Psychological Laboratory's Answer To a Teacher Shortage: Machines

"There are more people in the world than ever before, and a far greater part of them want an education," writes Professor B. F. Skinner, in a recent issue of Science magazine. "The demand cannot be met simply by building more schools and training more teachers. Education must become more efficient."

In a low-ceilinged, fluorescent-lit basement room in Sever Hall stands a row of machines which may someday supply such efficiency. They are updated models, constructed by Professor Skinner, of the teaching machines devised in the '20's by the inventor Sidney L. Pressey. The teaching machines facilitate automatic testing of information and intelligence.

These contraptions are now under study and development by members of the Psychological Laboratory in Memorial Hall. The work has been financed by two annual grants from the Fund For the Advancement of Education, and its purpose is an "investigation of the place of teaching machines in the employment of college-level teaching resources."

Professional adversary of Dr. Henry A. Murray and his doctrine of Jungian humanism, the Psychological Labs operate under the contention that the simple mechanical methods of stimulus and response--successful in the study and control of lower organisms--may also be applied successfully to men. The teaching machines, in their manner of operation and in their intent to remove some of the human contact between teacher and student, definitely lie in the Cambridge Street camp.

The intention of the research, as Professor Skinner has stated in his report to the Fund, is on "controlling the variables of which learning is a function." By setting up suitable "contingencies of reinforcement," Skinner says, the particular modes of behavior can be directed by the particular type of stimuli. The consequent behavior proves to be predictable over long stretches of time.

Machines Guide Responses

The student is "taught" in the sense that his responses to certain problems and situations are guided and formed by the machines. The actual machines are simple. They consist of a small control box, something like the transformer of a toy electric railroad, with buttons that advance, hold or return verbal information. This information, called the program, is printed on disks, tapes or cards. One frame, or question-answer unit, appears to the student at a time,

In one rudimentary version of the machine, the student answers by manipulating printed figures or letters. His arrangement of the figures and letters is compared by the machine with the correct answer, in code. If machine answer and student answer are congruent, the machine automatically proceeds to the next frame. If they do not agree, the student's answer is blanked out and he must answer again; the machine will not proceed until the right answer has been set down.

Obviously such a process lacks the flexibility needed for more complex problems, where no absolutes of yes and no are possible; the simpler machines are suitable for teaching spelling and arithmetic in the primary grades, and are now being tested in these areas.

A more subtle and complex model makes is possible for the student to compare his answers with the printed correct response which the machine shows to him. In this type the information is printed in thirty radial frames on a paper disk. The disk is inserted, and once locked inside cannot be removed for examination (or cheating) until all the answers have been completed. The portion of the frame in which the correct answer is written is concealed until the student writes his own answer on a paper strip, visible through another opening.

Correct Answer Revealed

When he has answered, he moves a lever and the cover concealing the answer falls away. If his answer is the right one and corresponds, he moves the lever horizontally. In doing this he punches a hole in his answer strip, ineradicably noting that he thought his written answer correct. This same motion advances the machine to the next frame, and at the same time changes the position of the disk so that the correctly answered frame will not appear again if the student goes more than one full circle on the disk. Even if the answer is incorrect, the lever advances the machine to a consequent frame. When the disk spins without a step, all questions have been answered and the assignment is done.

The Programming of the material seems to be much more complicated than the construction of the machine. Through programming, "specific forms of behavior are to be evoked and, through differential reinforcement, brought under the control of specific stimuli." It is the step-by-step organization of the knowledge to be inculcated; and the frames are chosen and arranged in the way which will fully exploit the advantages of "immediate feedback," or direct determination of an answer's correctness or incorrectness.

Professor Skinner makes an example of the rudimentary type machine in teaching a third or fourth grade pupil to spell the word manufacture. "The six frames are presented in order, and the pupil moves sliders to expose letters in the open squares."

1. MANUFACTURE means to make or build. Chair factories manufacture chairs. Copy the word here:

----------------------

2. Part of the word is like part of the word factory. Both parts come from an old word meaning make or build.

man -- fact -- re

3. Part of the word is like part of the word manual. Both parts come from an old word for hand. Many things used to be made by hand.

--------facture

4. The same letter goes in both spaces:

m -- nuf -- cture

5. The same letter goes in both spaces:

man -- fact -- re

6. Chair factories:

---------------------- chairs.

In the first frame the word to be learned appears along with a definition and an example. When he copies it correctly, the second frame appears. Now he has to be selective in his copying; He must see the common root of "fact" in "manufacture" and "factory." This helps him to acquire what Professor Skinner calls an "atomic verbal operant." In the third frame another root must be perceived. In four and five the student must put down letters without assistance. In frame six the student fills in the whole word to make the sentence which he knows from the first example.

As Professor Skinner says, "Even a poor student is likely to do this correctly because he has just composed or completed the word five times, he made two important root-responses, and has learned that two letters occur in word twice. He has probably learned to spell the word without mistakes."

This sequence gives an example of the manner in which the student's mental responses are guided and aimed at a particular end in each "lesson." The more cogently selected and clearly connected each frame in the series is, the more effective the program of the machine in instilling the intended knowledge

Using the more complex machine for high-school and college level often requires a system called "vanishing." In learning a poem, for example, first certain insignificant letters are omitted, then important letters, then unimportant words, then more important words. After that a whole line is dropped out, then increasing numbers of lines, and in a surprisingly short time the student is able to repeat the whole verse without having made a wrong response.

