Collective behaviors refer to the actions and reactions of a group of individuals who come together in response to a common stimulus or situation. These behaviors can be seen in various contexts, such as in crowds, social movements, or animal groups. Examples include crowd behavior during a concert or flocking in birds, where individuals act in unison without a central leader. These behaviors often arise from shared emotions, goals, or environmental factors. They can lead to phenomena like social contagion, where feelings or actions spread rapidly among people, or swarm intelligence, where groups make decisions collectively, often resulting in more effective outcomes than individuals acting alone.