Micro sociologists argue that many of the concepts and institutions that exist in society and that are often treated as social facts are, in reality, social constructs: they have been created by people in society through shared interpretations and assumptions. This is shown in the way that many of these concepts are not universal but are instead understood differently in different societies or at different points in time. For example, childhood is discussed by functionalist sociologists as if it were a social fact but really different societies and different historical eras have completely different ideas of what the word means, including the ages it starts and ends or the rights or privileges that might be expected to go along with that particular time of life.