Attribution is a term used in psychology which deals with how individuals perceive the causes of everyday experience, as being either external or internal. Models to explain this process are called attribution theory. Psychological research into attribution began with the work of Fritz Heider in the early 20th century, and the theory was further advanced by Harold Kelley and Bernard Weiner. Heider first introduced the concept of perceived 'locus of causality' to define the perception of one's environment. For instance, an experience may be perceived as being caused by factors outside the person's control (external) or it may be perceived as the person's own doing (internal). These initial perceptions are called attributions. Psychologists use these attributions to better understand an indi