University of Southern California Dissertations and Theses

Advance Organizers And The Enchancement Of Meaningful Verbal Learning Andretention

(USC Thesis Other)

Advance Organizers And The Enchancement Of Meaningful Verbal Learning Andretention

PDF

Download

Open document

Flip pages

Download a page range

Download transcript

Copy asset link

Request this asset

Transcript (if available)

Content ADVANCE ORGANIZERS AND THE ENHANCEMENT OF MEANINGFUL VERBAL LEARNING AND RETENTION by Paul Rochester Munford A Dissertation Presented to the FACULTY OF THE GRADUATE SCHOOL UNIVERSITY OF SOUTHERN CALIFORNIA In Partial Fulfillment of the Requirements for the Degree DOCTOR OF PHILOSOPHY (Education) January 1972 72-11, 9*15 I I HUNFORD, Paul Rochester, 1935- ADVANCE ORGANIZERS AND THE ENHANCEMENT OF MEANINGFUL VERBAL LEARNING AND RETENTION. University of Southern California, Ph.D., 1971 Education, psychology University Microfilms, A X E R O X Company, Ann Arbor, Michigan THIS DISSERTATION HAS BEEN MICROFILMED EXACTLY AS RECEIVED UNIVERSITY OF SOUTHERN CALIFORNIA THE GRADUATE SCHOOL UNIVERSITY PARK LOS ANGELES. CALIFORNIA S 0 0 0 7 This dissertation, •written by .........Paul Rochester Munford.... under the direction of h..i&* Dissertation Com mittee, and approved by ail its members, has been presented to and accepted by The Gradu ate School, in partial fulfillment of require ments of the degree of D O C T O R O F P H I L O S O P H Y C J L u L j j f . *7* ° D m * Date-October ~2J&* . . . 1 9 . 7 . 1 PLEASE NOTE: Some pages have indistinct print. Filmed as received. UNIVERSITY MICROFILMS. ACKNOWLEDGEMENTS I wish to express thanks to my Dissertation Committee, and especially to Doctor C. Edward Meyers, Chairman, for his valuable suggestions and comments. ii DEDICATION This work is dedicated to my father, the late Percy Tar1ton Munford, and to my mother, Ruth Esther Munford. iii TABLE OF CONTENTS Page ACKNOWLEDGEMENTS ........................ii DEDICATION..............................................iii LIST OF T A B L E S ................................................................................................................ V LIST OF FIGURES........................................vi Chapter I. INTRODUCTION................................. 1 II. REVIEW OF THE RESEARCH.........................17 III. METHODOLOGY.....................................32 IV. RESULTS......................................... 45 V. SUMMARY, DISCUSSION AND CONCLUSIONS . . . 53 REFERENCES...............................................59 A P P E N D I X ...............................................64 iv LIST OF TABLES Table Page I. Sample Size, Means, and Standard Deviations for All Three Treatment Groups for Initial Learning.......................................46 II. Analysis of covariance for Scholastic Aptitude Test— Verbal Scores for Initial Learning.......................................47 III. Analysis of Covariance for Scholastic Aptitude Test— Quantitative Scores for Initial Learning .......................... 47 IV. Analysis of Covariance for Scholastic Aptitude Test— Total Scores for Initial Learning.......................................48 V. Sample Size, Means, and Standard Deviations for All Three Groups for Retention . . . 49 VI. Analysis of Covariance for Scholastic Aptitude Test— Verbal Scores for Retention .................... . . 5 0 VII. Analysis of Covariance for Scholastic Aptitude Test— Quantitative Scores for R e t e ntion....................................51 VIII. Analysis of Covariance for Scholastic Aptitude Test— Total Scores For Re t e ntion....................................52 v LIST OF FIGURES Figure Page 1. The Assimilation Process........................7 2. The Experimental Procedure ................ 39 vi CHAPTER I INTRODUCTION Ausubel (1968) made an important distinction between the psychologist's interest in general laws of learning on the one hand and the educational psychologist's interest in school learning on the other. The psychologist is concerned with . . . the nature of simple, fragmentary, or short term learning experiences which are presumably more representative of learning, rather than the kinds of long-term learning involved in assimilating extensive and organized bodies of knowledge. (Ausubel, 196 8:8) Ausubel (1968) saw the following kinds of problems, particularly suited for psychoeducational research: (a) discovery of the nature of those aspects of the learning process affecting the acquisition and long term retention of organized bodies of knowledge in the learning; (b) long-range improvement of learning and problem solving capacities; (c) discovery of which cognitive and personality characteristics of the learner, and of which inter personal and social aspects of the learning environ ment, affect subject-matter learning outcomes, motivation for learning, and typical ways of assimi lating material: and 1 2 (d) discovery of appropriate and maximally efficient ways of organizing and presenting learning materials and of deliberately motivating and directing learning toward specific goals. (1968t8) However, in the relative absence of theory and research for the bulk of the learning which occurs in the classroom, namely, learning of meaningful verbal material, educational psychologists have attempted to translate to the classroom the research findings based on methodologies of a nonmeaningful nature. As a result, meaningful subject matter is still largely presented to students in a pri marily rote fashion and the understanding of the process by which meaningful material is learned has been fore stalled. Hence, elucidation of the process of meaningful learning may be attained by considering the nature of the material to be learned} that is, by means of theory construction and experimentation in the domain of meaning ful verbal learning. One such theory is proposed by David P. Ausubel in Educational psychology; a cognitive view (1968). Before an exposition of the theory itself, key terms will be defined to facilitate understanding. Cognitive Structure Cognitive Structure refers to the stability, clarity and organization of the learner's knowledge in a 3 given area of study. Even though this knowledge is itself a result of a learning activity and thus a dependent variable, it is also, once acquired, the most significant independent variable influencing the learner's ability for obtaining more new knowledge in the same subject matter area. Obviously, the existence of specifically relevant anchoring ideas at an appropriate level of inclusiveness is crucial for assimilating new meaningful material. Cognitive Content Cognitive Content pertains to the actual ideas and information embodied in the learner's subject matter knowledge within a given discipline or in a lesson to be mastered. Cognitive Style Cognitive Style means the learner's self-consist ent and idiosyncratic trends in cognitive organization and functioning and to inter-individual differences in them. Some aspects of cognitive style have been identi fied as: intolerance for ambiguity or tendency for premature closure; intolerance for unrealistic experience; leveling-sharpening; need for simplification; degree of cognitive differentiation; explication and importing of 4 detail in memory; long-term versus short-term memory? constriction or flexibility in problem solving; and preference for broad or narrow categorization. According to Paul (1959), cognitive style mediates between motiva tion and emotion, on the one hand, and cognition, on the other. Meaningful Learning The process whereby symbolically expressed ideas are nonarbitrarily related to what the learner already knows, specifically to some existing relevant aspect of his structure of knowledge, constitutes meaningful learn ing. It presupposes that the learner manifests a set to incorporate the potentially meaningful material in a non verbatim fashion and that the material itself be poten tially relatable to his cognitive structure. It is this basic difference in kind of relatability to cognitive structure (arbitrary and verbatim versus nonarbitrary and substantive) that accounts for the basic difference between rote and meaningful learning processes. Meaning The end product of a meaningful learning process is the acquisition of meaning. This refers to the 5 differentiated cognitive content evoked in the learner by a symbol, or group of symbols, previously incapable of producing this reaction. That which was external becomes converted into an individualized psychological state for content of consciousness. From this point of view, meaning is seen always to imply some form of representa tional equivalents between symbols and cognitive structure. Ausubel's theory of meaningful reception learning and retention will now be presented. The Theory of Meaningful Reception Learning and Retention The principle of assimilation is the essential one for explaining the process of learning or acquiring new meanings. The assimilation process occurs as follows: When a new, potentially meaningful idea is related to an established idea in cognitive structure, the interactional product that results is the emergence of the new meaning. This is the type of meaning that results when a potentially meaningful concept or proposition can be subsumed under a more inclusive established idea in cognitive structure as an example, extension, elaboration, modification or qualification of the established idea 6 . . . the meaning A1a' that emerges when a is related to and interacts with A in this fashion, is the product of this interaction between them, and is itself a differentiated cognitive content. (Ausubel, 1968:90) This is diagrammatically represented in Figure 1. The assimilation process implies a progressive differentiation of cognitive structure from regions of greater to lesser inclusiveness. Each region of differen tiation is contiguously ordered in a hierarchical arrange ment with the apex of the hierarchy consisting of the most inclusive, stable, general and abstract ideas. As new material is cognized, it interacts with and is appro priately subsumed under a relevant and stable subsumer already existent in the learner's cognitive structure. Hence, the subBumer provides "ideational scaffolding" for the acquisition of new information. Initially, the consequences of the assimilation of new material into an already organized cognitive struc ture facilitates both initial learning and retention. Only the orienting, the relational and cataloging opera tions are involved. In addition, anchorage for the new material is provided which enhances its retention for future reproducibility. The information remains disso ciated from its subsuming concepts and is reproducible as A + a ^ A' a* A - Established idea in cognitive structure a = New, potentially meaningful idea A'a1 = New meaning Figure 1.— The Assimilation Process 8 individually identified entities for a variable period of time. However, the new subconcepts are susceptible to the erosive influences of the tendency toward conceptualiza tion. Larger, more inclusive concepts are more economical to retain than are the subconcepts and the specific infor mation. Ausubel calls this process the obliterative stage of assimilation. The specific ideas become progressively less dissociable as entities and finally are no longer reproducible. They are forgotten. It follows from the . . . assimilation process, that existing cognitive structure itself--both the substantive content of an individual's structure of knowledge and its major organization properties in a particular subject matter field at any given time is the principal factor influencing meaningful learning and retention in the same field. (Ausubel, 1968:127) Thus, it is largely by strengthening relevant aspects of cognitive structure that new learning and retention can be facilitated (Ausubel, 1969:128). "When we deliberately attempt to influence cognitive structure so as to maximize meaningful learning and retention, we come to the heart of the educative process" (Ausubel, 1968:128). One of the most important factors affecting the learning and retention of new meaningful material is the availability in cognitive structure of specifically 9 relevant anchoring ideas that are inclusive enough to provide optimal relatability and anchorage. If these specific relevant ideas are not available in cognitive structure for the learner attempting to acquire meanings, he will most likely attempt to utilize ideas that are only tangentially or vaguely relevant. Another possibil ity is that he may employ a rote learning process. In either case, the net result is inefficient anchorage of the new material to existing cognitive structure, which results in the acquisition of unstable and ambiguous meanings. Therefore, in order to avoid these pitfalls, it is preferable to introduce suitable advance organizers whose relevance to the learning task is made explicit and which function as facilitators of assimilation rather than to rely on the haphazard availability or use of inappropriate anchoring ideas in cognitive structure. Logical and Psychological Meaning The distinction between psychological and logical meaning hinges on the relationship between the learning material and the learner. When considering only the material, we are dealing with logical meaning. When we are concerned with the assimilation of this material by 10 means of idiosyncratic, nonarbitrary processes, we are talking about psychological meaning. Logical meaning, therefore, refers to the inherent meaning in certain kinds of symbolic material by virtue of its very nature. Such material manifests logical meaning if it can be related on a nonarbitrary and substantive basis to correspondingly relevant ideas that lie within the realm of human learning capability. (Ausubel, 1968) This of course does not mean that all propositions with logical meaning are empirically valid or even logically defensible. Psychological meaning occurs when logical meaning is transformed into idiosyncratic cognitive experience by means of nonarbitrary and substantive relatability to what already exists in the learner's cognitive structure. The psychological meaning is dependent not only on the material's logical meaning, but also on the learner's possession of relevant ideas already existing in cognitive structure. Even though psychological meaning is an idiosyncratic affair, this does not mean that shared understandings cannot occur. The individual meanings of propositions which members of a group possess are usually ordinarily sufficiently similar to allow interpersonal 11 communication and understanding. Thus, we can see that the nature of the learning material alone is not the sole determiner for actualizing psychological meaning from potentially meaningful material. One also has to be concerned with the existing cognitive structure the individual brings to the new learning situation. One outcome of this conceptualization has resulted in the development of advance organizers. The Use of Advance Organizers Advance organizers, as they are experimentally introduced in advance of the learning material itself, are typically short expository passages. The organizers are presented at a higher level of abstraction, generality and