The observation of human and animal behavior has been referred to as the sine qua non of science, and indeed, any research concerning behavior ultimately is based on observation. A more specific term, naturalistic observation, traditionally has referred to a set of research methods wherein the emphasis is on capturing the dynamic or temporal nature of behavior in the environment where it naturally occurs, rather than in a laboratory where it is experimentally induced or manipulated. What is unique about the more general notion of observational research, however, and what has made it so valuable to science is the fact that the process of direct systematic observation (that is, the what, when, where, and how of observation) can be controlled to varying degrees, as necessary, ...