(1) A person's own groups are those with whom he identifies. His in-group includes his family and his college. However, "out groups" are ones with which an individual does not identify. These are outside organizations. An individual may have many outgroups, such as students at another school or employees at a different job. However, he should only have one ingroup. (2) Members of a group share traits that define the group. These shared traits may be physical, such as having red hair; emotional, such as being sad or happy; or cultural, such as eating pork or drinking alcohol. Groups may also share attitudes about certain topics, such as politics or sports teams. (3) It is possible to join a group even though you do not belong to it originally. For example, if someone joins your school's soccer team, they can be included in your in-group even though they do not play soccer. This happens often with social clubs like book clubs or dance classes. (4) It is also possible to become part of a group's out-group. For example, if someone starts using racist remarks on the internet against your school's football team, they have joined their in-group even though they are not affiliated with the team directly. This can happen with hate groups on websites like Twitter or Facebook.