- Interpretation - When giving evidence both for and against your belief, the bias tends to focus only on the evidence for your belief and ignore evidence against your belief
- Search for information - You seek evidence from someone you know agrees with you and do not seek evidence from those that disagree with you.
- Memory - you tend to remember evidence that supports your argument and forget evidence that contradicts your position
There are two times confirmation bias can be observed, when you first develop an idea and when you are presented with new evidence that contradicts one of your existing ideas. If confirmation bias can be avoided in the former, the easier it will be managed in the latter. However, many people, myself included, have adopted ideas without fully evaluating all the evidence for and against when initially presented to them. Young kids are particularly susceptible. This may require re-evaluation of ideas that were once closely held. I have done this before when I reevaluated my belief in God and my interaction with The Objectivist Center, both of which led me to reject my earlier decisions based on new evidence.
2. Internal validity looks at the internal logic of an argument. Ask yourself if the evidence presented shows only part of the picture. Ask yourself if you have fully considered ALL of the evidence. Ask yourself if the conclusions are as solid as claimed. It may help to break up the argument into all of its component parts and verify that evidence supports each part. In short, play "devil's advocate" to establish internal validity.
3. External validity verifies an idea is consistent with the wider context of one's knowledge base. Ask yourself if this conclusion is true, what does it mean for other ideas. Ask yourself honestly what the evidence means for my life. The conclusion from the evidence should integrate with knowledge you already have without contradictions. If it doesn't, either something is wrong with your new conclusion or something is wrong with your existing ideas.