inclusiveness than the material to be learned. Substan tively, they are constructed in accord with their appropriateness for explaining, integrating, and inter relating the materials they precede. In contrast to organizers, summaries and overviews cure usually at the same level of abstraction, generality and inclusiveness of the material from whence they are derived. Ordinarily, they simply emphasize the material's salient points by omitting less important information and relying on 12 repetition. The rationale for the use of organizers is explicitly based on the following: a. The learner needs relevant and otherwise appro priate established ideas already present in cognitive structure to make new ideas potentially meaningful and to give them stable anchorage. b. There are advantages to be derived from using the more general and inclusive ideas in a given area of subject matter to function as anchoring ideas for subsumers. c. Existing relevant ideas in cognitive structure are both identified by the organizer, as well as the relevant relational attributes between the organizer and the learning material itself. In sum, the organizer serves as a bridge between what is already known and what the learner needs to know in order to learn the task at hand. Hence, the organizer's purpose is to provide • . . ideational scaffolding for the stable incor poration and retention of the more detailed and differentiated material that follows in the learn ing passage • . . (Ausubel, 1968:148) 13 In the case of completely unfamiliar material, an 'expository' organizer is used to provide relevant proximate subsumers. These subsumers, which bear a superordinate relationship to the new learning material, primarily furnish ideational anchorage in terms that are already familiar to the learner. (Ausubel, 1968:148-149) From the above theoretical background and considerations we come to the essential and specific concerns of the present study. The Present Problem In attempts to empirically ascertain the verity of the foregoing theoretical rationales and implications, Ausubel and others have conducted two major research studies. These works have centered about the efficacy of the use of advanced organizers for facilitating the learning and retention of meaningful verbal material. In both cases the outcomes have tended to support the foregoing contentions, however, not without equivocation. Specific shortcomings of these studies will be elaborated upon in the following chapter; however, they all suffer from lack of adequate control for transfer effects. In addition, the data collecting procedures obscured the separate effects of initial learning from differences in 14 retention, as a consequence of the use of the organizer. Finally, statistical significance in favor of the organizers' efficiency in heightening learning and reten tion was not unquestionably demonstrated. This study, therefore, will attempt to correct the above-mentioned limitations which may be partially responsible for the minimal response by the academic com munity to a well constructed theory. Furthermore, Ausubel's research is seldom cited by others actively engaged in educational research, very likely because his views are at odds with the prevailing climate of opinion. The lack of attention to this research is a shame, because it seems possible that Ausubel's experiments are showing a kind of nonspecific transfer never before revealed with complex verbal task. (Anderson, 1967:158) Scope and Limitations of the Study The present study confined itself to written verbal material whose nature is basically scientific. The passage to be learned is of a moderate level of reading difficulty, appropriate for undergraduate, upper division college students who served as the subjects. The type of organizer used is of the expository style. That is, it has been so constructed as to provide the learner with "ideational scaffolding" for the more detailed and complex information which follows. The organizer's general, 15 Inclusive, stable and abstract concepts are the major subsumers for the new information to be cognized. This expository organizer is not to be confused with a compar ative organizer, the purpose of which is to compare and contrast the new information with that already existing in cognitive structure. For the purpose of this study, learning was defined as the number of correct responses on a multiple choice test consisting of forty-two items administered immediately after the learning trial. Similarly, reten tion was defined as the number of correct responses on the same test, administered one week, following the learning trial. The following hypotheses were proposed: Research hypothesis 1.— The initial learning of unfamiliar material preceded by an advance organizer is superior to the condition in which the material is pre ceded by an irrelevant historical passage or if followed by an advance organizer. Research hypothesis 2.— The retention of the newly assimilated material when it is preceded by an advance organizer is greater theui when the material is 16 preceded by a historical passage or followed by an advance organizer. These hypotheses are restated in operational form after a discussion of the procedure in the next chapter. CHAPTER II REVIEW OF THE RESEARCH Two studies involving the use of advance organizers have been undertaken by Ausubel and his asso ciates. They will be discussed in detail. Also, this chapter will review research concerned with other organizer-like facilitators of learning and retention. Two Studies The first experiment with advance organizers as they affect learning and retention was . . . to test the hypothesis that the learning and retention of unfamiliar but meaningful verbal material can be facilitated by the advance intro duction of relevant subsuming concepts (organizers). (Ausubel, 1960:267) Towards this end, 120 senior undergraduate students in an educational psychology course were selected as the experi mental population. The unfamiliar but meaningful learning material consisted of a specially prepared 2,500-word passage dealing with the metallurgical properties of plain 17 18 carbon steel. This material was considered to be unfamiliar, but the assumption was first tested by giving the retention test on the steel passage to a group of subjects who had not studied the learning material. From this experience it was learned that the material was of questionable familiarity to the subjects. Variables such as sex and major area of study were also found to be systematically related to the learner's degree of famil iarity with the verbal material. More will be said about this later in the chapter. Knowledge of the steel passage was given by a forty-two-item multiple choice test with a corrected split half reliability of .79. Scores on the test were normally distributed over a satisfactory range. The experimental procedures consisted of matching the control and experimental subjects on the basis of sex, major field, and ability to learn scientific material. This last criterion was determined by a subject's score on a test covering a passage on the endocrinology of human pubescence, which all subjects had to study. Subjects were then placed into an experimental or control group. The experimental group twice received the advance 19 organizer which they studied five minutes, once forty- eight hours before exposure to the main learning passage and once immediately prior to receiving it. The control group was similarly shown an historical background intro duction before studying the steel passage. Both groups studied the steel passage for thirty-five minutes and took the multiple choice steel test three days later. Since the subjects were matched on the variables of sex, major field, and pubescent test scores, it was necessary to match experimental and control subjects across sections in order to obtain an acceptable number, which turned out to be 40. This was justifiable in view of the inter sectional homogeneity of variance. The distribution of the steel test scores for both the experimental and control groups did not deviate significantly from the normal. The mean steel test score of the experimental group was 16.7, as compared to 14.1 for the control group and a mean chance score of 7.2 (one-fifth of thirty- six) . Standard deviations of the two groups were 5.8 and 5.4 respectively. The difference between the means of the experimental and control groups was almost significant at the .01 level for a one tailed test. (Ausubel, 1960:269) The author concluded, "The experimental and con trol groups unequivocally supported the hypothesis" (Ausubel, 1960). 20 However, a careful critique of the experiment raises four questions. First: Was there adequate control over the possible direct contribution of the organizer by itself to the criterion measure? To this point, Ausubel states: The experimental introductory passage contained background material for the learning passage which was presented at a much higher level of abstraction, generality, and inclusiveness them the latter passage itself. It was designed to serve as an organizing or anchoring focus for the steel material and to relate it to existing cognitive structure. Princi pal interest was placed, therefore, on the major similarities and differences between metals and alloys, their respective advantages and limitations and the reasons for making and using alloys. Although this passage provided subjects in the experimental group with relevant background concepts of a general nature, it was carefully designed not to contain specific information that would confer a direct advantage in answering any of the questions on the steel test. The latter criterion was tested empirically and shown to be warranted when a com parable group of subjects made only a slightly better than chance mean score on the steel test after studying the introductory passage alone. (1960:268) This statement, therefore, leaves the question unanswered as to the degree of direct transfer conferred by the organizer alone, and hence, any obtained difference between the experimental and control groups could be explained as a consequence of proactive facilitation, rather than in terms of the organizer's functioning 21 indirectly via its properties of organization and "ideational anchorage." The second question is: To what extent was the criterion of unfamiliarity satisfied for the learning passage? Empirical proof of unfamiliarity was sought, therefore, by administering the retention test on the steel passage to a comparable group of naive subjects who had not studied the material; but although this latter group of subjects made scores which on the average were only slightly and not significantly better them chance, it was evident from latter analysis of the experimental data that scores earned by subjects who had studied the pass age were related to both sex and field of speciali zation. Male students and majors in science and art were better able to learn and retain the steel material than were female students and majors in English, foreign languages, music, and social sciences. Hence, the criterion of unfamiliarity was not completely satisfied, inasmuch as these differences undoubtedly reflected, in part, variability in relevant incidental experience influencing the leamability of the material. (Ausubel, 1960:268} In regard to this point, Ausubel continues: Because of some prior general familiarity with the contents of the steel passage, many subjects already possessed relevant and stable subsuming concepts. These obviously rendered less signifi cant potential learning advantages conferable by advance organizers. (1960:269) Another plausible outcome of prior familiarity could be generally to obfuscate the explanation of any differences obtained between the means of the experimental 22 and the control groups. The third question concerns the possibility that the experimental group may, in effect, have received an additional learning trial. Ausubel says: It could be argued, of course, that exposure to the experimental introduction constituted in effect a partial substantive equivalent of an addi tional learning trial. Actually, however, any substantive repetition was at most very indirect, since the introductory passage consisted of much more inclusive and general background material than was contained in the learning task itself and also provided no direct advantage in answering the test items. (1960:268-269) Nevertheless, as stated above, a strong possibility does exist that the organizer may have conferred a direct advantage in answering the steel test questions and there fore provided the experimental group with an additional learning trial. If this is the case, then the total time hypothesis would seem to apply. Bugelski states, It is the present hypothesis that in at least some areas of memorization, and under some conditions of presentation, the degree of learning will be a function of the total time, regardless of the dura tion of the individual trials or inter-item times. (1962:409) Thus, on the basis of this statement, one could conclude that any differences found in favor of the experimental group could be attributed to greater total time, rather than to the organizational properties of the experimental 23 introduction. Finally, the study under examination, although entitled "The Use of Advance Organizers in the Learning and Retention of Meaningful Verbal Learning" in actuality measured only differences in levels of retention. The testing of the learning passage took place for the first time three days after its original presentation. Hence, it would appear that the experiment is limited to studying retention with the effects of learning being implicitly observed. The second study involved the use of organizers to facilitate the learning of Buddhist doctrines (Ausubel and Fitzgerald, 1961). The following hypotheses were proposed: (1) . . . that to the extent that the organizer is rendered discriminable front related concepts (Christianity) established in cognitive struc ture, and hence to the extent that it increases the discriminability of the Buddhist learning passage from these Christianity concepts, it facilitates the learning and retention of the new Buddhist ideas. (196It266-267) (2) . . . it is hypothesized, for analogous reasons, that the discriminability (and hence the learn ing and retention) of the Buddhism passage varies as a function of the clarity and stabil ity of the learner's existing knowledge of Christianity and that subjects with relatively unclear and unstable concepts of Christianity 24 derive relatively more benefit from the organizers than do subjects with clear and stable concepts in this area of knowledge. (1961s267) The main learning task for all groups consisted of studying a 2,500-word passage on Buddhist doctrines. One experimental group was given a 500-word comparative organizer which explicitly compared the major ideas of Buddhism and Christianity, two days before studying the learning passage. Another experimental group studied as a parallel advance passage, an expository organizer which was devoid of references to Christianity. A control group studied in advance a historical introduction which dealt with the history rather than