Actions toward and reactions from other individuals constitute social interaction.
Social interaction may take place with someone who is not even physically
present, as in an imaginary conversation. Sociologists study the nature of social
interaction and how relationships can positively or negatively affect our lives.
Even though social life and structure are relatively stable, they are in a constant
process of change. Individuals change over the course of their lives. Societies may
change due to a natural catastrophe, war, a population explosion or a new invention.