Teaching machines - American Chemical Society

Teaching. Machines. Jesse H. Day. Ohio University. Athens, Ohio. The most effective teaching situation ... good teacher and the largest possible numbe...
0 downloads 0 Views 5MB Size
Jesse H. Day

Ohio University Athens, Ohio

Teaching Machines

The most effective teaching situation consists of one good teacher and one student in active two-way discussion; the most e f i c i a t situation consists of one good teacher and the largest possible number of students. Used in this way effective and efbient are not only not synonymous, they highlight the urgent problems posed by mushrooming enrollments. Education by television helps solve the problem of efficiency by presenting the best lecturer to the greatest number of students, and the same sort of solution is offered by movies. The element of effectiveness missing from the formal lecture or its equivalent is, of course, the opportunity of the student to discuss, to ask questions; he may he lost through the main part of t,he presentation due to his failure to understand a previously-presented idea. Later quiz sections make up this deficiency only in part, since lapse of time obscures either the nature of the uncertainty or even the uncertainty itself, or the student may be embarrassed to ask in the presence of his peers. The teaching machine provides for still another approach; individual tutorial instruction for each of an indefinitely large number of students. The novelty of this approach is that the effectiveness of instruction is improved in addition to the efficiency. The psychological laws of learning are used to an extent not normally possible in the structure of the usual classroom situation. The student is continuously active, he has immediate confirmation of his correct conclusions (reinforcement), and he is never lost since he proceeds to new information only as the preliminary ideas are mastered. A battery of fairly complex teaching machines might cost as much as a modest television installation, but a simple device for presenting a sequential program can be made from a file folder, and a "scrambled-hook" program from duplicated sheets stapled together. What I s a Teaching Machine?

A teaching machine is a mechanical device designed to present a particular body of information to the stndent. The machine may be very simple or as complex as electronic engineering ingenuity and financial resources can make it. Teaching maehines differ from all other teaehing devices and aids i n that they require the active participatia of the learner at a e r y step. This is the whole point; the learner cannot go from step one to step two without active thought and response. The teaching machine is a laboratory for Presented before the Division of Chemical Education at the 135th meeting of the American Chemical Society, Boston, Mass., April, 1959.

the learning processlaboratory in which the essential equipment is ideas, and the experiment is the manipulation of those ideas. The best features of tutorial interchange are approached; student response, knowledge of results, constant interaction between the student and the simulated tutor. While there is an intinite variety of actual machines, they all function in .the same general way.' The learner is first presented with some idea and asked to reach a conclusion about the idea. He may then construct his answer and compare it with other machine information for correctness; or he may choose one of several answers pre-ented by the machine. When the answer is chosen, the machine presents an opportunity to discover whether the answer is correct or not; and in some types of machines not only that the anewer is correct, but why it is correct, and if it is wrong, why it is wrong. The learner persists until he gets a right answer, and then the machine uses the new information added to the original information to elicit a response to a new and more complex situation. In this fashion the student proceeds through the machine a t his own rate and without supervision until he has completed the unit of material for which the machine was programmed. The machme should also make it impossible for the student to fudge by peeking ahead, and should provide a method for scoring. It is essential that the topic to be taught be carefully organized in logical progression, each step building on and adding to the preceding knowledge. The steps must be small, so small that the student will succeed very often and fail only rarely. Not only does this render the student's progress possible, i t guarantees success. Typically the initial successes draw the student on to try the next step; interest and motivation are "built-in" by the student's own activity. It is difficult to describe adequately the motivating effect, but typical experience shows that the problem is not to get the student to keep working, but conversely, to get him to stop! U. S. Patent 52,758, was issued February 20,1866: to Halcyon Skinner for a mechanical device for teaching spelling. It consisted of a. roll of pictures and a. set of letter keys for spelling the name of eaoh abject piotured. This is not a "teaching machine" in the sense used in this article, hut it is a very early example of mechanization of a learning situation. A variety of teaching machines has been placed on the market since this paper was written. On view at the American Psychological Association meeting this September were several models by Western Design and some by Rheem Mfg. Co. Among others expected to enter the field shortly are Specialty Products, Graphic Calculator, and Hamilton Aasooiates. The only programs yet offered are by National Teaching Machines in algebra, with other subjects to follow. Volume 36, Number 12, December 1 9 5 9



