Collective behaviour refers to group behaviour that is not guided by usual social norms. It is relatively unorganized and unpredictable. Some key characteristics of collective behaviour include being temporary, unplanned, lacking rules or procedures, and prone to rumours and misinformation. Examples include panic behaviour during emergencies. Theories of collective behaviour aim to explain how it arises from conditions like structural strains, the spread of general beliefs, and precipitating events. Crowd behaviour is a type of collective behaviour where people in close proximity develop a shared focus and their individual identities feel anonymous within the group.