Trust in beliefs

Don’t assume your beliefs are correct.

People often look for and believe information that confirms what they already believe or want to be true. This is also true for claims about the effects of things they do for their health (health actions). On the other hand, they tend not to seek and perhaps even to avoid information that contradicts their beliefs. 


People tend to seek and focus on information that they consider supportive of their existing beliefs, and to interpret information in ways that uphold those beliefs. People may also ignore evidence or arguments that challenge their beliefs. This is sometimes called ‘confirmation bias.’

Confirmation bias may explain people’s tendency to believe that a health action was responsible for a particular result. This may be because people decide to take a health action to have a desired result. If the desired result occurs, the natural tendency is to think that it is due to the health action that the person decided to take because of their belief that it would cause the desired result. People often do not seriously consider the possibility that the result might have occurred without the health action.

Confirmation bias is also found in research. In comparing citations of articles published in medical journals, researchers found that articles in which the authors concluded that their results supported their original hypothesis were cited almost three times more than articles that did not. This can lead to wrong conclusions and decisions.


When looking for health information, many people search the Internet. However, the information they select, and their interpretation of that information may be biased by their existing beliefs. For example, parents of young children are more likely to select information about vaccination that is consistent with their pre-existing beliefs about vaccination than information that is not. They also consider information that is consistent with their beliefs as being more credible, useful and convincing.

Remember: Don’t be too sure about your beliefs, unless they are based on the results of systematic reviews of fair comparisons of health actions.

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