DOCSLIB.ORG

Understanding the Role of the Modality Principle in Multimedia Learning Environments Amy Marie Oberfoell Iowa State University

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Understanding the Role of the Modality Principle in Multimedia Learning Environments Amy Marie Oberfoell Iowa State University Iowa State University Capstones, Theses and Graduate Theses and Dissertations Dissertations 2015 Understanding the role of the modality principle in multimedia learning environments Amy Marie Oberfoell Iowa State University Follow this and additional works at: https://lib.dr.iastate.edu/etd Part of the Curriculum and Instruction Commons, and the Instructional Media Design Commons Recommended Citation Oberfoell, Amy Marie, "Understanding the role of the modality principle in multimedia learning environments" (2015). Graduate Theses and Dissertations. 14602. https://lib.dr.iastate.edu/etd/14602 This Thesis is brought to you for free and open access by the Iowa State University Capstones, Theses and Dissertations at Iowa State University Digital Repository. It has been accepted for inclusion in Graduate Theses and Dissertations by an authorized administrator of Iowa State University Digital Repository. For more information, please contact [email protected]. Understanding the role of the modality principle in multimedia learning environments by Amy Marie Oberfoell A thesis submitted to the graduate faculty in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE Major: Education (Curriculum and Technology Instruction) Program of Study Committee Ana-Paula Correia, Major Professor Denise Schmidt-Crawford Volker Hegelheimer Iowa State University Ames, Iowa 2015 Copyright © Amy Marie Oberfoell, 2015. All rights reserved ii TABLE OF CONTENTS LIST OF FIGURES………………………………………………………………………………iv LIST OF TABLES………………………………………………………………………………...v ACKNOWLEDGEMENTS……………………………………………………………………...vi ABSTRACT…………………………………………………………………………………….vii CHAPTER 1 INTRODUCTION .................................................................................................... 1 1.1 Purpose of the Study & Research Questions .................................................................... 6 1.2 Significance of the Study ................................................................................................. 9 CHAPTER 2 LITERATURE REVIEW ....................................................................................... 12 2.1 Instructional Design and the Instructional Designer ........................................................... 14 2.2 Modality Principle and Cognitive Load .............................................................................. 16 2.3 Increasing Working Memory Space .................................................................................... 18 2.4 A Closer Look at Cognitive Load ....................................................................................... 20 2.5 Multimedia Learning and the Modality Principle ............................................................... 25 2.6 The Redundancy Principle and Expertise Reversal ............................................................ 28 2.7 Diversification ..................................................................................................................... 29 2.8 Current Research on the Modality Principle ....................................................................... 30 CHAPTER 3 METHODOLOGY ................................................................................................. 40 3.1 Participants and Research Design ........................................................................................... 42 Materials ................................................................................................................................ 43 3.2 Procedure ........................................................................................................................ 48 3.3 Scoring the Items ............................................................................................................ 53 CHAPTER 4 DATA ANALYSIS & RESULTS .......................................................................... 56 iii 4.1 Pre-Survey Data Analysis .............................................................................................. 57 4.2 Overall Picture of Data Analyzed .................................................................................. 58 4.3 Reliability Analysis ........................................................................................................ 59 4.4 T-Tests ................................................................................................................................. 61 4.5 One-Way ANOVA Tests .................................................................................................... 63 CHAPTER 5 CONCLUSION AND DISCUSSIONS ................................................................. 71 5.1 Contributions of this Study ................................................................................................. 75 Implications ............................................................................................................................... 77 Limitations and Further Research ............................................................................................. 78 References ................................................................................................................................. 79 APPENDIX A POWERPOINTS USED IN STUDY ................................................................... 