In any Society, through interaction amongs differents individuals, people identify themselves in a certain group. For instance, in a classroom, usually each student has an unique student number, by accepting such a number, every student has a valid identification in the class and thus can conduct daily learning activities.However, that doesn't mean we at the same time define ourselves or find our existence through identificaition with social groups, on the contrary, we can easily lose ourselves when we get recognition from other group memebers. Individual has their own traits and have the rights to get respect whether they identify with a special social group or they just choose to stay alone. The existence of human being doesn't need others to prove it, It's in fact a basic right of every people.
With the development of human society, people are involved into more and more social events and individuals are interdependent with each other.
Consciously or unconsciously, people always place themselves into a special group which is called "external environment" to some philosophers to compare with "internal environment" -- self consciousness.
A for the characteristics of humans, every single individual is unique, their traits are formed by their characters, their outlook, their sex, their interests, their talking way, some are learned, some are innated. Whether they belong to social groups or not, people have their own unique position in others' eyes. In a given group, members in it are often very different with each other. For example, in our teachers, some are very strict and serious, never smile even there is no test, there is no class while some teachers are kind enough, have little homeworks, considerable, always prepare to answer students' questions... They are in the same groups but behave in much dissimilar ways. They define their own roles...