We take ourselves for reasonable creatures. We weigh things up, gather information and then — so we believe — make well-founded decisions. Cognitive psychology has been showing for decades that this is an illusion.
Our thinking follows systematic shortcuts that made sense in evolutionary terms but often lead us astray in the modern world. The shortcuts are called heuristics; the errors they produce are called cognitive biases.
The brain as a miser
The human brain accounts for only two percent of body weight but consumes about 20 percent of the body's total energy. No wonder, then, that it has developed energy-efficient strategies. Psychologists call these mental shortcuts heuristics: they allow fast decisions under uncertainty, and they also produce systematic errors.
Daniel Kahneman and Amos Tversky laid the ground for this field in the 1970s. Their work showed that people do not decide like the "rational actors" of classical economics but depart from them in predictable patterns.
Five biases that keep us company every day
- Confirmation bias — We prefer information that supports the beliefs we already hold and screen out what contradicts them. That makes us resistant to facts which threaten our picture of the world, and it explains why political camps so often talk past one another.
- Availability heuristic — What comes to mind easily we take to be more likely. After a plane crash the fear of flying rises, although statistically the car remains far riskier. News coverage amplifies this effect considerably.
- Anchoring effect — The first number we hear influences every later estimate, even when it is entirely arbitrary. Sellers use this deliberately: a high opening price makes the later "discount" look more attractive.
- Loss aversion — Losses hurt about twice as much as equally large gains please. That is why many investors hold on to falling shares for too long and pass up sensible risks. Kahneman and Tversky's prospect theory describes the effect precisely.
- Dunning-Kruger effect — People who know little about a field systematically overestimate their competence. Experts, conversely, often underestimate their knowledge because they can see how complex the field is. The result is a dangerous combination of ignorance and confidence.
Terms Shortcut or error?
A heuristic and a bias are not the same thing. A heuristic is a decision rule for limited time and limited knowledge — and in most situations it works. A bias is what we call it where that same rule is systematically wrong. The problem is not the rule itself but the context it is applied in.
We are not as rational as we like to believe — but we are systematically irrational. And that is exactly what makes us predictable.
Can we do anything about it?
Cognitive biases cannot be eliminated entirely; they are part of the architecture of our thinking. But they can be softened. Three evidence-based approaches have proved helpful.
Train metacognition: question your own thought processes regularly. Questions such as "which information am I ignoring right now?" or "would I judge the same way if the starting position were reversed?" can help.
Bring in outside perspectives: other people often see our blind spots more clearly. In organisations, structured decision processes and "red teams" that deliberately look for counter-arguments do this work.
Encourage statistical thinking: anyone who understands relative frequencies and base rates falls less easily for availability and representativeness errors. Even simple exercises with probabilities improve judgement measurably.
Why knowing about biases can be a relief
Realising that our thinking is error-prone is sobering at first. But it has a liberating side as well: many of our bad decisions are not a sign of stupidity or weak character but an expression of universal psychological mechanisms.
Someone who understands why they keep making the same mistake in certain situations can begin to counteract it. Not through willpower alone — that is astonishingly limited — but through better environments, better questions and the courage to put one's own convictions to the test regularly.
What is this article based on?
This piece draws on Kognitive Verzerrungen, a review written for Parilem by Prof. Dr. Dilek Kılıç.
- Kahneman, D. (2011). Thinking, Fast and Slow. Farrar, Straus and Giroux.
- Tversky, A. & Kahneman, D. (1974). Judgment under Uncertainty: Heuristics and Biases. Science, 185(4157), 1124–1131.
- Kahneman, D. & Tversky, A. (1979). Prospect Theory: An Analysis of Decision under Risk. Econometrica, 47(2), 263–291.
- Kruger, J. & Dunning, D. (1999). Unskilled and unaware of it. Journal of Personality and Social Psychology, 77(6), 1121–1134.
- Nickerson, R. S. (1998). Confirmation Bias: A Ubiquitous Phenomenon in Many Guises. Review of General Psychology, 2(2), 175–220.
Dilek Kılıç
Works on neurology at Heidelberg University. Runs joint projects with India.
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