A production system is program that comprises a series of conditional statements that specify what action is to be taken under certain circumstances. These 'If ... then ...' statements are known as productions. For example, a production system for a cricket batsman may comprise a series of productions such as the following.
- ball outside offstump ------> no action
- ball pitched on wicket and good length ------> forward defensive stroke
- ball pitched short on leg side and fast------> duck
- ball pitched short on leg side and slow------> hook
Information from the environment is matched against all productions and if the condition on the left of the arrow is true then then action on the right will be performed. However, as systems become more complex many productions may be triggered and the system will face a scheduling problem. The system must contain a production that will determine which production of the many possible will be fired. Common conflict scheduling productions are; order in the production system, specificity, refractoriness and recency.
Production systems were one of the first attempts to model cognitive behaviour and form the basis of many existing models of cognition.
- Newell, A., & Simon, H.A. (1972). Human problem solving. Englewood Cliffs, NJ: Prentice-Hall.