the ideas of Buddhism. Retention of the Buddhism material was tested three days and ten days after the learning session by means of equiv alent forms of a multiple choice test. On a three-day basis the comparative organizer was significantly effec tive in facilitating the retention of the Buddhism material. However, on a ten-day basis neither the compar ative nor expository organizer was significantly effective. The subjects had been divided into above and below median subgroups in terms of their scores on an objective test of Christianity. Subjects with the greater knowledge made significantly higher scores on the Buddhism retention 25 test than did subjects with less knowledge of Christianity. This positive relationship between knowledge of Christian ity and Buddhism was confirmed even when the differences in verbal ability were eliminated. The data supported the hypothesis that the learning and retention of unfamiliar verbal material varies positively with its discriminabil ity from related previously learned concepts established in cognitive structure and that this endogenously deter mined discriminability is a function of the clarity and stability of the later concepts. Hence, Ausubel con cludes , In the learning and retention of unfamiliar ideas and material that is relatable to established con cepts in the learner's cognitive structure, both comparative and expository organizers appear to be effective only in those instances where existing discriminability between the two sets of ideas is inadequate as a consequence of the instability or ambiguity of established concepts. (1961:271) This experiment, like the previous one, failed to control the organizer's direct contribution to the cri terion measure. In the author's own words: The special control group which only studied the comparative organizer (without any exposure to the Buddhism passage itself) made a mean score of 13.20 on the three-day Buddhism test and a mean score of 13.45 on the ten-day test. These scores were significantly higher than the scores of a comparable naive group which took the Buddhism test without being exposed to either organizer or learning passage, but were substantially below 26 those of the historical and two organizer groups. (Ausubel, 1961:271) The remaining portion of this chapter will review the research concerned with the influence of existing knowledge as it affects new learning in the same or related subject matter area. The review, which is only a sample of the work in this area, limits itself to those studies involving the transfer paradigm in which cognitive structure variables were manipulated in order to assess their effects on the acquisition and retention of new learning. The works cited are centered about meaningful material only to the extent that they use unconnected words, trigrams, sentence strings and the like because more relevant studies are unavailable. This paucity of research with meaningful subject matter thus highlights the significance of Ausubel's endeavors to subject meaningful verbal learning to the scientific method. The Effects of Preliminary Organization on Learning and Retention By means of prior training in organizational principles, Postman was able to demonstrate the enhancing effects of this activity in the learning and retention of rote material. 27 This series of experiments has demonstrated that learned rules of organization can systemat ically influence both the amount and quality of retention. Memory materials governed by a con sistent set of principles was used. By manipu lating the conditions of preliminary training, it was possible to influence not only the number of individual items retained, but also the quality of the errors in the subjects' reproductions. The more explicit subjects' preliminary training in the principles governing the stimulus material, the more their reproductions conformed to these principles. The effectiveness of such preliminary training increases with the retention interval. As the interval is lengthened, conformity to the principles increases progressively; there is a growing tendency to omit or rectify errors which violate the general principles. Finally, the more explicit the training, the less susceptible the memory material is to retroactive inhibition. (1954:63) Similar outcomes were obtained by Reynolds, who had one group learn simple sentences giving factual information about a map which they had previously studied, and other groups learn the same sentences with exposure to only portions of the map. The first group demonstrated superior learning of the sentences. The results were interpreted as indicating (a) that the integration of the verbal and percep tual stimuli into a total structure, rather than these components separately, was responsible for the transfer observed; and (b) that cognitive organization may facilitate simple verbal learning as well as complex and conceptual learning. (1966:382) 28 Neuton and Hickey showed that organizing introduc tory passages proved effective in learning concepts regarding the gross national product. They concluded, "Performance was faster when principles were stated first and when subconcepts were learned together rather than separately" (1965:145). The concept that all physical phenomena are based on energy transformations and that matter and energy are indestruetable was suggested by Watkins (1932) and later developed by Meredith (1961) in curriculum development. Schultz studied the effect of this principle on learning when used as a cognitive organizer in a science unit developed for sixth grade children. While the evidence was inconclusive regarding the general role of the advance organizers, it appears that advance organizers do facilitate learning when pupils lack the processing skill (analytic ability) necessary to reorganize information in dependently into suitably clear, inclusive, and stable cognitive structure. (1966:71) The Effect of Other Types of Prior Organization on Subsequent Learning and Memory The acquisition of new material can be facilitated by the learner's reliance on subsuming concepts already present in cognitive structure. This was demonstrated by 29 a series of experiments dealing with the learning of unfamiliar word meanings via relating them to the context in which they were used (Browner, 1957; Marx and Miller, 1964; Schwartz and Lippman, 1962). Another example of spontaneous antecedent organization is Osgood's (1953) study demonstrating the facilitating effect of grammar on word-sequence learning. Even with rote material, learning can be accelerated when meaningful organizational strate gies are employed. Matthews, who demonstrated that memory functions directly with the number of categories available for classifying items, concluded, Categories are important in the processing of information because they establish equivalencies in our heraclidian world, making it possible for the organism to profit by experience and react at a better than chance level with the environment. (1954:245) E. C. Poulton (1957) found that subjects' convictions about the veracity of statements correlated with their ability to recall them. By providing sets and means of training in "learning to learn" new concept acquisition can be enhanced. Reed (1953) demonstrated this with rats in a discrimination learning paradigm. Similar interpretations could be made from data obtained by Bruner (1957), Pubols 30 (1957) , and Sassenrath (1959). Kindergarteners trained in learning textural responses were found to benefit most when they experienced previous encounters of the same stimuli (Statts and Schutz, 1962). Antecedent context facilitates the reception of verbal material when it is tachistoscopically exposed at subthreshold levels (Hasselrud, 1959). Kendler and Karasik (195 8) found that concept formation is directly related to the availability of verbal responses. "Learning to learn" studies illus trative of the facilitating effect of the prior acquisi tion of general principles on later learning include those by Hendrickson and Schroeder (1941), Judd (1902), Overing and Traverse (1966). Also see Duncan (1956), Morrisett and Hovland (1959) , Katona (1940) , French (1954) , and Hilgard (1953, 1954). Conclusions The two studies by Ausubel and his associates, reviewed herein, indicated that the use of organizers tends to facilitate the learning and retention of meaning ful verbal material. However, it was pointed out that limitations in the experimental designs have led to inconclusive results. Namely, none of the studies has 31 included controls to demonstrate that the organizer alone does not enhance performance. Even though the organizers are reported to contain nothing that could directly con tribute to posttest scores, the possibility remains that they may have a direct transfer effect rather than an indirect one of influencing cognitive structure variables. For this reason, the present review has delineated in detail shortcomings in Ausubel's past experimentation, the correction of which, by the present replication, could produce different outcomes. Studies that were concerned with the effects of other organizer-type properties were reviewed, partly to illustrate that they are the only approximations to the actual study of meaningful material, except for Ausubel's work. Only those investigations were included that involved the manipulation of cognitive structure proper ties during preliminary training to evaluate the outcome of this intervention on a new learning task. The studies reviewed tended to support the conclusion that cognitive structure variables influence learning and retention. CHAPTER III METHODOLOGY Since the purpose of the present study was to clarify the functioning and effectiveness of the use of advance organizers, the methodological procedures were devised to compensate for certain limitations in the original work (Ausubel, 1960). Specifically, four major points were involved which have been cited in the previous chapter. To recapitulate, they were: 1. Inadequate control of the possible direct contribution of the organizer by itself to the criterion measure. 2. Failure to satisfy the criterion of unfamil- iarity of material to subjects. 3. Inequity in the number of learning trials between the experimental and control groups. 4. Lack of distinction between learning and reten tion. 32 33 In response to these items, the present study employed three treatment groups, whose purpose will now be explained. Control of Direct Contribution by the Advance Organizer In order to control for possible direct transfer by the organizer, two of the treatment groups received it, however, in different sequences. One group was given the organizer prior to receiving the learning passage and the other group was given the organizer after the learning passage. Both groups were then given the criterion test. If, as it was argued by Ausubel, the organizer functioned only by means of its organizational properties and not by means of direct transfer, then this second group should be distinguishable from the first in terms of its lower criterion score. The subsuming properties of the organizer would have been obviated by the learner's reliance on already existing concepts in cognitive struc ture which would not be as clear, stable, and abstract as those provided by the prior introduction of the organizer. On the other hand, if there were no differences between the criterion test scores, then it could be assumed that the organizational properties of the 34 organizer were insignificant in conferring an advantage on the experimental group, which experienced the sequence of organizer, learning passage then criterion test. Meeting the Criterion of Unfamiliarity of the Learning Material to the Subjects To meet the requirement that the learning material be equally unfamiliar to all, the subjects were randomly assigned to one of the three groups. This procedure nullified the need to test for degree of familiarity of the learning passage since subjects with any prior knowl edge regarding the metallurgical properties of steel could be assumed to be equally distributed throughout the three treatment groups. Hence, any prior information would be randomly reflected in their criterion test scores. The process of randomization would also eliminate systematic error resulting from individual differences among the subjects such as major area of study, age, sex, class, and reading comprehension. To this point Edwards states: If we use a sufficiently large number of sub jects, we hope that the randomization process will provide an adequate control with respect to the various organismic variables that might influence the outcome of the experiment in that differences between the two treatment groups with respect to these variables should represent only chance or random differences and not systematic differences. (1968:65) 35 Equating the Number of Learning Trials Two of the three treatment groups received the advance organizer. Since the number of learning trials was the same, then the demands posed by the total time hypothesis were satisfied. Thus, any significant differ ences in criterion test scores in favor of the experimental group could not be questioned in terms of greater learning trials or time allowed for study. Distinguishing Between Learning and Retention Regarding the distinction between learning and retention, the criterion test was given to all subjects twice, once immediately after exposure to the learning passage and then again one week later. Hence, it was possible to assess differences in initial learning from differences in retention. Null Hypotheses The experimental procedure that will be detailed below was designed to test the following hypotheses at the 0.05 level of significance. Hypothesis 1.— There is no significant difference in initial learning as measured by the criterion multiple- 36 choice test among the three treatment groups. Hypothesis 2.— There is no significant difference in the retention of learning as measured by the criterion multiple-choice test among the three treatment groups. Subjects The subjects used in this study were 51 under graduate students at the California State College at Los Angeles enrolled in a general psychology course as part of a humanities sequence required for the bachelor of arts degree. They constituted a heterogeneous group in terms of age, ranging from 18 to 51 years with the mean being 22 years. As might be expected, all undergraduate class levels were represented as were major departments of study. The subjects participated in the experiment as a required part of their course work. Apparatus The apparatus consisted of the original material used by Ausubel in his 1960 study. It was comprised of four separate sets of printed material. These were the advance organizer, the historical passage, the learning passage, and the criterion test. 37 Hie advance organizer (the independent variable) consisted of approximately 500 words and contained back ground information for the passage to be learned. This passage presented the information at a much higher level of abstraction, generality and inclusiveness than the learning passage itself. The main emphasis was placed on the major similarities and differences between metals and alloys, their respective advantages and limitations, and their uses. It was designed to exclude specific informa tion which could contribute directly to the criterion test scores. The control introductory passage, also about 500 words in length, consisted of historical facts relative to the development of the present methods used in steel production. In contrast to the advance organizer, it contained no concepts that could afford "ideational anchorage.