The Importance of Maintaining A Balance between Explicit and implicit Objectives
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Today, one finds a greater numher of general chemistry texts covering more material, in greater depth, than ever before. Although the select group of students placed in the core general chemistry sequence may he better prepared, they are often overwhelmed by the amount of material they must cover in the limited time available. This situation may be remedied by using behavioral ohjectives. This is most easily done by using a textbook with explicit ohjectives. Usually, these texts will have a preamble or epilogue pointing out some practical or particularly interesting aspects of the chapter, a list of ohjectives which the student is supposed t o achieve, the core material with numerous examples of calculations, a problem set, and mavbe even a self-test with answers. The nrohlem is that coukes using these texts have often turnei exclusively to exnlicit obiectives, nealectina implicit obiectives. ~ e f o r egoing any f;rther;let-me cla;ify what is meant by explicit and implicit objectives. Explicit ohjectives specify a terminal performance; they are concerned with a "product". Implicit ohjectives, on the other hand, are concerned with the develonment of "nmcesses". There is a negative and a positive Ade to both types of ohjectives. Consider some of the advantages . exnlicit obiectives have forstudents 1) All the guess work (trying to "psyche-out the Prof.") is taken out of studying, since the student knows exactly what is expected of him. As a result, his time is spent more effectively and efficiently. 2) Panic is eliminated on examinations. 3) Self-tests and problem sets become positive reinforcements since the students' answers usually agree with the given answers, thereby increasing the probability of the correct response occurring again. 4) Since the objectives are definitively stated and the material is clearly laid out in the text, faster students may work ahead when they have time. Because of the clear-cut way the material is organized, the teacher also has the advantage of being able to spend more time going over the more difficult concepts, answering students' questions, and pointing out interesting highlights. The problem with explicit ohjectives is that the student doesn't have to figure out anything for himself. He does his homework by following the sample problems in the text, using the ready-made equations. Exams never have any surprise questions or questions that go one step beyond what was covered in the text. This has several adverse effects 1) Good students are not challenged and may easily become bored. 2) The lecture portion of the course may become a breeding gmund for answer-orientedstudents. 3) The average student may be overwhelmed by the number of explicit objectives since, unfortunately, the virtue of specificity involves the burden of multiplicity. Presented at the 28th Annual Northwest Regional ACS Meeting, Washington State University, June 1973. 328 / Journal of Chemical Educatbn
provocative opinion is an overernphaG on conformiry (1,. causing many students tofail roenerriseany rurimiry orrreativit,
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In short, the exclusive use of explicit objectives does not encourage students to think. Well, what about implicit ohjectives? Implicit objectives leave room for the student to actively participate in learning. There is a great deal of evidence from psychological studies which indicates that learning is not a passive matter and that education does not occur by osmosis (2). The use of implicit ohjectives gives a student a chance to tackle a challenging problem and using his factual knowledge, intuition, and creativity, allows him to propose a plan of attack that might lead to a solution of the problem. There is an ancient Chinese proverb: "I hear.. .and I forget. I see. . .and I remember. I do.. .and I understand." Implicit ohjectives give a student a chance to do something for himself. One implicit objective many teachers have in common is to have their students know what science is and how scientists work. After all, we know science is not just a body of knowledge hut a process of inquiry. It is up to us to convey this to our students by striving to teach the process of inquiry, the means to an end and not only the end results. There is a line from Bacon's essay On Studies (3) which says, Read not to contradict nor to believe, hut to weigh and consider. Some books are to be tasted, others to be swallowed, and some few to be chewed and digested. Unfortunately, sometimes we keep a student so busy chewing, he has little chance to cultivate a sense of inquiry. Implicit ohjectives can give him that chance. This is not to say that implicit ohjectives have no drawbacks, because they do. 1) Since they cannot be specified exactly, they cannot be easily tested. 2) It takes more time for a student to figure something out for himself than it does for you to tell him the answer.