91 APPENDIX B PRE-SURVEY ..................................................................................................... 94 APPENDIX C RETENTION TEST QUESTION ........................................................................ 97 APPENDIX D TRANSFER TEST QUESTIONS ........................................................................ 98 APPENDIX E MATCHING TEST QUESTIONS ....................................................................... 99 APPENDIX F EXEMPT FORM IRB......................................................................................... 101 iv LIST OF FIGURES Figure 1.1 Cognitive Load Influences……………………………………………….…03 Figure 2.2 ADDIE Model………………………………………………………….…...15 Figure 2.6 Cognitive Theory of Multimedia Learning…………………………….…...27 Figure 2.9 Cognitive-Affective Theory of Learning with Media……………………...34 Figure 3.2 Sampling of Lightning PowerPoint Slides….………………………………46 Figure 4.1 Three Test Comparison……………….…………………………………….66 v LIST OF TABLES Table 1.1 Total and Online Enrollment in Degree-Granting Post-secondary Institutions……….10 Table 3.1 General USA University Grading Scale……………………………………………....53 Table 4.1 Data for Question Type, Number of Questions, and Number of Participants per group ………………………………………………………………………………………...59 Table 4.2 Results from Cronbach’s Alpha with AN Group……………………………………..60 Table 4.3 Results from Cronbach’s Alpha with AT Group……………………………………...60 Table 4.4 Results from Retention T-Test……………………………………………………..….62 Table 4.5 Results from Transfer T-Test……………………………………………………….....62 Table 4.6 Results from Matching T-Test………………………………………………………...63 Table 4.7 One-Way ANOVA Retention Scores………………………………………………....64 Table 4.8 One-Way ANOVA Transfer Scores………………………………………………..…65 Table 4.9 One-Way ANOVA Matching/Recall Scores……………………………………….....65 vi ACKNOWLEDGEMENTS I would like to begin by thanking my committee chair, Dr. Ana-Paula Correia, who helped me understand my role as a researcher, and my committee members Dr. Denise Schmidt- Crawford, and Dr. Volker Hegelheimer for their guidance and support. I would also like to thank Dr. Larysa Nadolny who collaborated with me in completing my study, and in providing sound ideas and process. I would also like to thank Dr. Richard Mayer for kindly sharing his original study materials and his willingness to respond to my questions, as well as the late Dr. Roxanna Moreno, whose research excited me and challenged me to look into the modality principle. I would also like to thank Dr. Catherine Stewart, a dear friend, who supported my additional questions and moments of frustration with gentle reminders that the barriers I saw were merely stepping stones on my journey. In addition, I would like to thank my wonderful children who were required to take on tasks that were often mine and were willing to pitch-in as needed giving me the ability to work full- time and go to school. In the end, however, my largest gratitude goes to my husband who had to take on so much more than one parent should, and he did so with kindness, strength and love. I hope I can be the same to all of you. My sincere thanks. vii ABSTRACT The modality principle was first addressed in 1989 by Mayer and Moreno. The modality principle asserts presenting words as speech, rather than on-screen text, is more effective for the learner. The modality principle states that learners are more successful with understanding information that uses narration than on-screen text because the on-screen text may produce a cognitive overload if it is accompanied by other visual elements. This overload may occur due to the learner needing to give attention to the visual graphic/image as well as provide visual attention to the on-screen text. However, if the on-screen text is narrated, the learner will be able to process this information with the auditory channel and thereby, not taxing the visual channel. Over the next fifteen years, additional studies were completed addressing the modality principle. Many of the studies provided additional data and support for the modality principle in multimedia learning environments. However, some studies began to show the modality principle’s impact had certain parameters and was impacting different
Load more

Recommended publications
  • Understanding the Role of the Modality Principle in Multimedia Learning Environments Amy Marie Oberfoell Iowa State University
    View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by Digital Repository @ Iowa State University Iowa State University Capstones, Theses and Graduate Theses and Dissertations Dissertations 2015 Understanding the role of the modality principle in multimedia learning environments Amy Marie Oberfoell Iowa State University Follow this and additional works at: https://lib.dr.iastate.edu/etd Part of the Curriculum and Instruction Commons, and the Instructional Media Design Commons Recommended Citation Oberfoell, Amy Marie, "Understanding the role of the modality principle in multimedia learning environments" (2015). Graduate Theses and Dissertations. 14602. https://lib.dr.iastate.edu/etd/14602 This Thesis is brought to you for free and open access by the Iowa State University Capstones, Theses and Dissertations at Iowa State University Digital Repository. It has been accepted for inclusion in Graduate Theses and Dissertations by an authorized administrator of Iowa State University Digital Repository. For more information, please contact [email protected]. Understanding the role of the modality principle in multimedia learning environments by Amy Marie Oberfoell A thesis submitted to the graduate faculty in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE Major: Education (Curriculum and Technology Instruction) Program of Study Committee Ana-Paula Correia, Major Professor Denise Schmidt-Crawford Volker Hegelheimer Iowa State University Ames, Iowa 2015 Copyright © Amy Marie Oberfoell,