Figure. i and 2. The machine shown i s being v i e d to teach par, ot o course in Natural Siience a t n a r v a r d U n i " r r , i r y , ' , n un crpcrirnsn+ i u r d u i l f d t-, Skinner, Holland, and colleagues. The machine progrom, which in this ~onsirtrof incomplete senfencer, is printed rodiolly an o poper disc. The disc is mounted in the machine, which exposer one item a t o time through the central rlot. The student reads the incomplete sentence, then writer his rerponre on o roll o f p a p e r through the rlof a t the right. Moving the lever upward roll. the on9wer up under o piece of plastic ro it con b e r e a d but not changed, and a t the r o m e time the correct rerponre ir revealed in the upper right-hand corner o f the program rlot. I f the student'l o n w e r is correct, the lever is moved to the right, which punches o hole in the answer poper and advances the program to the next item. A second time around, the machine rtapt only at fhe items missed the first time. The punch holes in the t o p e also give a method of rating the student performonce.

The Skinner Sequential Program

It is a cardinal point of the program developed by Skinner that the student be required to construct his response; for example, to write out the correct word or phrase. Not only is a correct overt response elicited, but a pedagogical pitfall is avoided; a multiple choice question must present a number of plausible wrong responses, and Skinner believes it is a mistake to suggest a wrong answer to a student. The machine present,ly being used by Skinner is shown in Figures 1 and 2. Chemical Abstracts teaches new employees the art of indexing by means of a sequential program, except that no machiue a t all is used. The consecutive items are typed on a deck of 3 X 5 cards. Experience with the program has been so favorable that plans are under way to teach at least five other subjects by the same method. The main advantage is that it is no longer necessary to spend a great deal of time with the learner. I t is evident that the physical mechanics of presentation of a Skinner program require as a minimum only that (1) each program item appear separately, in proper order, (2) a place be provided for the student to record each answer, and (3) the correct response be available for immediate check. This minimal presentation can be made with a set of numbered cards, or even with a file folder which has two small areas cut out so that a program sheet can be inserted in the folder, each item read and answered, and the sheet pullcd up to the next item. A simplified approach to an actual machine consists of a small box with a roller or platen enclosed a t each end, with the question and answer openings cut in the top of the box; the program would then fit on a paper belt, over the rollers, to be advanced from item to item by turning a knob. Thus the Skinner program is adaptable to many methods of presentation. Though an actual machine is doubtless preferable, and perhaps necessary for use by a student body, the less mechanized methods are equally effective for the learner who is seriously bent 592


Journal of Chemical Education

on learning a new field, especially if it is on-the-job training. The Multiple Choice Response

Though it is true that the multiple choice response is guilty of suggesting wrong answers, it is likely that in some situations the fault is more than offset by other advantages, particularly if the skill being taught is not purely verbal. The advantages offered are u7ort.h consideration; when the student selects the right answer, the machine-can not only tell him that he is right, but can recapitulate the correct train of reasoning, providing confirmation and repetition. For a wrong answer, the machine can tell why the answer is wrong, repeat the relevant ideas, and give the student another chance. A particularly attractive multiple choice teaching machine is the "scrambled book" (Figure 3) developed by Norman Crowder. After reading the first item, the student decides which of the multiple answers is correct; for each answer a page number is given. The appropriate page discusses the chosen answer, right or wrong, and then either poses a new problem incorporating the learned material, or refers the student back for another try if the answer was wrong. The items and answers are deliberately not in the same order as the numbered pages, so that it is not possible simply to skim through the book, but rather one follows a sequence of pages dictated by his understanding. The scrambled book is attractive since it is a device that can be constructed by any teacher with aid of a duplicating machine and stapler. It is easy to envision more complex machines that might be made if a school system decided to make an investment of a few thousand dollars. The program might, for example, be 35-mm slides stacked in a console which would project each slide onto a viewing screen as selected by a button or set of buttons. Such a machine could store a much larger program, running into tens of thousands of items. It is desirable to have the teaching machine completely self contained, but the scope of machine teach-

