What is belief bias and what is the best way to avoid belief bias when making decisions?

Belief bias is a conclusion where someone’s assessment of the logical strength of an argument is biased by the believability of the assumption. So for example, if you already have made up your mind that politician A is corrupt then the assertions made with no supporting evidence about politician A’s corruption is far more likely to be believed even though that belief can be wrong due to lack of evidence.

The best way to avoid belief bias when making decisions is to listen/consider the opposite view and listen to them, without being offended or getting angry.