Definition for Actor-observer effect
From Biology Forums Dictionary
The actor-observer effect is based on our tendency to attribute our own behavior to situational causes (causes that are external to the individual) and on our tendency to attribute other people's behavior to internal (dispositional) causes. The result is that if two people engage in the same behavior, each will see the reason for his or her own behavior as being something in the environment, but see the other person's behavior as reflecting something within the self.