* The passage to be learned, especially prepared by Robert M. Tomlinson, dealt with the metallurgical proper ties of steel. It consisted of 2,500 words and emphasized such basic principles as the relationship between metallic grain structure, on the one hand, and temperature, carbon 38 content, and rate of cooling on the other. Additional important information was covered, including the techno logical processes of heat treatment and tempering. The dependent variable was a 42-item multiple- choice test with a split-half reliability of .79. It included items covering principles, facts, and their applications to the production of various types of steel alloys. Since it was used as a power test, no time limit was imposed. For specimens of the experimental material, refer to the Appendix. Procedure For a diagrammatic representation of the experi mental procedure, refer to Figure 2. Prior to the actual experimental procedures, all subjects were given the following information: "Today you will be the subjects in an experiment on learning. I cannot tell you any more at this time but after the experiment is over I will be glad to explain it and answer any questions that you have. Now I will divide you into three equal groups." Treatment Group I Treatment Group II Treatment Group III Phase 1 Learning Passage Historical Passage Advance Organizer Phase 2 Advance Organizer Learning Passage Learning Passage Phase 3 Criterion Test (given immediately and one week later) Criterion Test (given immediately and one week later) Criterion Test (given immediately and one week later) Figure 2.— The Experimental Procedure 40 The subjects were separated randomly into three approximately equal groups with each group occupying one of the three sections in the lecture hall. The left section (relative to the experimenter) seated treatment group 1^ the center section, treatment group II; and the right section, treatment group III, the experimental group. All subjects were then told: "You will be receiving several written passages during the period. Leave these papers face down until you are told otherwise." Beginning with treatment group I, the learning passage was passed out, face down. The subjects in this group were then told to turn the papers over and to read the instructions silently while the experimenter read them aloud. The directions were: "This is a test of how well you can learn the substance and details of typical scientific material at the college level. "When I give the signal, turn this page and read the entire selection at your customary reading speed. During the first reading, concentrate on grasping the general features of the material and becoming generally familiar with it. During the remainder of the available 41 time, use whatever method you prefer to fix the substance and details of the selection in your memory, but do not take any notes or make any marks on the reading material. "You will be examined on this material by means of a multiple choice test. The ability to provide correct answers to these questions will presuppose adequate com prehension of the material as well as precise knowledge of the details. You will have an opportunity before the end of the semester to learn both your own score and the range, distribution and central tendency of scores for the entire class." This group's beginning time was noted and the experimenter's attention was directed to the remaining subjects. The identical procedure used in passing out the material for treatment group I was then used for giving treatment group II and treatment group III their respec tive introductory passages. Their directions were: "This is some introductory background material pertaining to a more detailed selection in the same general subject-matter area that you will be studying shortly. You will have 5 minutes in which to study this introductory material." "When I give the signal, turn this page and read the entire selection at your customary reading speed. During the first reading, concentrate on grasping the general features of the material and becoming generally familiar with it. During the remainder of the available time, use whatever method you prefer to fix the substance and the details of the selection in your memory, but do not take any notes or make any marks on the reading material." After 5 minutes, the introductory passages were collected from the two groups and the learning passage disseminated. The group was given the same instructions which had been previously given to treatment group I. Treatment group I was informed to stop reading and their learning passages were collected after its allotted 35 minutes had elapsed. The advance organizer was then passed out with the appropriate instructions. After 5 minutes, the selections were collected from all sections. At this point the multiple choice criterion test was passed out and the following directions were read aloud to the subjects: "The questions on the following pages test your knowledge of the material that you studied recently. "These questions are all of the multiple-choice 43 type. For each question choose the lettered alternative that is most appropriate. If two or more answers seem appropriate, choose the one that seems most correct to you. Only one answer should be chosen for each question. Answer all questions even if you do not feel completely certain of your answer in a particular case.” "When you have decided which of the five-lettered answers is correct for each question, block in the cor responding space on the answer sheet with pencil or pen. Make sure that the number of each question you answer on the answer sheet corresponds to the same numbered question on the question sheet. You can avoid errors by answering each question as you come to it. Do not skip around from one question to another. You should place your name, age, sex, the date, major and the instructor's name in the appropriate places on the answer sheet." "Please make no marks on the question booklet." The subjects were allowed ample time to finish the test, which was again administered exactly one week later. The second administration was to observe any differences in retention of the material as a function of the differ ent treatments. Because of absences of subjects at the times of the two experimental sessions, the final number 44 of complete data subjects turned out to be 51. Statistical Analysis Since prior research (Ausubel, 1960, 1961) has indicated that the effectiveness of the organizer is related to the learner's academic ability, Scholastic Aptitude Test scores were obtained from most of the sub jects' admissions records. Even though scores did not exist for all the students, a sufficient number was obtained in order to allow for any variance among treat ment groups to be evaluated in the light of initial differences in verbal, quantitative and total SAT scores. Hence, the data were treated by means of analysis of co- variance, with the dependent variables being the first and second criterion test score which measured the amount of initial learning and amount of retention, respectively. The covariants were SAT verbal, quantitative and total test scores. CHAPTER IV RESULTS This chapter will present the results of the study in two major sections. Hie first half will dealy with the outcomes concerning hypothesis 1 and the second half will pertain to hypothesis 2. Hypothesis 1— Initial Learning The research hypothesis stated: The initial learning of unfamiliar material preceded by an advanced organizer is superior to the condition in which the material is preceded by an irrelevant historical passage or if followed by an advance organizer. The null hypothesis stated: There is no signifi cant difference in initial learning as measured by the criterion multiple-choice test among the three treatment groups. Table I shows the sample size, means, and standard deviations for all three treatment groups for the amount of initial learning. Tables II-IV present results for 45 46 TABLE I SAMPLE SIZE, MEANS, AND STANDARD DEVIATIONS FOR ALL THREE TREATMENT GROUPS FOR INITIAL LEARNING Group Sample Size Mean Standard Deviation I 21 15.29 5.35 II 17 17.29 6.75 III 13 15.15 5.40 hypothesis 1. The treatment of the data was by means of analysis of covariance, with SAT verbal, quantitative and total test scores being the covariants. Table II summarizes the results of the analysis of covariance for initial learning with the Scholastic Aptitude Test— verbal scores as the covariants. The obtained F value, 1.011, does not approach the present .05 level of significance. Thus, the null hypothesis is tenable. Table III is a summary table for the analysis of covariance for initial learning with the Scholastic 47 TABLE II ANALYSIS OF COVARIANCE FOR SCHOLASTIC APTITUDE TEST VERBAL SCORES FOR INITIAL LEARNING Source of Variance Sums of Squares Degrees of Freedom Mean Square F Ratio Adjusted Means 55.3 2 27.63 1.011a Error within Groups 1284.5 47 27.33 Total 1339.7 49 ‘ ‘ Not significant. TABLE III ANALYSIS OF COVARIANCE FOR SCHOLASTIC APTITUDE TEST QUANTITATIVE SCORES FOR INITIAL LEARNING Source of Variance Sums of Squares Degrees of Freedom Mean Square F Ratio Adjusted Means 0.4 2 0.18 0.006a Error within Groups 1389.0 47 29.55 Total 1389.4 49 ^ot significant. 48 Aptitude Test— quantitative scores as the covariants. Hie obtained F value, 0.994, is not significant. Hence, the null hypothesis is supported. Table IV shows the value for the analysis of covariance for initial learning with the Scholastic Aptitude Test-total scores as the covariants to be 0.046. This value is not significant, and thus the null hypoth esis is accepted. TABLE IV ANALYSIS OF COVARIANCE FOR SCHOLASTIC APTITUDE TEST TOTAL SCORES FOR INITIAL LEARNING Source of Variance Sums of Squares Degrees of Freedom Mean Square F Ratio Adjusted Means 2.2 2 1.11 0.046a Error within Groups 1358.8 56 24.26 Total 1361.0 58 ^ot significant. 49 Hypothesis 2-"Retention The research hypothesis stated: The initial retention of the newly assimilated material when it is preceded by an advance organizer is greater than when the material is preceded by a historical passage or followed by an advance organizer. The null hypothesis stated: There is no signifi cant difference in the retention of learning as measured by the criterion multiple-choice test among the three treatment groups. Table V presents the sample sizes, means, and standard deviations for all three treatment groups for the amount of retention. TABLE V SAMPLE SIZE, MEANS, AND STANDARD DEVIATIONS FOR ALL THREE GROUPS FOR RETENTION Group Sample Size Mean Standard Deviation I 18 15.94 5.33 II 14 16.71 6.66 III 11 15.55 3.50 50 Tables VI-VIII present results for hypothesis 2. Table VI presents a summary of the analysis of covariance for retention with the Scholastic Aptitude Test— verbal scores as the covariants. It can be seen that the obtained F value of 0.151 is not significant at the .05 level. Hence, the null hypothesis is accepted. TABLE VI ANALYSIS OF COVARIANCE FOR SCHOLASTIC APTITUDE TEST VERBAL SCORES FOR RETENTION Source of Variance Sums of Squares Degrees of Freedom Mean Square F Ratio Adjusted Means 7.8 2 3.92 0.151a Error within Groups 1014.9 39 26.02 Total 1022.7 41 ^ot significant. 51 Table VII displays the analysis of covariance for retention with the Scholastic Aptitude Test— quantitative scores as the covariants. The obtained F of 1.636 is not great enough to reject the null hypothesis. TABLE VII ANALYSIS OF COVARIANCE FOR SCHOLASTIC APTITUDE TEST QUANTITATIVE SCORES FOR RETENTION Source of Variance Sums of Squares Degrees of Freedom Mean Square F Ratio Adjusted Means 60.4 2 30.18 1.636 Error within Groups 719.5 39 18.45 Total 779.8 41 ^ot significant. Finally, Table VIII summarizes the analysis of covariance for retention with the Scholastic Aptitude Test— total scores as the covariants. It is apparent that the F value of 0.672 is insufficient for the rejection of the null hypothesis, hence, it is tenable. 52 TABLE VIII ANALYSIS OF COVARIANCE FOR SCHOLASTIC APTITUDE TEST TOTAL SCORE FOR RETENTION Source of Variance Sums of Squares Degrees of Freedom Mean Square F Ratio Adjusted Means 14.9 2 7.46 0.409a Error within Groups 893.6 49 18.24 Total 908.6 51 ®Not significant. The meaning of this failure to obtain results congruent with Ausubel's theory will be discussed in the next chapter. CHAPTER V SUMMARY, DISCUSSION AND CONCLUSIONS Summary Problem The purpose of this study was to investigate the possibility that advance organizers bestow favorable effects in the learning and retention of unfamiliar meaningful verbal material. In two earlier researches, Ausubel (1960, 1961) had demonstrated support for this possibility, however, not conclusively. Therefore, the present study was a replication of Ausubel's 1960 work but differed from it in terms of compensating for limitations contained in the original investigation. Specifically, the experimental method was devised to (1) control the possible direct contribution of the organizer alone to the criterion measure} (2) satisfy the criterion of unfamiliarity of the learning material to the subjects; (3) equate the number of learning trials among the groups; and 53 54 (4) distinguish between learning and retention. Procedure Fifty-one subjects, who were enrolled in a general psychology class at California State College at Los Angeles participated in the study. Subjects were randomly assigned to one of three treatment groups. The experiment consisted of exposing treatment group I to the sequence of a learning passage, advance organizer, then criterion test; treatment group II to the sequence of historical passage, learning passage, then criterion test; and treatment group III to the sequence of advance organizer, learning passage and criterion test. After one week had elapsed, the criterion test was again given to all groups in order to assess the amount of retention of the newly learned material. Findings The findings derived from an analysis of the data, which supported the null hypotheses, may be sum marized in the following manner: 1. There was no significant difference in initial learning as measured by the criterion multiple- 55 choice test among the three groups. 2. There was no significant difference in the reten tion of the learning as measured by the criterion multiple-choice test among the three groups. Discussion Except for the one instance where a comparative organizer proved significantly effective on immediate testing, none of the other studies concerning the use of expository advance organizers has confirmed their efficacy in enhancing the learning and retention of unfamiliar meaningful verbal material. In both of Ausubel's (I960, 1961) previous studies, inadequate experimental design had resulted in equivocal interpretations of the results relative to his subsumption theory of meaningful learning. These shortcomings were: 1. Inadequate control of the possible direct con tribution of the organizer alone to the criterion measure. 