Which person was most interested in studying learned behavior? pysch?

The type of person most interested in studying learned behavior would be a Psychologist.

More specifically a Behavioral Psychologist  - Behaviorists believe that human behavior is shaped by our responses to environmental stimuli, in other words how external events shape our behavior.

Behavioral psychology, is a theory of learning based on the idea that all behaviors are acquired through conditioning. Conditioning occurs through interaction with the environment.

chavez's example shows that nonviolent protest can work well. it shows that one nonviolent man can stop a mob, which proves chavez's point and persuades people to protest nonviolently.