1) The document discusses confirmation bias, where a person only pays attention to information that confirms their existing beliefs and ignores information that contradicts their beliefs.
2) The author provides an example of how they ignored claims made by an acquaintance who was known to exaggerate or lie, because they had already determined not to believe anything that person said.
3) However, the author was more open to claims from their best friend, believing they would not lie.
4) During a social psychology lecture, the author realized they had demonstrated confirmation bias by ignoring the acquaintance's claims while believing their best friend.