The exclusive use of either explicit or implicit ohjectives will tend to enhance the disadvantages of those ohjectives. There is a humorous story (4) that shows what can happen when there is an imbalance between the two types of objectives. This story is about a young investigator who conditioned a flea to respond to the command " J u m ~ " .At everv sten of the exneriment he made careful and detailed notes in his lab hook; Procedure: The two bind leas of the flea were arasned securely between thumb and fGefinger of the righi hand. The flea was held gently in the left hand with the thumb of that hand underneath the abdomen. Both legs were removed simultaneously by means of a sharp pull. The flea was placed on the conditioning table in position 3-y, facing north. The experimenter then said, "Jump",' in a normal tone. Observation: The flea jumped.
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Procedure: Next the experimenter removed the flea's legs in three stages. After the first two pairs of legs were removed i t still jumped vigorously when the command jump was given. After the last two legs were removed, however. the flea iust remained auiverinz on the table even when the command, "Jump", Gas repeated. Observation: When a flea has six legs . removed, i t becomes deaf. Well, I think yon can see the problem. The question is how can one achieve a balance between explicit and implicit objectives in order to avoid a situation such as the one I described, so as to maximize the advantages and minimize the disadvantages of each. We in science are very fortunate to have both lecture and laboratory time. So, the lecture portion of the course can be built around explicit objectives, while the laboratory can focus'on implicit objectives. Of course a certain amount of laboratory time must be spent learning various techniques or skills. The instructor's identification of the explicit ohjectives involved in mastering a skill can greatly facilitate a student's progress (5). This, in turn, leaves the student free to explore-the more engaging, fundamental aspects of an experiment inherent in implicit ohjectives. According to Gagne, an educational psychologist, it is desirable first to acquire structurally organized knowledge and then to concentrate on problem solving and discovery (6). The trouble with many general chemistry courses is that lectures and labs are not well correlated. As a result, the students lack the body of knowledge needed to tackle a laboratory problem in the most meaningful manner possihle. Hence experiments are often carried out via the cookbook method with most of a student's effort devoted to obtaining the "right answer", the one expected in the lab manual. Is that what we want students to get out of lab, "the right answer", or do we really want them to fulfill implicit objectives such as: to consider how experimental
information was, or might he obtained, the kinds of assumptions, observations, and reasoning that might have led to such information, and to recognize and evaluate sources of errors? One might also ask what could he done with certain information once it was obtained, and whether it could he used directly or indirectly in some other area. In summarv then. I see science as both a hodv of knowledge and a process of inquiry or ways of dealing with this knowledee. The best wav to master the bodv of knowledge seems t'be by using explicit objectives in the lecture poitiou of the course. The best way to learn the process of inauirv and method of dealine with information seems to be dy ;sing implicit objectives in the laboratory portion of the course. In this wav the balance between e x ~ l i c i tand implicit ohjectives can be maintained benefiting both teacher and student. Literature Cited (I) Ebsi, R.L., "The Impact and Impmvcment of Scbwi Testmg Prowma", Psut 2 of Yearbook of Naf'l. See. for the Study of Education, Chicago Univesity PIOM, Chicago, 1962, p. 28. (2) saoford,F ~ U ~ "O P~ ~. ~ c ~Aoscientific ~ o ~ : study o ~ M ~ wadsaonh ~ " . P U ~ CO.. I. San Franeiro, 1961. (3) Bacon, Frmeb, "French Bacon" (Editor: Johnston, A,). Batsford. Endsnd. 1965, p. 73
R., "Payehoiobical Theories and Human Leaminr: Kongor'a Repat", BmoLs/Cole, Csliiornis. 1972. p. 11.
(4) Idranmis, Guy
(5) Young, J . A,, and Hill. B. W., in "Pmeeedings of the Sympasium on Self Paad In-
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atrudion in Chcmiatrv" (Editor: Shahhashiti.. 8.2.1. . .. Chemical Education Publ. Co.. Pennsylvania, 1973, p. 69. (6) Gscne, Roben, "The Conditions of Learning". 1st Ed., Holt. Rimhan, and W h aton, NeuYork, 1965.
Joan T. Lebsack Washington State University Pullman, 99163
Volume 52, Number 5. May 1975
329
