Concept · Cognitive Bias: Decision-making and judgment biases
Confirmation bias
Origin: Wason, 1960; Nickerson, 1998 (review)
The Biological Bridge
This business construct is human-invented, but the outcome it's trying to achieve has deep biological roots.
Surface Construct
Seeking information that confirms existing beliefs
↓
Underlying Outcome
Efficient hypothesis testing in information-scarce environments
↓
Biological Mechanism
Positive evidence gathering. In environments where information is costly to acquire, seeking confirming evidence for working hypotheses is efficient. A forager who found berries at a bush yesterday should check that bush first today - not randomly sample all bushes to 'avoid confirmation bias.' The bias saves energy when priors are good.
Key Insight: Confirmation bias is efficient Bayesian updating when priors are accurate and information is costly. It fails when priors are wrong or information is cheap.
The Full Picture
Vervet monkeys have distinct alarm calls for eagles, snakes, and leopards—but they false-alarm constantly for branches that look like snakes because the cost of confirmation bias (wasted energy) is trivial compared to the cost of disconfirmation error (death). Natural selection doesn't value truth; it values fitness. Organisms evolve to see what they expect to see when false positives are cheap and false negatives are fatal. Our brains inherited this asymmetry: better to hallucinate a predator that isn't there than miss one that is.