2. Failure to satisfy the criterion of unfamiliarity. 3. Inequity in the number of learning trials. 4. Lack of distinction between learning and retention. 56 The present replication also failed to produce findings confirming the theory in spite of attending to the above limitations. Perhaps the nature of the experimental situation, being unlike that in which the learner usually studies, interfered with their mastery of the organizer, especially since adaptation to the situation was minimal being that this passage was presented at the beginning of the experiment. V. P. Duncan (1959) and Morrisett and Hovland (1959) state that prior learnings are not transferable to new tasks until they are first overleamed. According to Ausubel: Overlearning in turn, requires an adequate number of adequately spaced repetitions and reviews, sufficient intra-task repetitiveness prior to intra- and inter-task diversification and opportunity for differential practice of the more difficult com ponents of the task. Frequent testing and provision of feedback, especially with test items demanding fine discrimination among alternatives varying in degree of correctness, also enhance validation by confirming, clarifying, and correcting previous learnings. (1968) As the reader is aware, none of the above events was permitted by the present experimental design. Hence, it is arguable that the degree of assimilation of the organizers was inadequate, especially in the face of a difficult criterion test of the type described in the 57 above quotation. Another possible issue is whether one brief organizer Desson can have a measurable effect in terms of the amount of prior learning experienced by the individual. Even though present, the influence of the organizer may be insignificant in the face of other sources of vari ability. If this is true, then the problems raised in terms of experimental design would become immense. Conclusions With the foregoing considerations in mind, that the subjects learn the advance organizer with sufficient repetition, one cannot fail to consider the possibility that organizers provide nothing more than proactive facilitation in regards to learning and retention. It appears that the organizational influence of organizers on cognitive structure remains to be demonstrated. Studies by Ausubel (1960, 1961) produced ambiguous results. The only additional researches, prior to the present one, failed to show the efficacy of organizers in meaningful verbal learning and retention (Schulz, 1966j Wulf, 1971). The present replication, modified to render maximum control, also failed to confirm the experimental 58 hypotheses. Hence, it seems reasonable to conclude that serious questions are raised about the nature of organizers in meaningful verbal learning which in turn leads to the requirement for further inquiry into the theory itself. REFERENCES 59 REFERENCES Anderson, R. C. Educational psychology. Annual Review of Psychology, 18, 1967. Ausubel, David P. The use of advanced organizers in the learning and retention of meaningful verbal material. Journal of Educational Psychology, 51, 1960, 267-272. Ausubel, David P., and Fitzgerald, Donald. The role of discriminability in meaningful verbal learning and retention. Journal of Educational Psychology, 52, 1961, 266-274. Ausubel, David P. Educational psychology; a cognitive view. New York: Holt, Rinehart and Winston, 1968. Bruner, J. S. Going beyond the information given. Contemporary Approaches to Cognition. Cambridge, Mass.: Harvard University Press, 1957, 41-70. Bugelski, B. R. Presentation time, and mediation compared-associate learning. Journal of Educa tional Psychology, 63, 1962, 409-412. Duncan, C. P. Transfer in motor learning has a function of degree of first-task learning and intra-task similarity. Journal of Experimental Psychology, 45, 1953, 1-11. Duncan, C. P. Recent research on human problem solving. Psychological Bulletin, 56, 1959, 397-429. Edwards, Alan L. Experimental design in psychological research. New York: Holt, Rinehart, and Winston, 60 61 French, R. S. The effect of instructions on the length- difficulty relationship for a task involving sequential dependency. Journal of Experimental Psychology, 48, 1954, 89-97. Haselrud, J. M. Transfer from context by sub-threshold summations. Journal of Educational Psychology, 50, 1959, 254-258. Henrickson, G., and Schroeder, W. H. Transfer of training in learning to hit a submerged target. Journal of Educational Psychology, 32, 1941, 205-213, Hildard, £. R.; Irvine, R.D.? and Whipple, J. E. Rote memorization, understanding, and transfer: an extension of Katona's card trick experiments. Journal of Experimental Psychology, 46, 1953, 288-292. Judd, C. H. Practice and its effects on the perception of illusions. Psychological Review, 9, 1902, 27-39. Katona, D. Organizing and memorizing. New York: Columbia University Press, 1940. Kendler, H. H., and Karasik, A. B. Concept formation as a function of competition between response- produced views. Journal of Experimental Psychology, 55, 1958, 278-283. Marks, L. E., and Miller, G. A. The role of semantics and syntactic constraints in the memorization of English sentences. Journal of Verbal Learning and Verbal Behavior, 3, 1964, 1-5. Matthews, R. Recall of a function of number of classifi- tory items. Journal of Experimental Psychology, 47, 1954, 241-247. Meredith, Charles Earling. Development of problem solving skills in high school physical science. Unpub lished Doctoral Dissertation, Stanford University, 1961. 62 Morrisett, L., and Hovland, C. I. A comparison of three kinds of training in human problem solving. Journal of Experimental Psychology, 58, 1959, 52-55. Newton, ^ p., and Hickey, Albert E. Sequence effects in frammed learning of the verbal concept. :al of Educational Psychology, 56, 1965, 145-147. Osgood, C. E. Method and theory in experimental psychol ogy. New York: Oxford University Press, 1953. Overing, R. L. R., and Travers, R. M. W. Effect upon transfer of variations in training conditions. Journal of Educational Psychology, 57, 1966, 179-188. Paul, I. H. Studies in remembering: the reproduction of connected and extended verbal material. Psycholog ical Issue, 1, No. 2. New York: International University Press, 1959. Postman, L. Learned principles of organization in memory. Psychological Monograph, 68, 1954. Poulton, E. C. Previous knowledge and memory. British Journal of Psychology, 48, 1957, 259-270. Pubols, B. H. Successive discrimination learning in the white rat: a comparison of two procedures. Journal of Comparative Physiological Psychology, 50, 1957, 319, 322. Reed, L. S. The development of non-continuity behavior through continuity learning. Journal of Experimental Psychology, 46, 1953, 107-112. Reynolds, J. H. Cognitive transfer in verbal learning. Journal of Educational Psychology, 57, 1966, 382-388. 63 Sassenrath, J. M. Learning without awareness in transfer of learning steps. Journal of Educational Psychology, 50, 1959, 205-211. Schultz, R. W. The role of cognitive organizers in the facilitation of concept learning in elementary school science. Unpublished Doctoral Disserta tion, Purdue University, 1966. Schwartz, F., and Lippman, Frances. Cognitive and asso ciate structures in recall. Psychological Reports, 11, 1962, 91-101. Staats, Karolyn, Spaats, A. W., and Schutz, R. E. The effect of discrimination pretraining on textural behavior. Journal of Educational Psychology, 53, 1962, 32-37. Watkins, Ralph K. Instruction in physical science in the secondary school. A Program for Teaching Science, 1932, 243-248. The Thirty-first Yearbook of the National Society for the Study of Education, Part I. Bloomington, 111.: Public School Pub lishing Co. Wulf, Kathleen M. Proactive effects in meaningful verbal learning and retention in eighth grade students. Unpublished Doctoral Dissertation, University of Southern California, 1971. APPENDIX 64 THE ADVANCE ORGANIZER 65 66 DIRECTIONS This is some introductory background material pertaining to a longer and more detailed selection in the same general subject-matter area that you will be studying shortly. You will have five minutes in which to study this introductory material. When I give the signal, turn this page and read the entire selection at your customary reading speed. During the first reading, concentrate on grasping the general features of the material and becoming generally familiar with it. During the remainder of the available time, use whatever method you prefer to fix the substance and the details of the selection in your memory, but do not take any notes or make any marks on the reading material. 67 METALS AND ALLOYS Metal has certain unique advantages over other substances as a material for tools and implements. It is hard, strong, durable, and can be molded to any desired shape. When no longer required for a particular use it can be melted and made into a new product. But even more important, perhaps, is the fact that it has a wide divers ity of properties under the control of man. Many important physical properties of metal depend upon its internal grain structure. We cam, therefore, alter the properties of a given metal by changing its internal structure. Both heat and various mechanical processes modify the internal structure and hence the properties of metals. Heat, for example, changes the grain structure of metals in such a way as to soften them, and hammering at room temperature changes their grain structure in such a way as to harden them. Nevertheless, despite the possibility of modifying the internal structure of metals by heat and mechanical means, the range of properties available among pure metals is obviously limited by the existence of only a small number of pure metals. Hence, if man restricted himself 68 to the use of pure metals he would only have a limited variety of grain structures and a correspondingly limited range of physical properties at his disposal. It is true, of course, that pure metals do have certain unique functions that alloys cannot perform, especially in laboratory instruments. F^r most practical purposes, however, it is expedient to alloy a metal with other metals or non-metals, and thus take advantage of the much wider selection of grain structures and physical properties which thereby becomes available. Generally speaking, other elements are alloyed with metals to confer such properties as increased hardness, strength, toughness and flexibility. Almost any desired combination of physical properties can be developed to meet the specific requirements of a metal part by selecting an appropriate metal, by choosing suitable kinds and percentages of alloying elements, and by subjecting the resulting alloy to appropriate mechanical and/or other procedures. It is clear from the foregoing, therefore, that the properties of a given alloy, like those of a pure metal, are (within certain limits) determined by its distinctive grain structure. This structure in turn depends upon the particular metal and the specific type 69 and amount of alloying substance used. Alloys also resemble pure metals in the fact that their internal structure also varies with temperature. Unlike pure metals, however, the grain structure (and hence the properties) of some alloys are modified by the rate at which they are cooled. Hence, before we could predict the grain structure and properties of an alloy belonging to the latter category of alloys, we would not only have to know (a) its temperature and (b) its principal metal component, and the type and amount of alloying substance used, but also (c) the rate at which it was cooled. THE HISTORICAL PASSAGE 71 DIRECTIONS This is some introductory background material pertaining to a longer and more detailed selection in the same general subject-matter area that you will be studying shortly. You will have five minutes in which to study this introductory material. When I give the signal, turn this page and read the entire selection at your customary reading speed. During the first reading, concentrate on grasping the general features of the material and becoming generally familiar with it. During the remainder of the available time, use whatever method you prefer to fix the substance and the details of the selection in your memory, but do not take any notes or make any marks on the reading material. 72 IRON AND IRON ALLOYS Iron and iron alloys have a long and interesting history* The wide range of iron derivatives available today occupies an intermediate position in both time and complexity between the ancient art of the metalsmiths and our modem science of metallurgy. Although modern methods of mass-producing iron and iron alloys are only about one hundred years old, iron products have been used for about 4,000 years, and many of the basic processes employed today are several hundred years old. Meteoric iron was probably^ the first iron alloy used by man in most parts of the world. This type of iron accounts for the ex£*lte^ce of many iron tools in areas where iron smelting was unknown. It has a high nickel content peculiar to meteoric iron; no known iron ore shares this characteristic. Although this alloy could not be melted with charcoal fires, it could be softened and formed into tools far superior to those of bronze or copper. Wrought iron was in use before the first written records and was the primary iron product made by man until about 100 years ago. It is almost pure iron that contains 73 strips and pieces of slag throughout, and is fairly strong and easy to work. Wrought iron was produced in a crude charcoal- burning furnace similar to that used in the refining of copper and tin. Wood charcoal and ore were placed in the tube-like furnace, and the charcoal was ignited from the bottom. The natural draft of air in such a furnace, however, was insufficient for the charcoal to burn fast enough to produce the necessary heat and temperature. To overcome this difficulty, the furnace was made higher and hand-operated bellows were used to increase the available air flow. Although this type of furnace was hot enough to melt tin and copper ores, it was not hot enough to reduce iron ore to a molten (liquid) state. Almost any desired combination of physical properties can be developed to meet the specific requirements of a metal part by select ing an appropriate metal, by choosing suitable kinds and percentages of alloying elements, and by subjecting the resulting alloy to appropriate mechanical and/or other procedures. It is clear from the foregoing, therefore, that the properties of a given alloy, like those of a pure 74 metal, are (within certain limits) determined by its distinctive grain structure. This structure in turn depends upon the particular metal and the specific type and amount of alloying substance used. Alloys also resemble pure metals in the fact that their internal structure also varies with temperature. Unlike pure metals, however, the grain structure (and hence the properties) of some alloys are modified by the rate at which they are cooled. Hence, before we could predict the grain structure and properties of an alloy belonging to the latter category of alloys, we would not only have to know (a) its temperature and (b) its principal metal component, and the type and amount of alloying substance used, but also (c) the rate at which it was cooled. THE LEARNING PASSAGE 75 76 DIRECTIONS This is a test of how well you can learn the substance and details of typical scientific material at the college level. When I give the signal, turn this page and read the entire selection at your customary reading speed. During the first reading, concentrate on grasping the general features of the material and becoming generally familiar with it. During the remainder of the available time, use whatever method you prefer to fix the substance and details of the selection in your memory, but do not take any notes or make any marks on the reading material. You will be examined on this material by means of a multiple choice test. The ability to provide correct answers to these questions will presuppose adequate com prehension of the material as well as precise knowledge of the details. You will have an opportunity before the end of the semester to learn both your own score and the range, distribution and central tendency of scores for the entire class. 