Belief bias

Belief bias is a cognitive bias in which someone's evaluation of the logical strength of an argument is biased by their belief in the truth or falsity of the conclusion. This effect has been demonstrated in psychological experiments, and is independent of reasoning ability.

In a series of experiments by Evans, et al., subjects were presented with deductive arguments (in each of which a series of premises and a conclusion are given) and asked to indicate if each conclusion necessarily follows from the premises given. In other words, the subjects are asked to make an evaluation of logical validity. The subjects, however, exhibited belief bias when they rejected valid arguments with unbelievable conclusions, and endorsed invalid arguments with believable conclusions. It seems that instead of following directions and assessing logical validity, the subjects based their assessments on personal beliefs.

Further tests using fMRI scans showed differential cerebral activation between belief-neutral trials, or syllogisms involving obscure terms of which the participants were unaware, and belief-laden trials, or syllogisms that could be influenced by knowledge affecting the believability of conclusions. In the belief-neutral trials, activation was seen in the upper parietal lobe, a region involved in mathematical reasoning and spatial representation. In the belief-laden trials, the additional activation of the front left temporal lobe was observed, a region involved in the retrieval and selecting of facts from long-term memory. This indicated that in belief-laden reasoning, people also drew upon memory in addition to abstract reasoning.

It has been argued that like in the case of the matching bias, using more realistic content in syllogisms can facilitate more normative performance, and the use of more abstract, artificial content has a biasing effect on performance.^{[citation needed]}

See also

• Confirmation bias
• Hostile media effect
• List of cognitive biases

Further reading

• Markovits, H.; G. Nantel (1989). "The belief-bias effect in the production and evaluation of logical conclusions". Memory and Cognition 17 (1): 11–17. doi:10.3758/BF03199552. 
• Klauer, K.C.; J. Musch, B. Naumer (2000). "On belief bias in syllogistic reasoning". Psychological Review 107 (4): 852–884. doi:10.1037/0033-295X.107.4.852. PMID 11089409. 
• Dube, C.; C. M. Rotello, E. Heit (2010). "Assessing the belief bias effect with ROCs: It’s a response bias effect". Psychological Review 117 (3): 831–863. doi:10.1037/a0019634. PMID 20658855. 

External links

• Changing Minds: Belief Bias