Because society is an organized system, it is not surprising that social interaction is patterned. Society is, after all, built on countless interactions among individual human beings, and human beings have the capacity to act with almost infinite variety. In the absence of social patterns, people would indeed find social life confusing. Culture provides guidelines for human behaviour in the form of values and norms.
To illustrate, consider the familiar setting of an American college classroom. Entering the classroom, students could do almost anything — begin to sing or throw a football around the room -- but, guided by the social norms that apply to that setting,
they routinely take their seats, perhaps talking quietly among themselves, and await the arrival of the professor. Even though professors are defined as being in charge of the class, they too are bound by cultural norms, so they begin to teach from a position at the front of the room while facing the class.
Certainly, the behaviour of each student and teacher is partly unique; yet social behaviour in one American classroom is remarkably like that in any other. In spite of personal differences, individuals who enter the classroom behave like «professors» or «students». This fact is clearly evident to people who return, after many years, to a school they once attended. The school is now filled with unfamiliar faces, but the social patterns remain much the same. In other words, even though different people come and go from this setting, the social structure of classroom behaviour persists over time. In the same way, although every family is composed of different individuals, the behaviour of “mothers”, “fathers”, “brothers”, and “sisters” is also largely patterned according to cultural norms.