Doctor of Philosophy (PhD)



Document Type



The confirmation bias occurs when an individual ignores potentially disconfirming evidence and gives greater attention to apparent confirming evidence. The confirmation bias is theorized to result from rapid, automatic and unconscious processing. Such processing generates decisions that are considered to be “good enough” to meet the demands of a situation. Although such judgments are guided by unconscious processing, the individual may have conscious awareness of the generated hypothesis while still failing to systematically consider important information. Previous attempts to counter the confirmation bias have focused on directly instructing individuals to use systematic decision making. This method has had some success in laboratory tasks but has shown little transfer to real-world, everyday decision making. Systematic processing requires cognitive resources and more time than reliance on automatic processing. Therefore, individuals may refuse to engage in systematic processing unless they have a strong belief that their hypothesis is flawed. The experiments described in this paper attempt to increase participant’s doubt in their flawed hypothesis by calling attention to failure and by increasing the apparent difficulty of the task. Such doubts were expected to increase systematic processing. While focusing attention on failed decisions did increase the time participants spent making decisions, such increased deliberation time did not translate to improved accuracy. However, the experiments support the use of the Matchmaker Task to create a specific bias that can persist over numerous trials.



Document Availability at the Time of Submission

Release the entire work immediately for access worldwide.

Committee Chair

Mathews, Robert C



Included in

Psychology Commons