page 5 The molarity of a solution is defined as the number of gram formula weights of solute in one liter of solution. What weight of NaOH is required to make two liters of 0.3 M solution? 2 Page 17 a. 40 X b. 40 X 0 . 3 X 2 0.3 c . 40 X

Page 2 Page 34

page 17 2 a. Your answer was "40 X -" 0.3 Molarity is the number of gfw in a liter of solution. One gfw of NaOH is 40 g, so you would need 40 g of NaOH LO make one liter of 1 Maolution. Tomnke twolitersof 1 Msalution vou need rwice as much NaOH, 80 g. But you w&t twoliters of 0.3 M solution. This requires less than 80 g NaOH since 0.3 M is less concentrated than 1 M. But dividing 80 by 0.3 gives 266.6 g, which is more. Turn back to page 5 and try again. cage 34 Your answer was "40 X 0.3 X 2. You are correct. One gfw of NaOH is 40 g? so you would need 40 g of NaOH to make one bter of 1 M solution. To make two liters of 1 M solution you need twice as much NaOH, 80 g. Since 0.3 M is only 0.3 as concentrated as 1 M, you needed only 0.3 as much NaOH. You have now weighed out the right amount of NaOH. How much water are you going to use? a. Enough to dissolve the NaOH lus enough solution to make the volume of !etl exactly two liters. page 73 b. Two liters. page 27 c. 2000 g. page 8

Figure 3. Port d o multiple-choice teaching moshint program on con. centration$ of solutionr. Three points should b e noted: ( I ) the corred onrwer p a g e confirms t h e 3tudent'r choice (reward), repeats relevont reoroning, a n d arks a new question building on the o l d ; (2) wrong answer poges re-exploin concept a n d provide for retrial; and (31 relatively inform01 and personal text. (Text b y Moger.1

ing can be greatly broadened by use of collateral materials. For example, if part of the program is to teach use of refercnce materials or ability to interpret charts and tables of data, then the program questions may require use of the chart, table, or other material. The machine program might,also consist of questions or statements about a photograph, model, or diagram, as for example, electric circuits, working machines, theoretical models, and so on. The most desirable type of program for covering a particular field of knowledge will thus depend on the kind of skill or ability to be taught. Some Teaching Machine Experiments

Experiments with teaching machines are being carried out on a wide scale. Various branches of the armed services see in them a means for teaching many subjects faster and more thoroughly, industry looks for a means

to teach specialized information needed for various jobs with less expenditure of time, money, and teaching talent, and schools are experimenting to develop programs for courses. Development of teaching machine theory still lies in the hands of a few, notably Skinner and Holland of Harvard University and their colleagues. Mager, U. S. Army Air Defense Human Research unit, and Crowder of Western Design are prominent among the leaders in the development of machines and programs. The Department of Psychology a t the University of Georgia has taught a semester of psychology by machine. The only real difficulty they had with these students was that so many of them got a grade of 100 on the examinations that the school had been using over a period of years that they had to develop new and harder examinations. The poorest student got a mark of 84, and it was a rare student who scored this high in the conventional course. The armed services have found with teaching machines that new recruits could be taught trouble shooting on a particular complex radar outfit in less than half the twelve weeks required by lecture and field work, with more effective results. An experimental course in German offered a t Harvard trained students to a proficiency equivalent to that of the regular students who completed a regular full semester course. Average time of learning via the teaching machine was 47.5 hours, while students in the regular course spent 48 hours in class plus the time required to study and do the homework. The teacher's time was cut from 48 hours of teaching plus n hours of preparation and grading to virtually nothing. Harvard is presently in the second year of teaching a substantial part of their Natural Sciences 114 course by machine. This is described in reference (Z), but one noteworthy result is that in revising the program they are seeking to lessen the motivational effects of the machine program! Certainly this is the first time that sort of adjustment has been necessary with teaching materials. At Ohio University the author has presented a "scrambled book" program dealing with the kinetic theory of gases to two classes in general chemistry and one class in physical chemistry. Half of each class was given the book, without comment. After the usual mid-semester examination, in which those who received the book scored about 20 per cent higher (and with a fourth as many wrong ideas), the students were invited to comment anonymously. About half the students did write their reactions; most wanted more such material, particularly for the more troublesome material; a fair number felt that such easy material was an "insult to their intelligence," which is apparently a fairly common reaction since it has been reported in other teaching machine experiments. Notable among experiments in automated instruction a t several colleges are those a t Hamilton College and at Earlham College. The Earlham project is a threeyear experiment in programming in English, genetics, Russian, Spanish, and statistics, with further work in chemistry, music, and psychology. This program is supported by the Department of Health, Education and Welfare, and is under the direction of John Barlow. The Hamilton College program under John Blyth is Volume 36, Number 12, December 1959

