Who is known for explaining behaviors based on a person's internal characteristics or traits?

The correct answer pertains to the concept of personality and how it influences behaviors. Leon Festinger is prominent for his work on cognitive dissonance, which examines how individuals strive for consistency between their beliefs, attitudes, and behaviors. While Festinger is known primarily for his theories on cognitive consistency, his research laid a significant foundation for understanding how internal characteristics, such as beliefs and attitudes, can shape one's actions.

In contrast, the other figures mentioned are credited with different aspects of psychology. Stanley Milgram is best recognized for his obedience studies, which highlight the influence of situational factors on behavior rather than personality traits. Phillip Zimbardo is famous for the Stanford prison experiment, focusing on situational influences on behavior as well. Walter Mischel is noted for his critiques of traditional personality theories and emphasized that behavior is often contingent on situational contexts rather than enduring internal traits.

Thus, Festinger's contributions can be related to an understanding of how internal characteristics or traits affect behavior, aligning him with the explanation of behaviors based on personal traits.