Every group member must complete their task in order for the group task to be completed. An example of this would be an assembly line, in which each worker performs tasks that together build a completed car. Members meet to determine the best alternative for a problem or issue. Group members must choose one correct answer from all alternatives. There is no one correct answer for a decision-making group.
Some groups form spontaneously, such as a group of friends.
Other groups are contrived, that is, they are formed for a specific purpose. Organized clubs, social groups, or committees are contrived groups.