 signatories, history, and bibliography. Intelligence, 24(1), 13-23. doi.org/10.1016/S0160-2896(97)90011-8