One of the sociological concepts that I have always found interesting in the courses I have taken is social stratification. In societies, an individual's access to wealth and income greatly influences their access to resources and opportunities. Those opportunities can be further impacted by factors such as an individual's race, gender, and religion. Those with the most wealth, and therefore the most opportunities, in American society are known as belonging to the upper class. Those who have the least wealth and income belong to the lower class, and there is a middle class who falls between those two extremes. Within this concept, we also discuss an individual's social mobility and the inflexible systems of stratification within some societies (such as those structured by caste systems).
Sociological concepts also include an examination of the way people function together in a society. Thus, it is common to examine the norms and values of any group and how people are expected to behave in within the group. Socialization is commonly studied as a means to determine how individuals are taught the behavioral expectations of a society.
An individual's social roles and social identity are also commonly studied. This is an examination of how an individual incorporates a variety of expectations which are determined by society and manipulates their behavior to meet those varied expectations. Thus, a 40-year-old woman may identify with all of the following social roles: wife, mother, engineer, sister, daughter, friend, community activist, volunteer, and politician.
Another interesting sociological concept is the idea of a self-fulfilling prophecy. This concept relies on how societies label individuals, sometimes from incredibly young ages. This concept states that sometimes people act as they are expected to act—as determined by a label—and the label thus becomes reality. For example, a child who is constantly labeled "shy" in front of others may hesitate to engage socially, and eventually this lack of interaction causes them to become a "shy," or withdrawn, adult. Conversely, if a child is constantly labeled "brave," they might actively choose actions requiring more courage, and repeating those behaviors helps him grow into a more confident and brave adult.
There are many topics to explore in the studies of how societies influence people and how people influence their societies.