Ecological psychology is a term claimed by several schools of psychology with the main one involving the work of James J. Gibson and his associates, and another one the work of Roger G. Barker, Herb Wright and associates at the University of Kansas in Lawrence. Whereas Gibsonian psychology is always termed ecological psychology, the work of Barker (and his followers) is also sometimes referred to as environmental psychology. There is some overlap between the two schools, although the Gibsonian approach is more philosophical and deeply reflective on its predecessors in the history of psychology.
Both schools emphasise 'real world' studies of behaviour as opposed to the artificial environment of the laboratory.
Barker's work was based on his empirical work at the Midwest Field Station. He wrote later: "The Midwest Psychological Field Station was established to facilitate the study of human behavior and its environment in situ by bringing to psychological science the kind of opportunity long available to biologists: easy access to phenomena of the science unaltered by the selection and preparation that occur in laboratories." (Barker, 1968). The study of environmental units (behavior settings) grew out of this research. In his classic work "Ecological Psychology" (1968) he argued that human behaviour was radically situated: in other words, you couldn't make predictions about human behaviour unless you know what situation or context or environment the human in question was in. For example, there are certain behaviours appropriate to being in church, attending a lecture, working in a factory etc., and the behaviour of people in these environments is more similar than the behaviour of an individual person in different environments. He has since developed these theories in a number of books and articles.
James J. Gibson, too, stressed the importance of the environment, in particular, the (direct) perception of how the environment of an organism affords various actions to the organism. Thus, an appropriate analysis of the environment was crucial for an explanation of perceptually guided behaviour. He argued that animals and humans stand in a 'systems' or 'ecological' relation to the environment, such that to adequately explain some behaviour it was necessary to study the environment or niche in which the behaviour took place and, especially, the information that 'epistemically connects' the organism to the environment.