In contrast, observers tend to provide more dispositional explanations for a friend’s behavior ( Figure). This supports the idea that actors tend to provide few internal explanations but many situational explanations for their own behavior. In contrast, when speculating why a male friend likes his girlfriend, participants were equally likely to give dispositional and external explanations. The participants’ explanations rarely included causes internal to themselves, such as dispositional traits (for example, “I need companionship.”).

When asked why participants liked their own girlfriend, participants focused on internal, dispositional qualities of their girlfriends (for example, her pleasant personality). One study on the actor-observer bias investigated reasons male participants gave for why they liked their girlfriend (Nisbett et al., 1973). However as observers, we have less information available therefore, we tend to default to a dispositionist perspective.

As actors of behavior, we have more information available to explain our own behavior. The actor-observer bias is the phenomenon of attributing other people’s behavior to internal factors (fundamental attribution error) while attributing our own behavior to situational forces (Jones & Nisbett, 1971 Nisbett, Caputo, Legant, & Marecek, 1973 Choi & Nisbett, 1998). If you came home from school or work angry and yelled at your dog or a loved one, what would your explanation be? You might say you were very tired or feeling unwell and needed quiet time-a situational explanation. When it comes to explaining our own behaviors, however, we have much more information available to us. Due to this lack of information we have a tendency to assume the behavior is due to a dispositional, or internal, factor.

The only information we might have is what is observable. Why do you think we underestimate the influence of the situation on the behaviors of others? One reason is that we often don’t have all the information we need to make a situational explanation for another person’s behavior. So a naïve observer would tend to attribute Greg’s hostile behavior to Greg’s disposition rather than to the true, situational cause. Returning to our earlier example, Greg knew that he lost his job, but an observer would not know.

Actor vs observer bias