Foundations Of Cognitive Science


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. Each production has a condition and an action. If the condition is found to be true by the system then the action will be performed. For example, a production system for a thermostat may contain a production such as the following.

  1. temperature > 70 and temperature < 72 ----> stop

Information from the environment is compared to the conditions of the production. If the condition to the left of the arrow is true then the process to the right of the arrow will be performed. In the above example will the thermostat will stop as long as the temperature remains within the range of 70 and 72 degrees. If the temperature is outside that range then a different production will be activated and the system will change behaviour.


  1. Newell, A., & Simon, H.A. (1972). Human problem solving. Englewood Cliffs, NJ: Prentice-Hall.