<P> A self - serving bias is any cognitive or perceptual process that is distorted by the need to maintain and enhance self - esteem , or the tendency to perceive oneself in an overly favorable manner . It is the belief that individuals tend to ascribe success to their own abilities and efforts , but ascribe failure to external factors . When individuals reject the validity of negative feedback , focus on their strengths and achievements but overlook their faults and failures , or take more responsibility for their group 's work than they give to other members , they are protecting their ego from threat and injury . These cognitive and perceptual tendencies perpetuate illusions and error , but they also serve the self 's need for esteem . For example , a student who attributes earning a good grade on an exam to their own intelligence and preparation but attributes earning a poor grade to the teacher 's poor teaching ability or unfair test questions might be exhibiting the self - serving bias . Studies have shown that similar attributions are made in various situations , such as the workplace , interpersonal relationships , sports , and consumer decisions . </P>
when humans make judgment errors that are in favor of the self it is called the
self - serving bias