This is Skinner’s tale about the discovery of Shaping:
“In 1943 Keller Breland, Norman Guttman, and I were working on a war-time project sponsored by General Mills, Inc. Our laboratory was the top floor of a flour mill in Minneapolis, where we spent a good deal of time waiting for decisions to be made in Washington. All day long, around the mill, wheeled great flocks of pigeons. They were easily snared on the window sills and proved to be an irresistible supply of experimental subjects… This was serious research, but we had our lighter moments. One day we decided to teach a pigeon to bowl. The pigeon was to send a wooden ball down a miniature alley toward a set of toy pins by swiping the ball with a sharp sideward movement of the beak. To condition the response, we put the ball on the floor of an experimental box and prepared to operate the food-magazine as soon as the first swipe occurred. But nothing happened. Though we had all the time in the world, we grew tired of waiting. We decided to reinforce any response which had the slightest resemblance to a swipe—perhaps, at first, merely the behavior of looking at the ball—and then to select responses which more closely approximated the final form. The result amazed us. In a few minutes, the ball was caroming off the walls of the box as if the pigeon had been a champion squash player. The spectacle so impressed Keller Breland that he gave up a promising career in psychology and went into the commercial production of behavior”. (1)
In an article written in 1958 Skinner clarified what was, for him, the key component for effective Shaping:
“In the acquisition of a bowling response in pigeons 3 points are relevant:
– The temporal relationships between behavior and reinforcement are very important.
– Behavior was set up through successive approximations.
– Behavior gradual “shapes up” by “reinforcing crude approximations of the final topography instead of waiting for the complete response”(2).
What, in my opinion, Skinner meant by “shapes” and “raw approximations” is the conditioning of behavior to environmental signals: experimental box, toy pins and ball. Obviously, if I, as a teacher, wait for the exhibition of what I mean being the goal behavior right from the beginning, given the lack of relation (conditioning) between cues and pigeon’s behavior, the animal can never be reinforced and will likely quit the task. But by strengthening the emission of selected behaviors that progressively shape the learner toward the goal behavior, the conditioning will take place and, as Skinner says, our pigeon will prove to be a Bowling Champion.
So it happens with the potter as well: the possibility of the finished shape of the pot is already contained in the clay that is being worked. Indeed it is necessary to precisely shape it. We can also throw the clay on the wheel, but the chances of getting a vessel will be extremely low. The physical characteristics of the clay contain the necessary elements so that it can be modeled. A block of marble or a piece of iron can never be molded – by hand- into a pot. There is not a chance: in their physical characteristics it is not present the possibility of “manual modeling”. As for the clay, or our student – physically – is able to exhibit the behavior or this will never can be taught. Michelangelo could already see the shape of his statues inside the rough blocks of marble: he could try to hit with a hammer randomly the marble trying to create a David, or he could shape it one hit at a time, with approximation -and success- to the final result.
Skinner writes: “A solution is a response that exists in some strength in the repertoire of the individual, if the problem is soluble by him.” In other words: or you can exhibit a given behavior, or you cannot. This skill cannot be taught.
Teaching is to condition the emission of a specific behavior, or of a chain of behaviors, to a given signal. How do we make this happen? If I decide to teach my dog a target nose (the dog touches her nose to the palm of the hand), I have to be sure–or I have to arrange the conditions–that my hand is a clear and new cue with respect to the environment. This is true even if I have to put a piece of food between my fingers to encourage the dog to touch with her nose. Moreover, it is the hand that cues–loud and clear–“Touch me with your nose!”. For this reason the hand should be presented in the same position in order to become a clear signal that affects a specific behavior .
From animals to humans, this pattern does not change, We do, however, have one more tool with humans that we don’t with other animals: the use of language. This gives us a huge advantage in that we can more clearly define the relationship between cue and behavior. In other words, we can specify what to do when a cue is presented. In the following example the cue is the opportunity to shoot for the basket.
THE LESSON IS: “When we shoot the ball, we must have our right hand under the ball with the wrist at eye level. The right forearm is vertical to support the ball. Left hand is resting on the side of the ball to give a guide. The center of the palm of the left hand is resting on the maximum circumference of the ball. the toes look the basket, feet are shoulder-width apart, knees slightly bent and your back is slightly bent forward“.
What is the clear cue to condition this set of behaviors, assuming that the student knows how to do these things? If you are visually impaired, you can not put your toes toward the basket by yourself (the iron can’t be shaped like the clay). The cue is the opportunity to shoot the ball and not the basket itself. We shoot when we’re reasonably sure to have the chance to score… This involves, at least: being close enough to the basket and having time for aiming the basket. This opportunity is the cue activating the behaviors chain. Obviously we have to teach (to shape) how to put together a whole sequence so that it becomes fluent: performed automatically when the cue occurs. We need to avoid overloading the working memory of the student who would otherwise not be able to hold together all the instructions in his or her memory. Michelangelo created his works one step at a time. Then we will choose the first component to be conditioned to “shoot for the basket .”
THE INSTRUCTIONS ARE: “When we shoot the ball, we focus on the basket. The easiest way to do this is to point your feet toward the basket. Start from the center, go to the cones (placed on the floor around the basket to indicate where to throw) and shoot. Feet are pointed toward the basket. “
We have reduced the amount of information. If we deliver too many steps, at least some get lost in the working memory and the behaviors that will be exhibited in the presence of the cue will be poor in reference to our goals. Therefore we choose a single point of attention, just one behavior to start to signal “shoot for the basket.”
THE TAGPOINT IS: “Feet to the basket”.
The sound of the marker, the click or “TAG,” indicates the learner’s success and affects the behavior, further strengthening it: when there is a basket and you have the chance to score, just put the feet toward the basket. Once we have this behavior fluent we can, gradually, add the following steps. Finally, the opportunity to shoot for the basket will determine the position of the feet that will then effect the shoulders, the legs, and so on.
Let me be crystal clear: I have not taught to point the feet toward the basket. What I have taught is that at the cue: “shoot for the basket” what has the greatest chance of being reinforced (because it increases the chances of scoring) is if the feet point the basket. In Skinner ‘s example of shaping the pigeon: the pigeon knows how to hit a ball with its beak. What Skinner has taught us is that, given the presence of the ball and skittles (cues) that will be reinforced (or will have the opportunity to be reinforced) will be: ” Hit the ball in a certain and specific direction”.
(1) PETERSON G.B., A day of Great illumination – Skinner’s discovery of Shaping, ” Journal Of The Experimental Analysis Of Behavior”,82, (November 2004), p. 317–328. Breland ended being quite famous (and rich) training animals for show, movies and TV series.
(2) SKINNER B.F., Reinforcement today, “American Psychologist”,13 (1958), p 94-99