Group behavior in sociology refers to the situations where people interact in large or small groups. The fiel of group dynamics deals with small groups that may reach consensus and act in a coordinated way. Groups of a large number of people in a given area may act simultaneously to achieve a goal that differs from what individuals would do acting alone (herd behaviour). A large group (a crowd or mob) is likely to show examples of group behaviour when people gathered in a given place and time act in a similar way—for example, joining a protest or march, participating in a fight or acting patriotically.