Social science is a group of academic disciplines that study human behavior and how people interact with one another. It is a branch of science that is devoted to the study of societies and the relationships among individuals within those societies. Social science is a relatively new field of scientific study that rose to prominence in the 20th century. The branches of social science include anthropology, economics, political science, psychology, and sociology. Social scientists study how societies work, exploring everything from the triggers of economic growth and the causes of unemployment to what makes people happy. Their findings inform public policies, education programs, urban design, marketing strategies, and many other endeavors. Social science differs from natural science in that it examines the human, constructed world rather than the physical world. Social science comprises 16 major disciplines and many sub-disciplines and specialisms. Some examples of social sciences include anthropology, economics, geography, political science, psychology, and sociology.