The same method of "vanishing" can be used to enable a student to talk in technical or scientific terms about a certain subject. Professor Skinner uses as an example the vocabulary transformation from lay to technical on the emission of light from an incandescent source:

1. The important parts of a flashlight are the battery and the bulb. When we "turn on" a flashlight, we close a switch which connects the battery with the (bulb).

2. When we turn on a flashlight, an electric current flows through the fine wire in the (bulb) and causes it to grow hot.

3. When the hot wire glows brightly, we say that it gives off or sends out heat and (light).

4. The fine wire in the bulb is called a filament. The bulb "lights up" when the filament is heated by the passage of an (electric) current.

5. When a weak battery produces little current, the fine wire, or (filament) does not get very hot.

6. A filament which is less hot sends out or gives off (less) light.

7. "Emit" means "send out." The amount of light sent out, or "emitted," by a filament depends on how (hot) the filament is.

8. The higher the temperature of the filament the (brighter, stronger) the light emitted by it.

9. If a flashlight battery is weak, the (filament) in the bulb may still glow, but with only a dull red color.

10. The light from a very hot filament is colored yellow or white. The light from a filament which is not very hot is colored (red).

11. A blacksmith or other metal worker sometimes makes sure that a bar of iron is heated to a "cherry red" before hammering it into shape. He uses the (color) of the light emitted by the bar to tell how hot it is.

12. Both the color and the amount of light depend on the (temperature) of the emitting filament or bar.

13. An object which emits light because it is hot is called "incandescent." A flashlight bulb is an incandescent source of (light.)

14. A neon tube emits light but remains cool. It is, therefore, not an incandescent (source) of light.

This process accomplishes a gradual and comprehensive replacement of the indistinct general terms by the technical ones. "Filament" replaces "fine wire"; "emit" takes the place of "glow" and "give off light", and then the word "emit" is inflected in different ways for greater familiarity with terms.

Such a program must be very carefully worked out to avoid ambiguity and to escape incorrect but justifiable answers. For example in number three, the words heat and are necessary to make heat impossible for the answer. It is probably harder to compose such a program than it is to cover the same material in a textbook passage. The machine material must be clear and self-contained, because the machine is the only source, and cannot clarify itself as a teacher can.

"Textbooks," Skinner remarked, "are of little help in preparing a program. They are usually not logical or developmental arrangements of material but strategems which the authors have found successful under existing classroom conditions. The examples they give are more often chosen to hold the student's interest than to clarify terms and principles. In composing material for the machine, the programmer may go directly to the point.

Actually, of course, it is wrong to say that the machine does any teaching. It just presents the material in a logical way, conveys knowledge from the composer of the program to the student. Of course it is infinitely more efficient than a real teacher, since the number of students to whom it can convey this information is virtually limitless.

Professor Skinner says that in many ways his teaching machines are like individual tutors, and indeed the machines seem more accurate than many of its rivals in Cambridge. He points out that there is a continual interchange between the program and the student, and that since the student is always active, manipulating the machine, he avoids the stupor of textbook-reading or lecture-drowze. Skinner points out that, "like a good tutor, the machine insists that a given point be thoroughly understood, either frame by frame or set, before the student moves on." And perhaps most importantly, the machine, like a good tutor, substantiates and corroborates right answers and quickly points out and corrects wrong ones--"using this immediate feedback not only to shape his behavior most efficiently but to maintain it in strength in a manner which the layman would describe as 'holding the student's interest.'"

The greatest virtue of the machines is that, by all the admittedly scanty information on their effectiveness, they seem to put knowledge into a student's head and to make the knowledge stick with much less trouble and time than either books, audiovisual aids, or lectures. In Nat Sci 114 last year, in which forty-eight of the machines' disks replaced the textbooks, the average time spent at the machines to complete the forty-eight disks (equivalent to nearly a whole semester's reading) was about fourteen and a half hours. Comprehension did not suffer. Eventually the text was read too, for comparative purposes. To the question, "In comparing work on the machine with studying the text, I felt that with the same time and effort," thirty-two per cent of the students said that they had learned "much more" on the machine, and forty-six per cent said they learned "somewhat more" on the machine. Seventy-seven per cent of the students said, "I would have got less out of the course if machines had not been used."

The real asset of teaching machines, of course, and very likely the reason so much money is being spent now on their research and development, is the terrific dearth of teachers in this country. If teaching machines could be run off assembly lines as just another gadget and someday became as common as television sets, the few teachers there are could be liberated from the more ponderous tasks of mechanical instruction they now have to perform, and the dilemma of the teacher shortage could be substantially diminished, if not wiped out entirely.

Problems Presented

The time is not so far off as one might think, but the idea of machines for teaching brings up many problems not noticed at first glance. Grading systems would probably have to be greatly revised; the entire concept of education by coercion, motivation, threat and sweat would have to be reexamined; and the application of scientific principles to secondary education would have to be considered. Professor Skinner himself has said: "In the light of our present knowledge a school system must be called a failure if it cannot induce students to learn except by threatening them not to learn." A study of education within the structure of the modern science of behavior does indeed have broad implications.

Harbinger of New World

Whether or not the teaching machines, in a generation or so, will become a major weapon in winning the battle for western technological supremacy; whether or not they will someday help equalize the supply of teachers with the demand; certainly that row of ten silent machines in Sever Hall is a harbinger of a nervous and not too brave new world.Pictures courteous of Psychological LaboratoriesThe Self-Instruction Room in Sever Hall. There are ten booths holding the teaching machines, some outfitted with indexing phonographs.