The size and dynamic of a group greatly affects how members act. Primary groups rarely have formal leaders, although there can be informal leadership. Groups generally are considered large when there are too many members for a simultaneous discussion. In secondary groups there are two types of leadership functions, with expressive leaders focused on emotional health and wellness, and instrumental leaders more focused on results. Further, there are different leadership styles: democratic leaders, authoritarian leaders, and laissez-faire leaders.
Within a group, conformity is the extent to which people want to go along with the norm. A number of experiments have illustrated how strong the drive to conform can be. It is worth considering real-life examples of how conformity and obedience can lead people to ethically and morally suspect acts.