Tendency to selectively look for information that might confirm your belief and overlook information that disconfirms it

Wason (1960) study

• Subjects shown a set of three numbers that were connected by a numerical rule

• They had to discover the rule by proposing additional sets of numbers

• Received feedback about whether each set fit the rule

• They continued until they were confident they knew the rule, then announced it

Initially told that 2, 4, 6 fits the rule

Subjects are given 4,6,8; 6,8,10 which all fits the rule, then conclude: 3 numbers increase by 2 each time.

Actual rule: “Three numbers in increasing order”