    [Show full text]
  • Abstract the EFFECTS of PRESENTATION MODALITY ON
    Abstract THE EFFECTS OF PRESENTATION MODALITY ON LEARNING AND MEMORY PERFORMANCE IN CHILDREN WITH SPECIFIC LEARNING DISABILITIES IN THE AREA OF LANGUAGE By Marijo F. O’Connell This study investigated the learning and memory patterns in low-income, African- American children ages 9-13 with specific learning disabilities in the area of language (SLD/SLI) as compared to typically developing peers. All subjects (n=34) were administered the California Verbal Learning Test for Children (CVLT-C) and the experimental tasks. The experimental tasks measured supralist free recall under three presentation modalities; auditory, visual and simultaneous presentation of auditory and visual. Results indicate SLD/SLI children show significantly slower rates of learning than controls. Additionally, the visual presentation modality, with or without auditory information, demonstrates significantly better learning rates than the auditory modality alone. The results support the hypotheses stating that SLD/SLI children learn verbal information at a slower rate than typical children and the superiority of the visual presentation modality for verbal learning and memory. Effect of Presentation Modality on Learning and Memory Performance in Children with Specific Learning Disabilities in the Area of Language A Thesis Submitted to Miami University in partial fulfillment of the requirements for the degree of Master of Arts Department of Speech Pathology and Audiology by Marijo F. O’Connell Miami University Oxford, Ohio 2005 Advisor: ______________________________
    [Show full text]
  • The Split-Attention Principle in Multimedia Learning
    CHAPTER 8 The Split-Attention Principle in Multimedia Learning Paul Ayres John Sweller University of New South Wales Abstract Definition of Split-Attention The split-attention principle states that Instructional split-attention occurs when when designing instruction, including mul­ learners are required to split their atten­ timedia instruction, it is important to tion between and mentally integrate sev­ avoid formats that require learners to split eral sources of physically or temporally dis­ their attention between, and mentally in­ tegrate, multiple sources of information. parate information, where each source of Instead, materials should be formatted so information is essential for understanding that disparate sources of information are the material. Cognitive load is increased by physically and temporally integrated thus the need to mentally integrate the multi­ obviating the need for learners to en­ ple sources of information. This increase in gage in mental integration. By eliminat­ extraneous cognitive load (see chapter 2) is ing the need to mentally integrate multiple likely to have a negative impact on learn­ sources of information, extraneous work­ ing compared to conditions where the infor­ ing memory load is reduced, freeing re­ mation has been restructured to eliminate sources for learning. This chapter provides the need to split attention. Restructuring the theoretical rationale, based on cog­ occurs by physically or temporally inte­ nitive load theory, for the split-attention principle, describes the major experiments grating disparate sources of information to that establish the validity of the princi­ eliminate the need for mental integration. ple, and indicates the instructional de­ The split-attention effect occurs when learn­ sign implications when dealing with multi­ ers studying integrated information outper­ media materials.
    [Show full text]
  • Modality Effects and the Structure of Short-Term Verbal Memory
    Memory & Cognition 1989, 17 (4), 398-422 Modality effects and the structure of short-term verbal memory CATHERINE G. PENNEY Memorial University of Newfoundland, St. John's, Newfoundland, Canada The effects of auditory and visual presentation upon short-term retention of verbal stimuli are reviewed, and a model of the structure of short-term memory is presented. The main assumption ofthe model is that verbal information presented to the auditory and visual modalities is processed in separate streams that have different properties and capabilities. Auditory items are automat­ ically encoded in both the A (acoustic) code, which, in the absence of subsequent input, can be maintained for some time without deliberate allocation of attention, and a P (phonological) code. Visual items are retained in both the P code and a visual code. Within the auditory stream, suc­ cessive items are strongly associated; in contrast, in the visual modality, it is simultaneously presented items that are strongly associated. These assumptions about the structure of short­ term verbal memory are shown to account for many ofthe observed effects ofpresentation modality. Penney (1975) reviewed the literature on the effects of the distraction did not require a long period of vocaliza­ presentation modality on short-term retention of verbal tion. Overt vocalization of a visually presented list by the material and concluded that there were separate stores for subject produced much the same effect as did auditory auditorily and visually presented information. To empha­ presentation on the recency part of the serial position size the idea that active processing underlies retention in curve, but subject vocalization tended to reduce recall in short-term memory, and to discourage the conceptuali­ the nonrecency part of the serial position curve.