77 THE PROPERTIES OF PLAIN CARBON STEEL Steel as an Alloy An alloy is a metallic substance obtained by combining two or more elements at least one of which is a metal. Depending on its temperature it may be either a solution of its constituent elements or a homogeneous mixture resulting from the cooling of such a solution. When examined under a powerful microscope it is found to have a uniform internal structure from one portion to another. If a metal merely contains other elements, for example, impurities, embedded within it nonhomogeneously in scattered pockets or inclusions, it is not considered an alloy. Most alloys, however, do contain small residual percentages of impurities, usually derived from the metal ore, which are not completely removed by the refining process. In these instances the amount of impurities in the alloy is so small that it does not materially impair the usefulness of the metal. Complete removal of all impurities is not feasible because of the prohibitive expense of such a procedure. 78 A relatively simple metallic grain structure is predictable as long as the constituent elements of an alloy do not interact chemically. The grains resulting from the cooling of a solution of bronze (an alloy of copper and tin), for example, are metallic grains compare able to grains of pure metal except for having two metal lic constituents instead of one. All of the grains are alike: each grain is a grain of bronze. And although the copper and tin components of the grain are not chemically united they are no longer distinguishable as separate metals. A somewhat different situation prevails when the constituent elements of an alloy enter into chemical com bination. In the case of steel (an alloy of iron and carbon), for example, carbon and small amounts of iron interact chemically forming a compound of the two elements (iron carbide), and particles of this compound are then uniformly dispersed among the grains of metal. Thus, we do not have a solution or homogeneous mixture of a simple type of metallic grain such as bronze, the components of which are indistinguishable from each other. He have instead a solution or homogeneous mixture of two struc turally distinct and identifiable components, namely. 79 metallic grains (iron) and particles of an iron-carbon compound (iron carbide) distributed within and around the grains of iron. This opens up a whole new variety of more complex grain structures that cannot be achieved in the case of simple metallic grain alloys and/or pure metals, thereby making possible such procedures as hardening by * "heat treatment." Of all the thousands of alloys, only iron alloys containing small amounts of carbon, and certain alloys of magnesium and aluminum may be "heat treated." For our purposes, steel may be defined as an alloy of iron with a small percentage of carbon, usually from 0.10% to 1.5%, but never more than 2%. It may also contain one or more other alloying elements (in addition to carbon) to confer such properties as increased hardness, strength, toughness, flexibility, and resistance to corrosion. But most steel made today, as well as most steel in use, is plain carbon steel. RELATION OF INTERNAL STRUCTURE OF STEEL TO TEMPERATURE The properties of steel vary with its temperature. The most obvious property change related to a change in temperature is the transition from a solid to a liquid 80 state as steel is heated above its melting point. The reverse transition occurs when molten (liquid) steel is cooled below its melting point and solidifies into grains (crystals), much like water freezing into ice. At normal atmospheric temperatures, the grains of iron and the iron carbide particles in solid steel are fixed in position, that is, immobilized in a definite structural arrangement. As heat is applied to this steel, however, many changes in internal structure take place while it is still in the solid state and below the melting temperature. Generally such changes take place at defi nite temperatures known as "critical temperatures." Solid steel at high temperatures (i.e., above its upper critical temperature) is actually a solid solution. It may seem odd to think of a solid material as being a solution. Yet steel, while in the solid state below the melting point but above its upper critical temperature, has a uniform internal structure that varies within wide limits. This is the definition of a solution. Glass is probably the best known solid solution. Characteristic of steel as a solution (liquid or solid), therefore, is its variability of internal struc ture. The iron carbide breaks up into tiny, hard and 81 brittle particles which more or less float throughout the grains of iron. The particles have a great amount of freedom to form and reform, change size and relationship to each other, and otherwise rearrange themselves; at any given temperature they assume the size, shape and rela- tionship most normal at that temperature. As steel cools through its lower critical temperature and ceases to be a solid solution, this freedom is lost and its internal structure becomes fixed or invaried)le. The lower critical temperature of steel is that temperature at which the carbide starts going into solu tion when steel is heated. As the temperature is raised, more and more carbide goes into solution. Hie upper critical temperature represents the point at which all carbide present in the steel is in solution. The lower critical temperature is always the same for all carbon steels, namely, 1350* F. The upper critical temperature, however, decreases as the carbon content increases. It decreases from 1600® F. for 9.10% carbon to 1350° F. for 0.80% carbon. Thus, for 0.80% carbon steel (and above), the upper and lower critical temperatures are the same, and all of the carbide goes into solution at 1350®. When less than 0.80% carbon is present, the carbide in steel 82 is only partially in solution between the upper and lower critical temperatures. Beyond 0.80% carbon, greater carbon content in steel does not lower the upper critical temperature below 1350® F. RELATION OF INTERNAL STRUCTURE OF STEEL TO ITS CARBON CONTENT The second important factor that determines the internal structure of steel is the amount of carbon (in the form of carbide) it contains. At 0.80% carbon (and below), all of the carbide is located vithin the grains of iron. If steel contains 0.80% carbon, sufficient carbide is available to saturate all of the iron grains. In 0.40% carbon steel, one-half of the grains are satu rated with carbide; the remaining half are grains of pure iron. In 0.20% carbon steel, one-quarter of the grains are saturated with iron carbide and three-quarters of the grains are pure iron. Intermediate amounts of carbon are distributed proportionately. Any amount of carbon over 0.80% also saturates all of the iron grains with iron carbide particles; the excess carbide forms a shell-like layer around the grains. Since the tiny carbide particles are extremely 83 hard, the higher the carbon content of the steel is, the harder the steel will be. This statement is unequivocably true up to 0.80% carbon steel. Above this figure, the relationship between the carbon content of steel and its hardness depends on the rate at which it is cooled. (This will be discussed further below.) RELATION OF INTERNAL STRUCTURE OF STEEL TO RATE OF COOLING The precise type of fixed internal structure that steel assumes as it changes from a solid solution, while passing through its upper and lower critical temperatures, depends on the rate at which it is cooled through these tempe ra tures. In the solid solution condition, as already pointed out, the carbide particles in steel are mobile, almost floating, and are free to rearrange themselves in a manner most normal for a particular temperature. When the metal is cooled through its upper and lower critical temperatures, however, the carbide assumes a fixed size and position in and around the iron grains. If a solid solution of steel is cooled slowly through its two criti cal temperatures, the carbide particles have sufficient 84 time to rearrange themselves and thus become fixed in an orderly structure natural for lower temperatures, if cooled rapidly, on the other hand, sufficient time is not available for this orderly and normal rearrangement to take place, and the resulting fixed structure is strained and unnatural. Slow Cooling It is clear, therefore, that when a piece of steel is cooled very slowly through its critical temperatures, it assumes a natural and unstrained internal structure. The carbide particles have time to collect into spheres within all or some grains and into layers around the grains depending on whether the percentage of carbon in the steel is 0.80%, or below or above this figure. (How the internal structure varies with the amount of carbon in steel, has already been described in a previous section.) When plain carbon steel is heated above its critical temperatures and then cooled slowly, the natural internal structure it assumes makes it relatively soft and tough. Hence, steel treated in this fashion is quite easily formed, but by the same token is also easily bent 85 or stretched without cracking or breaking. Hie carbide spheres do have some influence, however, since higher carbon steels emerge slightly harder than lower carbon steels from the same slow-cooling procedure. This rela tionship between carbon content and hardness holds true even beyond 0.80% carbon in the case of slow-cooled steels. When 1.2% carbon steel is cooled slowly, for example, it becomes slightly harder than when 0.90% carbon steel is cooled slowly. Rapid Cooling Rapid cooling of steel from a solid solution traps the tiny carbide particles in a fixed structure before they have time to reform and collect in spheres within, and in layers around the grains of iron. Faster and faster cooling results in the carbide being trapped in a fixed condition in ever finer particles more completely dispersed within the iron grains. This particular un natural structure makes for greater and greater hardness and brittleness, which properties also increase propor tionately with the amount carbon present, up to 0.80% carbon. At this point maximum hardness is achieved. Rapidly cooled 1.0% carbon steel, for example, is not 86 harder than rapidly cooled 0.80% carbon steel. If a piece of steel is cooled through its critical temperatures in less than one second, the carbide parti cles are trapped in a completely dispersed structure. This is a spiny, needle-like network resembling pine leaves. The spines act as interlocking reinforcing rods do in concrete, locking the iron grains in a very hard, rigid arrangement. The higher the carbon content (up to 0.80%), the more spines, and consequently the greater hardness. High carbon steel treated in this way is very hard and brittle— even more brittle than glass. It will break before bending. This process of hardening steel by first heating it above its critical temperatures, and then taking advantage of the particular unnatural internal structure that develops as it is cooled rapidly through these temperatures, is known as "heat treatment." Steel is one of the few alloys that can be hardened by heat treatment. It should be borne in mind, however, that heat treatment accomplishes nothing in the way of hardening unless the carbide is first in solution. This only begins to occur above the lower critical temperature. Hence, even very rapid cooling from any temperature less than 1350° F. 87 will not increase hardness. Although excess carbon beyond 0.80% does not increase the hardness of "hardened" steel, it does serve a useful purpose by increasing the wear resistance of such a piece. In wearing away this piece of steel, one would have to wear down both the hard grains of steel as well as the much harder layers of carbide particles around each grain. A major disadvantage of high carbon steels, how ever, is the fact that the brittle shell of iron carbide around the iron grains increases brittleness. Hence, these steels are more likely to fracture on impact or bending than tougher low carbon steels. An important complieating factor in heat treatment arises from the fact that steel is chemically more active at high temperatures. If it is heated in an ordinary air, oxygen actually bums carbon out of the surface of the steel, thereby lowering its carbon content. Atmospheric oxygen also oxidizes (i.e., rusts) the iron itself at a very rapid rate when steel is hot. If heated in an atmosphere of carbon gases, on the other hand, steel absorbs carbon into its surface. Special precautions, therefore, must be taken to prevent oxidation, burning out of carbon, or the absorption of carbon while finished 88 parts are heat treated. In some instances, however, a finished part (made of low carbon steel) may be delib erately heated in sun atmosphere of carbon gases so that it may absorb carbon and thus acquire a hard outer case. Tempering Hardness alone is seldom desired in a piece of steel. Any given piece must have the most desirable com bination of properties possible for its particular use— whether hard and brittle, soft and tough, flexible, etc. Theoretically, it should seem possible to control the degree of hardness that results from heat treating steel, by regulating the rate of cooling through its critical temperatures. If, for example, we wanted a relatively soft and tough piece of steel we should simply have to cool it less rapidly than if we wanted a harder and stronger piece. Actually, however, it is very difficult to regulate the rate of cooling with sufficient precision so as to achieve the desired degree of hardness. In practice, therefore, steel is cooled at the fastest possi ble rate during hardening or heat treatment, and any undesired amount of hardness and brittleness is then removed later from the fully hardened piece by tempering. 