Commentary: What are behavior systems and what use are they?

The contributions of this symposium on behavior systems are summarized and evaluated by considering two questions: (1) What is a behavior system? (2) What use to the learning theorist are behavior systems? Two examples of behavior systems from the classical ethological literature are compared with the behavior systems discussed in the symposium, and some similarities and differences in the type of analyses used are discussed. Analysis of the pre-organized species-typical behavior systems relevant to the unconditioned stimuli or reinforcers in learning experiments can contribute performance rules and better understanding of the conditions and contents of learning. The organization of behavior systems can also provide important clues to the neural circuitry underlying behavior, and a behavior systems approach can raise novel questions concerning learning and behavioral development. Possible future directions for the behavior systems approach are briefly discussed.