The cognitive system is organized hierarchically. The most basic perceptual systems are located at the bottom of the hierarchy, and the most complex cogntive (e.g. memory, problem solving) systems are located at the top of the hierarchy.
Information can flow both from the bottom of the system to the top of the system and from the top of the system to the bottom of the system. When information flows from the top of the sytstem to the bottom of the system this is called "top-down processing", which is sometimes known as "theory-driven processing".
The implications of this top to bottom flow of information is that information coming into the system (perceptually) can be influenced by what the individual already knows about the information that is coming into the system (as information about past experiences are stored in the higher levels of the system).
Extreme versions of top-down processing argue that all information coming into the system is affected by what is already known about the world -- the so-called New Look in perception (Bruner, 1957, 1992; Bruner et al., 1951). An alternative version is offered by Jerry Fodor (1983). In his theory of modularity, Fodor argues that top-down processing occurs only in some parts of the cognitive system at certain times. Fodor rejects the idea that all stored information can potentially effect all incoming information.
- Bruner, J. S. (1957). On perceptual readiness. Psychological Review, 64(2), 123-152.
- Bruner, J. (1992). Another look at New Look. American Psychologist, 47(6), 780-783.
- Bruner, J. S., Postman, L., & Rodrigues, J. (1951). Expectation and the perception of color. American Journal of Psychology, 64(2), 216-227.
- Fodor, J.A. (1983). The modularity of mind. Cambridge, MA: MIT Press.