Actor–observer asymmetry

Actor–observer asymmetry (also actor–observer bias) is a bias one makes when forming attributions about the behavior of others or themselves. When people judge their own behavior, they are more likely to attribute their actions to the particular situation than to their personality. However, when an observer is explaining the behavior of another person, they are more likely to attribute this behavior to the actors' personality rather than to situational factors.

Sometimes the actor–observer asymmetry is defined as the fundamental attribution error, which is when people tend to explain behavior on the internal, personal characteristics rather than the external factors or situational influences.

The specific hypothesis of an actor–observer asymmetry in attribution was originally proposed by Edward Jones and Richard Nisbett, where they said that "actors tend to attribute the causes of their behavior to stimuli inherent in the situation, while observers tend to attribute behavior to stable dispositions of the actor". Supported by initial evidence, the hypothesis was long held as firmly established. However, a meta-analysis of all the published tests of the hypothesis between 1971 and 2004 found that there was no actor–observer asymmetry of the sort that had been previously proposed. The author of the study interpreted this result not so much as proof that actors and observers explained behavior exactly the same way but as evidence that the original hypothesis was fundamentally flawed in the way it framed people's explanations of behavior as attributions to either stable dispositions or the situation.

Considerations of actor–observer differences can be found in other disciplines as well, such as philosophy (e.g. privileged access, incorrigibility), management studies, artificial intelligence, semiotics, anthropology, and political science.

Background and initial formulation
The background of this hypothesis was in the 1960s, with social psychology's increasing interest in the cognitive mechanisms by which people make sense of their own and other people's behavior. This interest was instigated by Fritz Heider's book, The Psychology of Interpersonal Relations, and the research in its wake has become known as "attribution research" or "attribution theory."

The specific hypothesis of an "actor–observer asymmetry" was first proposed by social psychologists Jones and Nisbett in 1971. Jones and Nisbett hypothesized that these two roles (actors and observers) produce asymmetric explanations. Their research findings were that "there is pervasive tendency for actors to attribute their actions to situational requirements, whereas observers tend to attribute the same actions to stable personal dispositions". By this theory, a student who studies hard for an exam is likely to explain her own (the actor's) intensive studying by referring to the upcoming difficult exam (a situational factor), whereas other people (the observers) are likely to explain her studying by referring to her dispositions, such as being hardworking or ambitious.

Early evidence
Soon after the publication of the actor–observer hypothesis, numerous research studies tested its validity, most notably the first such test in 1973 by Nisbett et al. The authors found initial evidence for the hypothesis, and so did Storms, who also examined one possible explanation of the hypothesis: actors explain their behaviors because they attend to the situation (not to their own behaviors) whereas observers attend to the actor's behavior (not to the situation). Based largely on this initial supporting evidence, the confidence in the hypothesis became uniformly high.

Recent evidence and refutation
Over 100 studies have been published since 1971 in which the hypothesis was put to further tests (often in the context of testing another hypothesis about causal attributions). Bertram Malle examined this entire literature in a meta-analysis, finding that, across 170 individual tests, the asymmetry practically did not exist. The average effect sizes, computed in several accepted ways, ranged from d = -0.016 to d = 0.095; corrected for publication bias, the average effect size was 0. Under circumscribed conditions (i.e. if the actor was portrayed as highly idiosyncratic, or in negative events), it could sometimes be found, but under other conditions, the opposite was found. The conclusion was that the widely held assumption of an actor–observer asymmetry was false.

Self-serving bias
The actor–observer asymmetry is often confused with the hypothesis of a self-serving bias in attribution — the claim that people choose explanations in a strategic way so as to make themselves appear in a more positive light. The difference between the two hypotheses is that the actor–observer asymmetry is expected to hold for all events and behaviors (whether they are positive or negative) and require a specific comparison between actor explanations and observer explanations. The self-serving bias is often formulated as a complete reversal in actors' and observers' explanation tendencies as a function of positive or negative events. For example, the self-serving bias holds that for positive events, actors will select explanations that refer to their own dispositions, (e.g., "I am smart"); however, for negative events, actors will select explanations that refer to the situation, (e.g., "the test was hard").

Positivity bias
The actor–observer asymmetry can seem similar to the hypothesis of a positivity bias in attribution — the claim that people are biased toward favorable evaluations. This hypothesis states that people will attribute their behavior with positive consequences to internal factors and their behavior with negative consequences to external factors.

Correspondence bias
Observers tend to attribute the actions of others to their future behavior. When someone witnesses another person’s actions, they are likely to attribute those same actions to that person’s future behavior, which is why first impressions are so important. Once an action is observed, it can be difficult for the observer to imagine the actor behaving differently. On the other hand, actors may find it difficult to attribute a single action to their overall behavior. They view themselves as more responsive and in control of situational matters. While actors can attribute their past actions, observers can only attribute the one action they have witnessed to the actor, leading them to attribute dispositional rather than situational factors to the actor’s behavior.