An anthropologist is a scientist engaged in the practice of anthropology. Anthropologists study aspects of humans within past and present societies. Anthropologists are trying to understand the "big picture" of what it means to be human for a group of people in the world. Social anthropology, cultural anthropology and philosophical anthropology study the norms, values, and general behavior of societies. Linguistic anthropology studies how language affects social life, while economic anthropology studies human economic behavior. Biological (physical), forensic, and medical anthropology study the biology and evolution of humans and their primate relatives, the application of biological anthropology in a legal setting, and the study of diseases and their impacts on humans over time, respectively.