 However, if another person scores poorly on a test, the person will attribute the results to internal factors such as laziness and inattentiveness in classes.The theory of the actor-observer bias was first developed by E. Jones and R. Nisbett in 1971, whose explanation for the effect was that when we observe other people, we tend to focus on the person, whereas when we are actors, our attention is focused towards situational factors.The actor/observer bias is used less frequently with people one knows well such as friends and family since one knows how his/her close friends and family will behave in certain situation, leading him/her to think more about the external factors rather than internal factors.