Individual behaviour is influenced by the presence of others. For example, studies have found that individuals work harder and faster when others are present (see social facilitation), and that an individual's performance is reduced when others in the situation create distraction or conflict. Groups also influence individual's decision-making processes. These include decisions related to ingroup bias, persuasion (see Asch conformity experiments), obedience (see Milgram Experiment), and groupthink. There are both positive and negative implications of group influence on individual behaviour. This type of influence is often useful in the context of work settings, team sports, and political activism. However, the influence of groups on the individual can also generate extremely negative behaviours, evident in Nazi Germany, the My Lai Massacre, and in the Abu Ghraib prison (also see Abu Ghraib torture and prisoner abuse).