Why do we have belief perseverance?

Belief perseverance is the tendency for people to hold their beliefs as true even when their is credible evidence to prove that belief as wrong or false. for example, take a conspiracy theorist. a conspiracy theorist may believe that their theory of an event or an explanation to something may is true even though there is plausible evidence against it. we sometimes use this in everyday life, our minds twisting memories in order for us to believe we did nothing wrong in bad situations. another example, say you had to do chores today and your mother or father called out for you to do them. time and time again they call out for you but you may sit there on your phone or whatever else may be occupying you. you most likely hear them but until they come to you and ask you once more, you may say that you didn’t to protect yourself from a lecture of not listening even though it’s clear you did. hope that helped. :)