Final answer:
Albert Bandura proposed the concept of observational learning, where learning can take place by watching others without the need for direct reinforcement.
Step-by-step explanation:
The psychologist who would argue that learning can take place when someone watches another person and performs that behavior even when not reinforced is Albert Bandura. Bandura's key contribution to learning theory was the concept of observational learning.
Unlike strict behaviorists such as B. F. Skinner or John Watson, Bandura believed that learning involves cognitive processes and that people can learn by observing and modeling the behavior of others, even in the absence of direct reinforcement or punishment. According to Bandura, this is because internal mental states must also play a role in learning processes.