Sociology is the study of the psychology of groups. Psychology studies individual behavior. There is considerable overlap between individual psychology and group psychology.
Sociology looks at individual behavior as it is influenced by groups. It also studies the behavior of groups as if they were a kind of gestalt of individuals.
Sociology is interested in small groups such as a family unit, a small club, small businesses, and so on.
This discipline also studies large group behavior that would include large movements like the Civil Rights movement, Peace movements, and the Tea Party movement. It might examine political parties and even nations as large groups.
Over the years, sociology has made it abundantly clear that groups, such as mobs, behave very differently than the individuals that make up the group. A sociologist wants to know how groups of people can overcome the psychology of individuals to such an extent that those individuals will behave in ways they would never behave as individuals.
Sociology studies terrorists as groups, seeking to understand how the group affects individual behavior and individual decisions. Military personnel also will behave very differently in a war setting than they would behave in their hometown. It isn’t just a matter of killing the enemy, which is expected of them. It seems that groups can have a morality that is far different than the people who make up that group.
Psychology is mainly focused on individual behavior. Still, psychologists are interested in the dynamics of couples and of family units. School psychologists, who are interested in the behavior of individual students, must also take into account the social situation in which they deal with the child, which is the school setting.
So psychology and sociology are not easily separated. In studying groups of people, sociologists must also have some understanding of the psychology of individuals to understand their interactions in groups.
While psychology studies individual behavior, such behavior seldom exists in a vacuum. Abnormal psychological behavior almost always shows up when individuals interact with other individuals or with groups of individuals. Individual psychological and emotional behavior almost always impacts others.
The tools that are used by the two disciplines must necessarily be different, although, again, these tools will also overlap. Psychology depends largely on self-reports, the patient talking about their personal experiences. The psychologist tries to understand the underlying causes for the patient’s difficulties in coping with life or interacting successfully with others.
The sociologist looks at larger numbers of people and tries to understand the dynamics of their interactions. The sociologist will often use statistics about group behavior as well as administering tests to create their own statistics.
Sociologists study the demographics of specific groups to see how they might behave in the future. This is something that political parties are very interested in. Understanding group psychology is absolutely essential if you want to take the best route to convince a block of people to vote for your candidate.
Politicians cannot be concerned about the psychology of individuals. They must sway large groups of people without alienating other large groups. It is a high wire act and if they make a mistake, they will fall. Misjudging your voting public can end a political career.
Law enforcement looks to sociologists to help them with crowd control. They want to be able to predict how a demonstration is likely to unfold so they can be prepared for the worst.
When the military wants to pacify a population, they’d better know who they are dealing with, especially if that population represents people with a different culture, a different religion, and different ways of seeing and interacting with the world.
It would make no sense to argue that sociology is more important than psychology or vice-versa. They are highly interrelated and both rely heavily on the studies and insights of their colleagues and peers in different disciplines. We are individuals and we are social animals at the same time. To understand ourselves fully, we need to examine both of those aspects in our lives.