Final answer:
The theory described is the fundamental attribution error, which involves attributing others' behaviors to dispositional factors while attributing our own behaviors to situational factors. This is related to the actor-observer bias and the self-serving bias.
Step-by-step explanation:
The theory that we tend to assign causal explanations for someone's behavior by attributing it to the situation or the person's disposition is known as the fundamental attribution error. This concept falls under the field of social psychology and represents a common bias where observers underestimate situational influences and overestimate dispositional traits as causes for behavior. For example, if Jamie yells after coming home from being laid off, an observer might attribute this to a hostile disposition, overlooking the situational stress of job loss. This is contrasted with our tendency to provide a situational explanation for our own behaviors due to having more information about the context of our actions.
The related idea that we attribute other people's behaviors to internal factors and our own behaviors to situational forces is termed the actor-observer bias. Additionally, the self-serving bias is a tendency to attribute our successes to internal factors and our failures to external ones. The situationist perspective in social psychology emphasizes environmental influence on behavior, while the dispositionist perspective focuses on internal traits and characteristics.