Final answer:
Edwin Sutherland theorized that all behavior, including criminal behavior, is learned through differential association with others, highlighting the importance of social interactions and the environment in the development of criminal behavior.
Step-by-step explanation:
The sociologist who theorized that all behavior, both lawful and criminal, is learned was Edwin Sutherland. Sutherland established the differential association theory, positing that deviant behavior is learned through social interactions and communications within intimate groups. His theory suggests that individuals adopt criminal behavior when they are exposed to more pro-deviant than anti-deviant attitudes, especially if such attitudes are from significant others in their social network. These individuals learn both the techniques and reasons for criminal conduct through their associations.
Sutherland's theory was among the first to challenge the idea that criminal behavior is innate or a product of certain personality traits. Instead, it proposed that all behavior is learned similarly, emphasizing the importance of the environment and peer influences on one's behavior. This marked a shift in criminology and sociology towards understanding crime as a social phenomenon that, like any other behavior, could result from learning processes.