/ 593

A solution consists of a dissolved substance, called the solute, and the substance in which the solute is dissolved is called the solvent. If suear is dissolved in water.. sunar - is called-the Syrup @ a solution of sugar in water. The solvent .Salt dissolves in water to form a Sodium hydroxide dissolved in alcohol forms a solution in which the alcohol is the Alcohol dissolves in water. If a small amount of alcohol is in a large amount of water, the dissolved solute is considered to be If a little water is dkolved in a large amount of alcohol, it is best to call water the-. Air dissolved in benzene forms a Silver and gold melted together form a solution. When cooled to a solid, the metals do not separate. The solid is still

Figure 4. Part of a Skinner-type program introducing the i d e m and vocobuiary of solutions. Note progression from simple definition to more complex ideas, and repetition of both words ond idear. [Text by Day.)

supported by the Fund for the Advancement of Education. It is in its second year and also covers several fields. A Number of Questions and Some Answers

Several questions suggest themselves immediately: (1) when we speak of "small steps" just how small do we mean, and is it not possible for them to be too small? (2) Can't the student cheat by peeking ahead, unless the machine is elaborately "student-proof," and would not cheating spoil things? (3) Some students can easily take larger steps than others; is there not a possible provision for such individual differences? If the steps are too small, might the work not be unduly tedious for the bright student? It is true that a fairly common reaction to a small-step program is that the student feels it is too easy. Though this is a minority reaction, H o m e and Glazer of the University of Pittsburgh have found that the smaller the steps in the program, the higher the scores made by the students when tested; even for those who complain about the too-easy steps. They find further that the class interest is directly proportional to the ratio of right to wrong answers. Theoretically the steps should be so small that the student never fails; in fact, no one has succeeded in writing such a program. That the student should succeed often and fail rarely seems certain, probably about 10 to 1, though the optimum ratio has not been determined. Occasional failure may provide challenge and spice, but as all teachers know from experience, frequent failure leads to discouragement and frustration, while many failures lead to complete loss of interest and a strong desire to avoid the failure situation. If a student feels he cannot avoid failure in a subject, he simply avoids the whole situation by not taking the subject, or by dropping out of school altogether. The range of student abilities can also be accommo594


