Skinner's explanation of shaping was this: We first give the bird food when it turns slightly in the direction of the spot from any part of the cage.
By reinforcing a series of successive approximations, we bring a rare response to a very high probability in a short time.
The total act of turning toward the spot from any point in the box, walking toward it, raising the head, and striking the spot may seem to be a functionally coherent unit of behavior; but it is constructed by a continual process of differential reinforcement from undifferentiated behavior, just as the sculptor shapes his figure from a lump of clay.
[3] The trainer repeats this process with the successive approximations getting closer to the target response until the learner achieves the intended behavior.
An oft-cited example is an attempt by Marian and Keller Breland (students of B.F. Skinner) to shape a pig and a raccoon to deposit a coin in a piggy bank, using food as the reinforcer.
After what could be characterized as expressions of frustration, the raccoon resorts to basic “food-getting” behaviors common to its species.
These results show a limitation in the raccoon’s cognitive capacity to even conceive of the possibility that two coins could be exchanged for food, irrespective of existing auto-shaping contingencies.
Autoshaping (sometimes called sign tracking) is any of a variety of experimental procedures used to study classical conditioning.
In its simplest form, autoshaping is very similar to Pavlov's salivary conditioning procedure using dogs.
In Pavlov's best-known procedure, a short audible tone reliably preceded the presentation of food to dogs.
Autoshaping provides an interesting conundrum for B.F. Skinner's assertion that one must employ shaping as a method for teaching a pigeon to peck a key.