Group behaviour

Group behaviour in sociology refers to the situations where
 * people interact inside small groups, for example to reach or not a consensus and act in a coordinated way. This is the field of group dynamics.
 * large number of people in a given area behave simultaneously in similar way and have a similar goal, that might be different from what they would do individually (herd behaviour).

For example, a large group of people (crowd, mob) is likely to show examples of group behaviour when a group of people, gathered in a given place and time will act in a similar way - for example, they will join a protest or a March, take place in a fight or welcome an idol.

Special forms of large group behaviour are:
 * crowd "hysteria"
 * spectators - when a group of people gathered together on purpose to participate in an event like theatre play, cinema movie, football match, a concert, etc.
 * public - exception to the rule that the group must occupy the same physical place. People watching same channel on television may react in the same way, as they are occupying the same type of place - in front of TV - although they may physically be doing this all over the world

Group behaviour differs from mass actions which refers to people behaving similary on a more global scale (for example, shoppers in different shops), while group behaviour refers usually to people in one place. If the group behaviour is coordinated, then it is called group action.

Swarm intelligence is a special case of group behaviour, referring to the interaction between a group of agents in order to fulfil a given task. This type of group dynamics has received much attention by the soft computing community in the form of the particle swarm optimization family of algorithms.