In psychology, social psychology is the scientific study of how people's thoughts, feelings, and behaviors are influenced by the actual, imagined, or implied presence of others. In this definition, scientific refers to the empirical method of investigation. The terms thoughts, feelings, and behaviors include all psychological variables that are measurable in a human being. The statement that others' presence may be imagined or implied suggests that we are prone to social influence even when no other people are present, such as when watching television, or following internalized cultural norms. Social psychologists typically explain human behavior as a result of the interaction of mental states and immediate social situations.