This is an important cause of bias in judgement. The Psychology and Society online glossary provides the following examples of confirmation bias:
"A student who is going to write a research paper may primarily search for information that would confirm his or her beliefs. The student may fail to search for or fully consider information that is inconsistent with his or her beliefs.
A reporter who is writing an article on an important issue may only interview experts that support her or his views on the issue.
An employer who believes that a job applicant is highly intelligent may pay attention to only information that is consistent with the belief that the job applicant is highly intelligent."