It is widely said that every person on this planet is different in terms of skills, intellect, skin colour,etc. SO is the case with societies. As a human we differentiate with other human beings in terms of religion and rituals. Humans have invented the rituals , which they follow adherently, to differentiate themselves from other humans. There are billions of people on this earth and every religious sect or every society have its own culture and rituals.Without these rituals we are practically same with a body , brain and every thing that makes us humans.Only varied rituals and culture define us and separate us from fellow humans.This can be explained by studying various religions. A person may be a Christian, Islamic, hindu or belong to some other religion and all these have different rituals. Christians have many rituals during their marriage ceremonies , they get married in a church or some divine place and exchange vows , cut cake and bride throws flowers on someone who is not married. Hindus have different rituals during their marriage. They take vows by circling around a fire and groom put a necklace(called mangal sootra) around brides neck as a ritual. Whereas muslims say "I accpet" three times during thier marriage ceremonies. Purpose of marriage is to take vows but the different rituals that one follow make these marriage entirely different from others.Also we can take the case of child birth. In India there are hundereds of religions and culture and people of every culture have there their own rituals to welcome the new born. Some hindu groups do a ritual where they pray to the God for the well-being of the child. Some might do it on sixth day of the child birth or some might do it after forty days. Some people remove their child's hair after year or so or some do it when child is 3 years old. All these people belong to same religion but only these rituals and ceremonies makes them different in the society. Rituals and ceremonies are not programmed in our brain. These were invented and later refined by us only.I think people with common beliefs invented rituals pertaining to an important events like marriage or child birth and to differentiate with other people they did some changes.Every ritual with a subtle refinement becomes different from the other.These subtilities makes these rituals different and help a person define itself socially and culturally.