Confirmation Bias

Confirmation bias is the tendency to search for, interpret, favor and recall information in ways that confirm or support a person's prior beliefs, values or expectations, while giving disproportionately less consideration to information that contradicts them. It shows up in how people gather evidence, in how they interpret ambiguous evidence, and in what they remember afterward. The English psychologist Peter Wason's early experiments on hypothesis testing gave the effect its modern experimental grounding and its name, though the underlying tendency had been informally noted by philosophers and scientists long before it was named.