Confirmation bias
IB Psychology· Cognitive approach· 11 min read
1. Core concept
Confirmation bias is the tendency to search for, notice and interpret information in ways that confirm what we already believe, while overlooking evidence that would disconfirm it. It shapes reasoning because people test hypotheses by looking for hits rather than for the cases that could prove them wrong. It matters for how beliefs, stereotypes and even scientific claims persist despite contrary evidence.
2. Key studies
IB Psychology answers must be supported by named studies. Learn these to cite as evidence:
Wason (1968)
In the four-card selection task, people typically sought confirming cards rather than the card that could falsify the rule. — A clean demonstration that people seek confirmation rather than falsification.
3. Evaluation (AO3)
Strength — broad explanatory reach — The same tendency accounts for belief persistence, stereotype maintenance and poor hypothesis-testing, and replicates widely.
Limitation — context and rationality — In some real-world settings testing for confirmation is efficient rather than irrational, so the 'bias' label can be too strong out of the lab.
4. Scope
5. Common Pitfalls
Wrong move:
Equating confirmation bias with simply being stubborn or refusing to change your mind.
Why:
A frequently penalised misconception in IB Psychology exams.
Correct move:
It is specifically a bias in how evidence is SOUGHT and interpreted — favouring confirming over disconfirming information — which can happen even in someone trying to be objective.
Going deeper
- Dual processing theoryconfirmation bias, like other biases, reflects fast System-1 processing in the dual-processing model (COG_6).