Final answer:
B.F. Skinner is the psychologist most closely associated with the study of operant conditioning, using the Skinner box in his experiments to explore how reinforcement and punishment affect behavior.
Step-by-step explanation:
The psychologist most closely associated with the study of operant conditioning is B.F. Skinner. Working with the law of effect, Skinner conducted scientific experiments on animals to understand how organisms learn through operant conditioning. A key tool in these experiments was the Skinner box, an operant conditioning chamber that allowed for the systematic study of behavior modification through reinforcement and punishment. Skinner's work emphasized that behavior could be shaped and influenced by its consequences, and his findings have had a profound impact on psychology, particularly in the areas of behavior modification and applied behavior analysis.