Confirmation Bias

Confirmation bias is the tendency to search for, interpret, favor, and recall information in a way that confirms or supports your pre-existing beliefs. It is one of the most pervasive and well-documented cognitive biases in psychology, affecting everything from casual opinions to scientific research and judicial decisions.

The concept was dramatically demonstrated by Peter Wason in his famous 2-4-6 task in 1960. Participants were told that the sequence "2, 4, 6" followed a rule, and they had to figure out what that rule was by proposing their own sequences. Most people hypothesized "ascending even numbers" and only tested sequences that confirmed this guess (like 8, 10, 12). Very few tried sequences that might disconfirm their hypothesis (like 1, 3, 5). The actual rule was simply "any ascending numbers" — but people's tendency to seek confirming evidence prevented them from discovering this.

In the modern world, social media algorithms have supercharged confirmation bias. Platforms show you content similar to what you have already engaged with, creating echo chambers where your existing beliefs are constantly reinforced. News feeds become mirrors reflecting your worldview back at you, making it progressively harder to encounter — let alone seriously consider — contradicting perspectives. Studies have shown that even when people are presented with balanced evidence on a controversial topic, they tend to rate the evidence supporting their prior view as more convincing and the opposing evidence as flawed.