Cognitive Biases: The Mental Shortcuts That Trip Up Even Smart People
Anyone who studies cognitive biases eventually discovers that they have them too. Being smart does not protect you from thinking badly. In 1974, psychologists Daniel Kahneman and Amos Tversky published "Judgment under Uncertainty: Heuristics and Biases" in Science, showing that people use mental shortcuts to judge and decide, and that those shortcuts produce systematic errors. Kahneman received the Nobel Prize in Economics in 2002 for this work; Tversky had died in 1996. Since then, the catalog of described biases has only kept growing.
What a cognitive bias actually is
It is a predictable pattern of error in how we process information. The shortcuts behind it, called heuristics, are not absurd flaws: they usually work and save us effort. The trouble starts when a situation fools them and the shortcut sends us toward the same kind of mistake over and over. Years later, Kahneman explained this through his idea of two systems: one fast and intuitive, the other slow and deliberate, which kicks in less often than we think.
Four biases worth knowing
- Anchoring. A prior number contaminates your later estimate. In a famous experiment by Tversky and Kahneman, a wheel landed on either 10 or 65, and people were then asked what percentage of African countries belong to the United Nations. Those who saw 10 gave an average estimate far lower than those who saw 65, even though the wheel was obviously irrelevant.
- Confirmation. We tend to seek out and value information that supports what we already believe. In 1960, Peter Wason showed it with his 2-4-6 task: participants proposed sequences that confirmed their hypothesis and almost never tried sequences that could prove it wrong.
- Availability. We judge how likely something is by how easily an example comes to mind. That is why a heavily covered plane crash frightens us more than far more frequent everyday risks, like driving.
- The conjunction fallacy. In the Linda problem (1983), many participants judged it more likely that a woman was "a bank teller and a feminist activist" than simply "a bank teller." That is impossible, since the second includes the first.
A high IQ is not a vaccine
Not reliably. Psychologist Keith Stanovich and colleagues have argued for years that intelligence and rationality are different things. In a 2012 study, West, Meserve and Stanovich found that the "bias blind spot," the tendency to see biases in others but not in yourself, did not shrink with cognitive ability. Someone very good at tests can be as vulnerable as anyone to certain errors of judgment, and sometimes better equipped to justify them.
A note of honesty: psychology has popular concepts that have come under scrutiny. The Dunning-Kruger effect is cited constantly, but part of its interpretation is disputed among statisticians. Be cautious with any "law of the mind" that sounds too neat.
Ways to blunt their effect
- Slow down on important decisions. A one-minute pause activates deliberate thinking.
- Look for what contradicts you. Ask what evidence would change your mind.
- Think in base rates. Before judging an individual case, find out what usually happens in general.
- Ask for a second opinion from someone who does not share your view.
- Write down your predictions and check later how many you got right.
The bias of judging yourself
We are also biased when we evaluate our own reasoning, and it is among the subtlest. We tend to believe we reason more objectively than other people and that, when two people disagree, the mistaken one is the other. We also tend to explain our successes with our qualities and our failures with circumstances, and do exactly the reverse with others. A good exercise is to ask what you would tell someone else who had reached your conclusion from your evidence.
Shifting perspective like that does not eliminate the bias, but it weakens it, and it is one of the simplest and cheapest tools there is for thinking a little better. Biases are not a sign of stupidity but a feature of the human brain. Knowing about them does not erase them, though it gives you more chances to catch them in time.
Our test includes questions where the first intuitive answer is not always the right one. If you want to watch a mental shortcut lead you astray, give it a try and notice the moments when your mind rushes.
