Operant Conditioning

We use the term operant (or instrumental) conditioning to describe one type of associative learning in which there is a contingency between a behavior (BH) and the presentation of a biologically significant event (the "reinforcer", outcome or unconditioned stimulus: US). This situation resembles most closely the classic experiments from Skinner, where he trained rats and pigeons to press a lever in order to obtain a food reward ("Skinner-Box", see figure). In such experiments, the subject is able to generate certain motor-output, (e.g. running around, cleaning, resting, pressing the lever). The experimenter chooses a suited output (BH, e.g. pressing the lever) to pair it with a consequence (US, e.g. a food reward). Often a discriminative stimulus (SD, e.g. a light) is present, when the B-US contingency is true. After a training period, the subject will show the conditioned response (CR, e.g. touching the trigger) even in absence of the US, if the BH-US association has been memorized. Such instrumental or operant conditioning is different from Pavlovian or "classical conditioning", where the US presentations are independnt from the behavior of the animal, but instead is contingent upon environmental events. In my general introduction into simple associative learning, you can learn more about the differences between classical and operant conditioning. Once you think you know how operant and classical conditioning work, you can read how "brains as output/input devices" use these forms of associative learning.

Martin Heisenberg and Reinhard Wolf have developed a general model of operant behavior, which joins a description of some more features of operant conditioning.