information:highlighting, information:filtering
Questions about the law of effect

A number of observations seem to show that operant behavior can be established without reinforcement in the sense defined above. Most cited is the phenomenon of autoshaping (sometimes called "sign tracking"), in which a stimulus is repeatedly followed by reinforcement, and in consequence the animal begins to respond to the stimulus. For example, a response key is lighted and then food is presented. When this is repeated a few times a pigeon subject begins to peck the key even though food comes whether the bird pecks or not. Similarly, rats begin to handle small objects, such as a lever, when food is presented nearby. Strikingly, pigeons and rats persist in this behavior even when pecking the key or pressing the lever leads to less food (omission training). Another apparent operant behavior that appears without reinforcement is contrafreeloading.