89 a process of reheating steel to a temperature below the lower critical temperature. The hardness of steel is so closely related to its other properties, that if we achieve the correct degree of hardness in a piece after heat treatment and tempering, we can rely on its having the desired other properties. The unnatural needle-like formations of trapped carbide particles in hardened steel generate structural stresses, thereby exerting an internal force toward reforming into a more natural structure. At ordinary room temperature, however, modification of this unnatural structure is impossible. But as the fully hardened piece of steel is reheated, some of the trapped carbide spines do reform into spheres. This reforming starts as low as 212° F. As each higher temperature below the critical is reached, additional spines break down and reform into spheres, thus making the metal softer and tougher (less brittle). The highest temperature to which the hardened piece of steel is subjected during the reheating operation determines its final degree of hardness and brittleness (or softness and toughness), and is the important factor in tempering. 90 A tool such as a file, for example, is reheated to 212° F. This modifies some needles, thereby removing some of the brittleness but retaining practically all of the hardness. Cutting tools and wearing parts are tempered at about 400° F. This removes most brittleness and, of necessity, a little hardness. Battering tools are reheated to about 500° F.; still more needles are removed resulting in a loss of hardness, but more important, the tools are tougher and less apt to break under a blow. Springs are tempered at about 750° F. to obtain the best balance between hardness, toughness and flexibility. Parts reheated to 900°-1000° F. lose additional hardness but gain in toughness (or the ability to withstand a blow by bending before breaking). Each higher tempering temperature modifies an additional portion of the spiny structure. If a part should be overheated for any reason (thereby becoming too soft), it must be rehardened (i.e., heated above its critical temperatures and then cooled rapidly) and then tempered to the proper temperature. the criterion test 91 92 DIRECTIONS The questions on the following pages test your knowledge of the material that you studied recently. These questions are all of the multiple-choice type. For each question choose the lettered alternative that is most appropriate. If two or more answers seem appropriate, choose the one that seems most correct to you. Only one answer should be chosen for each question. Answer all questions even if you do not feel completely certain of your answer in a particular case. When you have decided which of the five lettered answers is correct for each question, blacken the cor responding space on the answer sheet with pencil or pen. Make sure that the number of each question you answer on the answer sheet corresponds to the same numbered question on the question sheet. You can avoid errors by answering each question as you come to it. Do not skip around from one question to another. 93 Be sure to place your name, age, sex, the date, and the Instructor's name in the appropriate places on the answer sheet. PLEASE MAKE NO MARKS ON THE QUESTION BOOKLET 94 THE PROPERTIES OF PLAIN CARBON STEEL QUESTION BOOKLET 1. The primary purpose of tempering steel is to reduce: (a) hardness (b) brittleness (c) wear-resistance (d) toughness (e) softness 2. An alloy is a substance composed of two or more elements: (a) which has metallic properties (b) which has at least one metal constituent (c) which do not interact chemically (d) "a" and "b" (e) "b" and "c" 3. The most reliable method of making the first of two identical pieces of steel harder than the second is to: (a) cool the first piece more slowly during heat treatment (b) cool the first piece more rapidly during heat treatment (c) heat the first piece to a higher temperature during heat treatment (d) temper the first piece at a higher temperature (e) temper the first piece at a lower temperature 4. In 0.60% carbon steel: (a) all of the iron grains are saturated with carbide (b) one-quarter of the iron grains are saturated with carbide (c) one-half of the iron grains are saturated with carbide (d) three-quarters of the iron grains are saturated with carbide (e) carbide forms in a she11-like layer around the grains of iron 95 5. A kitchen knife made of which of the following would remain sharp the longest? (a) .20% carbon steel (b) .40% carbon steel (c) .80% carbon steel (d) .95% carbon steel (e) 1.5% carbon steel 6. To be able to get maximum hardness in steel, it must contain: (a) at least 0.10% carbon (b) at least 0.40% carbon (c) at least 0.80% carbon (d) not over 1.5% carbon (e) not over 2.0% carbon 7. Which of the following events do not occur as steel is transformed from a mixture to a solution? Ca) the carbide particles become more highly dispersed (b) the metal becomes a liquid (c) the carbide particles become smaller (d) the grain structure varies with changes in temperature (e) the carbide particles acquire greater freedom to reform 8. By knowing the hardness of a piece of steel we do not know: (a) its toughness (b) its tensile strength (c) its corrosion resistance (d) its ability to withstand impact (e) its ability to withstand bending without breaking 9. When any alloy is examined under a powerful microscope, it can be demonstrated that: (a) it has a uniform internal structure throughout the piece (b) all grains have the same general appearance (c) all grains have the same size and general appearance (d) its internal components are not distinguishable from each other (e) "b* and "d" 96 10. Cooling a piece of steel rapidly from the tempering temperature will: (a) completely reharden the piece (b) partially reharden the piece depending on the tempering temperature (c) partially reharden the piece depending on the carbon content (d) partially reharden the piece depending on both tempering temperature and carbon content (e) have no effect whatsoever 11. A steel part with a tough center and a hard, wear- resistant surface (such as an axle) could be produced by: (a) hardening a high carbon steel part and then reheating only the surface (b) hardening a low carbon steel part and then reheating only the surface (c) hardening and tempering a low carbon steel in a carbon atmosphere (d) hardening and tempering a high carbon steel in an ordinary air atmosphere (e) hardening and tempering a low carbon steel in an ordinary air atmosphere 12. Which of the following statements is not true? (a) the carbide in 0.60% carbon steel starts to go into solution at the same temperature as the carbide in 0.40% carbon steel (b) the carbide in 0.60% carbon steel is all in solution at a lower temperature than the carbide in 0.40% carbon steel (c) the carbide in 1.5% carbon steel is all in solution at a lower temperature than the carbide in 0.80% carbon steel (d) the carbide in 1.5% carbon steel begins to go into solution at the same temperature as the carbide in 0.80% carbon steel (e) the carbide in 0.60% carbon steel begins to go into solution at the same temperature as the carbide in 0.80% carbon steel 97 13. Which tempering temperature is best for battering tools? (a) 300° F. (b) 400° F. (c) 500° F. (d) 750° F. (e) 950° F. 14. If a broken spring has been repaired by welding (joining the two pieces by remolting the metal at the break)t (a) the heated section must be cooled slowly (b) the heated section must be cooled rapidly (c) the entire piece must be retempered (d) the entire piece must be rehardened and re tempered (e) the entire piece must be retempered and cooled rapidly 15. Steel is an alloy of iron: (a) which contains less than 2% carbon (b) which always contains one or more alloying elements in addition to carbon (c) which may contain one or more alloying elements in addition to carbon (d) "a" and "b" (e) "a" and "c" 16. To make a steel maximally hard its temperature at the time of cooling must be: (a) above the upper critical (b) below the upper critical (c) at the melting point (d) below the lower critical (e) between the upper and lower critical 17. Springs are tempered at: (a) 300° F. (b) 400° F. (c) 550° F. (d) 750• F. (e) 920° F. 98 18. The carbide in steel begins to go into solution: (a) at 212® F. (b) at 500® F. (c) at 1000® F. <d) at 1350® F. (e) at none of the above 19. Steel with a carbon content over 0.80% is used where it is important to have: (a) extra hardness (b) increased flexibility (c) high corrosion resistance (d) great toughness (e) high wear resistance 20. The upper critical temperature of steel: (a) is the temperature above which steel melts (b) is the temperature at which all of the carbide in steel is in solution (c) is the temperature at which the carbide in steel begins to go into solution (d) is the temperature above which steel must be heated for tempering to take place (e) is the temperature below which steel solidifies 21. When a piece of high carbon steel is cooled rapidly from a solid solution, the piece will be: (a) soft (b) hard (c) soft and tough (d) hard and brittle (e) brittle 22. The most important consideration in choosing the tempering temperature of a finished steel part is: (a) its desired mechanical properties (b) the rate at which it was cooled (c) the maximum temperature during heat treatment (d) the carbon content of the part (e) the internal grain structure of the part 99 23. 24. 25. 26. 27. Which of the following alloys may be heat treated? (a) iron-chromium (b) iron-carbon-tungsten (c) copper-zinc (d) iron-nicke1-chromium (e) copper-tin Which of the following statements is not true? (a) slowly cooled 1.5% carbon steel is harder theui slowly cooled 1.0% carbon steel (b) slowly cooled 0.75% carbon steel is harder than slowly cooled 0.60% carbon steel (c) rapidly cooled 0.70% carbon steel is harder than rapidly cooled 0.50% carbon steel (d) rapidly cooled 0.80% carbon steel is harder than slowly cooled 0.80% carbon steel (e) rapidly cooled 1.5% carbon steel is harder them rapidly cooled 1.0% carbon steel When tempering a cutting tool that is to be driven with a hammer (e.g., a chisel), the following tempering temperature should be used: (a) 212° F. (b) 400° F. (c) 550° F. (d) 700• F. (e) 900° F. The effect of tempering steel first becomes noticeable at: (a) its upper critical temperature (b) its lower critical temperature (c) 212° F. (d) 900° F. (e) 1200® F. As the tempering temperature increases, steel becomes (a) tougher (b) harder (c) softer (d) tougher and harder (e) tougher and softer 100 28. The higher the carbon content of steel: (a) the lower the temperature at which all of the carbide is in solution (b) the higher the temperature at which all of the carbide is in solution (c) the higher the temperature at which the carbide starts going into solution (d) the lower the temperature at which the carbide starts going into solution (e) the higher its melting point 29. The most reliable way of having a piece of low carbon steel acquire a hard outer case during heat treatment is to: (a) use a particularly high maximum temperature during heat treatment (b) cool the outside of the piece more rapidly than the inside during heat treatment (c) heat treat and temper the piece in an atmosphere of ordinary air (d) heat treat and temper the piece in an atmosphere of carbon gases (e) harden the piece and then reheat only the surface 30. Which of the following statements about 0.80% carbon steel is not true? (a) its lower and upper critical temperatures are the same (b) it is more brittle than 0.40% carbon steel (c) its carbide starts going into solution at a lower temperature than the carbide of 0.40% carbon steel (d) it may be hardened at a lower temperature than 0.40% carbon steel (e) it is harder than 0.60% carbon steel 31. Steel is: (a) a compound of iron and carbon (b) a solution of iron and iron carbide (c) a solution or mixture of iron and iron carbide (d) a solution or mixture of iron and carbon (e) a solution of iron and carbon 101 32. Before a soft carbon steel can be hardened it must be changed: (a) from a mechanical mixture to a solid solution (b) from a liquid solution to a mechanical mixture (c) from a mechanical mixture to a solid solution and back to a mechanical mixture (d) from a solid solution to a mechanical mixture (e) from a solid solution to a mechanical mixture and back to a solid solution 33. Tempering should follow the hardening operation to increase: (a) hardness (b) toughness (c) brittleness (d) wear-resistance (e) corrosion resistance 34. Successful heat treatment largely depends upon: (a) the rate of cooling (b) the temperature from which the piece is cooled (c) the carbon content of the piece of steel prior to heat treatment (d) "a" and "fa te) -a" and "c" 35. A piece of metal may not be considered an alloy: (a) if its constituents form a compound (b) if it contains impurities (c) if its alloying constituent is found only in scattered pockets (d) if it contains inclusions of a metal or non- metal (e) if it contains impurities in the form of inclusions 36. The hardening operation, if properly performed, will: (a) produce any desired degree of hardness (b) result in equal hardness for all carbon steels (c) yield a steel of maximum strength and hardness (d) produce a degree of hardness relative to the carbon content (e) yield a hard and tough natural structure 102 37. In terms of its distinctive chemical-physical condition an alloy is defined as: (a) a solid solution <b) a solid solution or a liquid solution (c) a mixture (d) a solution or a mixture (e) a compound in solution 38. Maximally rapid cooling of steel from a solid solution results in: (a) fixing of carbide particles in a dispersed structure (b) fixing of carbide particles in a needle-like structure (c) fixing of carbide particles in the form of spheres within the iron grains (d) fixing of carbide particles in the form of layers within the iron grains (e) fixing of carbide particles in the form of layers around the iron grains 39. Alloys that may be hardened by heat treatment: (a) always have constituents entering into chemical combination (b) do not have a uniform internal structure through out a piece when viewed microscopically (c) always contain structurally distinct particles in addition to metallic grains (d) "a" and "c" (e) -a" and "b" 40. The most dependable way of regulating the ultimate hardness of a given piece of steel is to: (a) regulate the maximum temperature during heat treatment (b) regulate the rate of cooling through the critical temperatures (c) regulate maximum temperature during tempering (d) prevent a gain or loss of carbon content while these procedures are carried out (e) regulate the rate of cooling from the tempering temperature 103 41. During heat treatment the amount of carbon in a piece of steel may decrease: (a) if it is heated in an atmosphere of air (b) if its carbon content is originally more than 0.80% (c) if it is cooled too rapidly (d) if its carbon content is originally less than 0.80% (e) if the maximum temperature during heat treatment is excessive 42. If a cutting tool becomes heated and too soft during use: (a) it must be discarded (b) it must be retempered at a higher temperature (c) carbon must be added to it (d) it must be rehardened and retempered (e) it must be retempered at a lower temperature

