People seek to understand the causes of behavior through attribution theory, which examines how people make causal explanations for their own and others' actions. There are two types of attributions - internal, which attributes behavior to internal factors like ability or personality, and external, which attributes behavior to outside influences. When making judgments about others, people tend to underestimate external influences and overestimate internal influences, known as the fundamental attribution error, and they are also prone to the self-serving bias by taking credit for successes but blaming failures on external factors.