Thomas Gilovich said this quote

When examining evidence relevant to a given belief, people are inclined to see what they expect to see, and conclude what they expect to conclude. Information that is consistent with our pre-existing beliefs is often accepted at face value, whereas evidence that contradicts them is critically scrutinized and discounted. Our beliefs may thus be less responsive than they should to the implications of new information

~ Thomas Gilovich

People will always prefer black-and-white over shades of grey, and so there will always be the temptation to hold overly-simplified beliefs and to hold them with excessive confidence

~ Thomas Gilovich

What we believe is heavily influenced by what we think others believe

~ Thomas Gilovich

it seems that once again people engage in a search for evidence that is biased toward confirmation. Asked to assess the similarity of two entities, people pay more attention to the ways in which they are similar than to the ways in which they differ. Asked to assess dissimilarity, they become more concerned with differences than with similarities. In other words, when testing a hypothesis of similarity, people look for evidence of similarity rather than dissimilarity, and when testing a hypothesis of dissimilarity, they do the opposite. The relationship one perceives between two entities, then, can vary with the precise form of the question that is asked

~ Thomas Gilovich