Linked assets

University of Southern California Dissertations and Theses

Conceptually similar

PDF

Field-Independence And Typologies Of Delinquency

PDF

A Study Of The Comparability Of The Wisc And The Wais And The Factors Contributing To Their Differences

PDF

A Study Of Delinquency Among Urban Mexican-American Youth

PDF

Ego Diffusion In Women With Behavioral Disorders And The Integrating Effects Of Psychodrama In Identity Consolidation

PDF

Prediction Of Therapeutic And Intellectual Potential In Mentally Retardedchildren

PDF

Structure-Of-Intellect Factor Abilities And A Self-Concept Measure In Mathematics Relative To Performance In High School Modern Algebra

PDF

Proactive Effects In Meaningful Verbal Learning And Retention In Eighth Grade Students

PDF

The Appropriateness Of Field And Level Of Vocational Choice As Related Toself-Concepts, Intelligence, School Achievement, And Socioeconomic Status

PDF

A Study Of The Factorial Validity And Reliability Of The Individual Test Of Creativity

PDF

Effects Of Associative And Category Cuing On Recall Of Items From Exhaustive And Nonexhaustive Lists

PDF

A Study Exploring Two Different Approaches To Encounter-Groups: The Combination Of Verbal Encounter And Designed Nonverbal Activity Versus Emphasis Upon Verbal Activity Only

PDF

Effects Of Labeling As Emr On Teachers' Expectancies For Change In A Student'S Performance

PDF

Use Of College Students In A Social Therapy Program With Chronic Schizophrenics To Produce Changes In Mood And Social Responsiveness

PDF

The Conditioning Of A Discriminative Stimulus Measured As An Orienting Reaction In Profoundly Retarded Blind Children

PDF

A Cross-Cultural Study Of The Use Of Art Forms

PDF

An Investigation Of Leader And Member Helpfulness In Group Counseling

PDF

An Experimental Analysis Of The Relationship Between The Reliability Of Amultiple-Choice Examination And Various Test-Scoring Procedures

PDF

Personality Variables And Intellectual Abilities As Determinants Of Concept Learning

PDF

The Effects Of Pretraining In Auditory And Visual Discrimination On Texting In First Grade Boys

PDF

Effects Of Success And Failure On Impulsivity And Distractibility Of Three Types Of Educationally Handicapped Children

Asset Metadata

Creator Munford, Paul Rochester (author)

Core Title Advance Organizers And The Enchancement Of Meaningful Verbal Learning Andretention

Degree Doctor of Philosophy

Degree Program Education

Publisher University of Southern California (original), University of Southern California. Libraries (digital)

Tag education, educational psychology,OAI-PMH Harvest

Language English

Contributor Digitized by ProQuest (provenance)

Advisor Meyers, Charles Edward (committee chair), Lovell, Constance (committee member), Ofman, William V. (committee member)

Permanent Link (DOI) https://doi.org/10.25549/usctheses-c18-575018

Unique identifier UC11363286

Identifier 7211945.pdf (filename),usctheses-c18-575018 (legacy record id)

Legacy Identifier 7211945

Dmrecord 575018

Document Type Dissertation

Rights Munford, Paul Rochester

Type texts

Source University of Southern California (contributing entity), University of Southern California Dissertations and Theses (collection)

Access Conditions The author retains rights to his/her dissertation, thesis or other graduate work according to U.S. copyright law. Electronic access is being provided by the USC Libraries in agreement with the au...

Repository Name University of Southern California Digital Library

Repository Location USC Digital Library, University of Southern California, University Park Campus, Los Angeles, California 90089, USA