This lecture discusses the influence of social norms on behavior, focusing on studies related to littering and energy consumption. It covers the concepts of norm salience, anti-littering norms, pro-littering norms, and the impact of feedback on energy-saving behaviors. The presentation also explores the Bobo doll experiment and crowd behavior theories, emphasizing factors like observational learning, attention, retention, reproduction, and motivation. The instructor presents research articles by prominent psychologists such as Robert B. Cialdini and Bandura, providing insights into how social norms shape individual actions and decisions.