Journal of Chemical Education

dated by providing alternate paths through the machine program. If all students cover identical material, then the statement that each student goes at his own pace merely means that they cover the same material in different times. For a machine teaching program to be entirely self-contained, the steps must be so small that the st,udent never errs, or the machine must provide correction for the mistakes made. There are two ways which have been developed to provide different paths for students of differing abilities; Wycoff a t the University of Wisconsin uses a Skinner-type program, in which the student is presented only with every fourth item. When the student makes an error, the machine presents the intervenmg thrpe steps which make the student able to succeed on the larger step. Thus the brightest student, capable of taking the biggest steps, covers the material in only one-fourth of the total program, while even the poor student could cover the material by covering every single step. The intermediate student takes the big steps where he can and is helped by the smaller steps when help is needed. Thus the total number of items and path followed would fit each student exactly. The multiple choice programs also can make further provision for individual differences in much the same fashion. When a student chooses a wrong answer, the machine cannot only re-explain, but direct him to an alternate sequence of simpler steps which will eventually return the student to the original problem, but more practiced in the steps needed for its correct solution. A point usually raised about machine programs is, "But won't the student cheat by looking ahead or peeking where he knows the answer to be hidden?" Experimenters have had two relevant experiences in common; first, that cheating is directly proportional to the difficulty of the material; that is, cheating is to be expected only when the student finds himself unable to produce the answer honestly; and second, that since the student learns the correct answer by cheating, then cheating can legitmately be considered one way of learning. And if the student learns the material correctly, who cares how? In experiments where cheating was noted and recorded, there was no significant differences in the final achievement between cheaters and non-cheaters. Use or Misuse?

It is possible to program an entire course in chemistry, but the immediate and most effective procedure will probably be the development of programs to cover some single coherent body of theory, such as the kiueticmolecular theory or the first law of thermodynamics. This should insure adequate learning of fundamental theory and a t the same time impress the student with the importance and coherence of the topic by its being singled out for special treatment. It is also feasible to use collateral or reference material with a machine program. For example, the Chemical Abstrmts indexing program requires reference to the index to one volume to obtain some answers. Programs must inevitably be written by the subject matter experts rather than the psychologist. The teacher who writes a program in his subject will early discover two things: the extraordinarily close analysis

of the logical structure of his material will invite re-examination of many of his own ideas; and no matter how carefully written the program may be, student responses will quickly reveal those items which are not crystal clear a ~ l dneed to be revised. Making a statement for uncritical student acceptance is easy; it is a different matter entirely to outline the path so clearly that every student can follow it with complete success. Any really successful program will probably have been revised at least two or three times in the light of student responses. Those teachers who experiment with programming are encouraged to follow through a t least two such revisions before attempting to assess the success of the experiment. A word of caution is in order a t this point. Not every mechanical gadget is a teaching machine, and many kinds of products will appear on the market shortly. Each should be investigated carefully. The most important item is the program itself, which should start from a well-defined point and proceed in logical, very small steps, each of which must call for a decision aud action on the part of the student. Study guides, flash cards, outlines, self-testing machines, and the like, whether accompanied by mechanization or not, are not teaching machines. They differ in the essential point that they cover old, or learned, material, and the questions presented may be at random in that they do not have to adhere to a logical step-by-step sequence of material. That "no educational experiment has ever been known to fail" is an old clich6. In a realistic assess-

ment of the potential of any of the teaching methods, whether by teaching machine, television, movies, or other, the novelty of the situation is itself a potent source of motivation, as is the student's knowledge that he is part of an experiment or something new-. The real question, which only time can reveal, is bow the students will react when the method is routine. We can expect that any method with a savor of novelty might show some improvement in student performance. It is the tremendous improvement, the truly astonishing results uniformly reported for teaching machines, that commands attention. And the principle seems sound enough: if the academic meat is cut small enough, the student can partake without mental indigestion, and indeed might even acquire a taste for the stuff! Bibliography The interested reader will discover substantial bibliographies in the review articles listed here. PORTER,DOUGLAS."A Critical Review of a. Portion of the Literature on Teaohing Devices," Harvard Educational Review, 27, 126147 (1957). B. F., "Teaching Machines," Science, 128, 969-77 SKINNER, (1958). FERSTER, C. B., AND SAPON,S. M., "An Application of Recent Developments in Physiology to the Teaching of German," Hamad Educational Review, 28,5%69 (1958). R., ''Readings in Automation LUMSDAINE, A. A., AND GLASER, of Teaching," American Institute for Research, Pittsburgh, Pennsylvanis. In press.

Volume 36, Number 12, December 1959