A major strength of anthropology is its scope: anthropologists study human evolution and variation, both across and within societies over time. Given this broad scope, anthropologists frequently use inter-disciplinary approaches to study interactions between biological processes and environmental influences. IAST anthropologists in particular use a scientific perspective to inform our understanding of human behavior, psychology and health. IAST anthropologists focus their research on ecological, bio-behavioral and demographic aspects of human variation within the frameworks of human adaptability and evolution. Active research areas include the following: human biology, life history theory, behavioral ecology, human development and plasticity, cultural evolution, aging, demography, diet and nutrition, global health, evolutionary medicine and human genetics. IAST anthropologists employ a wide range of methods common to the life, social and behavioral sciences, including observational fieldwork, biomedical surveillance, field and laboratory experiments, analysis of secondary datasets, and theoretical modeling.