    [Show full text]
  • An Examination of the Effects of Mathematics Anxiety
    AN EXAMINATION OF THE EFFECTS OF MATHEMATICS ANXIETY, MODALITY, AND LEARNER-CONTROL ON TEACHER CANDIDATES IN MULTIMEDIA LEARNING ENVIRONMENTS by Elena Elizabeth Ward A thesis submitted to the Faculty of Education in conformity with the requirements for the degree Master of Education Queen’s University Kingston, Ontario, Canada September, 2008 Copyright © Elena Elizabeth Ward, 2008 ISBN: 978-0-494-42743-9 Abstract This study examined mathematics anxiety among elementary teacher candidates, and to what extent it interacted with the modality principle under various degrees of learner-control. The experiment involved a sample of 186 elementary teacher candidates learning from eight versions of a computer program on division with fractions. The eight versions varied in modality of presentation (diagrams with narration, or diagrams with written text), control of pacing (pacing was controlled by either the learner or the system), and control of sequence (sequence was controlled by either the learner or the system). A pre-test, post-test, demographic questionnaire, subjective measure of mental effort, and the Abbreviated Math Anxiety Survey were also administered. This study revealed that mathematics anxiety was significantly positively correlated with mental effort, and significantly negatively correlated with engagement, pre-test and post-test scores. Additionally, a modality x pacing interaction was observed for both high prior knowledge and low mathematics-anxious students. Under system-pacing, the modality effect was observed, and these students achieved higher far transfer scores when learning from the diagrams and narration modality condition. However, under learner-pacing, the modality effect reversed, and high prior knowledge and low mathematics-anxious students performed better on far transfer scores when learning from the diagrams and written text modality condition.
    [Show full text]
  • Running Head: MODALITY EFFECTS in FREE RECALL 1
    Running head: MODALITY EFFECTS IN FREE RECALL 1 Modality effects in free recall: A retrieved-context account Pazdera, J. K. and Kahana, M. J. University of Pennsylvania Author Note Support for this work was provided by the National Institutes of Health (MH55687). The authors would like thank Rivka Cohen for assistance in designing and programming our simulations, Tung Phan for helping to design our intrusion analysis for Experiment 1, as well as Bob Greene, Alice Healy, and Geoff Ward for providing insightful feedback on an earlier draft of this manuscript. Correspondence concerning this article should be addressed to Michael J. Kahana. E-mail: [email protected] MODALITY EFFECTS IN FREE RECALL 2 Abstract The modality effect refers to the robust finding that memory performance differs for items presented aurally, as compared with visually. Whereas auditory presentation leads to stronger recency performance in immediate recall, visual presentation often produces better primacy performance. To investigate these differences, we conducted two large-scale immediate free recall experiments via Amazon Mechanical Turk. In both experiments, participants studied visual and auditory word lists of varying lengths and rates of presentation. We observed a recency advantage and primacy disadvantage during auditory trials, relative to visual trials, reflecting common modality and inverse modality effects in free recall. Participants were more likely to initiate recall from recency items on auditory trials than on visual trials, though the modality effect persisted regardless of recall start location. Meanwhile, an analysis of intrusion errors revealed that participants were more likely to erroneously recall words from one list prior on visual trials than they were on auditory trials.
    [Show full text]
  • Modality Effects in the Coding Reproduction of Rhythms
    Memory & Cognition 1989. 17 (4), 373-383 Modality effects in the coding and reproduction of rhythms ARTHUR M. GLENBERG, STUART MANN, LISA ALTMAN, TIM FORMAN, and SEAN PROCISE University of Wisconsin, Madison, Wisconsin The temporal coding assumption is that time of presentation is coded more accurately for audi­ tory events than for visual events. This assumption has been used to explain the modality effect, in which recall of recent auditory events is superior to recall of recent visual events. We tested the temporal coding assumption by examining the coding and reproduction of quintessentially temporal stimuli-rhythms. The rhythms were produced by sequences of short and long auditory stimuli or short and long visual stimuli; in either case, the task was to reproduce the temporal sequence. The results from four experiments demonstrated reproduction of auditory rhythms superior to that of visual rhythms. We conclude that speech-based explanations of modality ef­ fects cannot accommodate these findings, whereas the findings are consistent with explanations based on the temporal coding assumption. In classic information processing models of memory Glavanov, and Murdock (1981) presented stimuli in dif­ (e.g., Atkinson & Shiffrin, 1968), the input modality of ferent spatial locations. Auditory stimuli were recalled bet­ information plays little role after the information is coded ter than were visual stimuli when recall was by temporal in short-term store. In fact, early work on the modality position, but this difference was eliminated when recall effect (e.g., Crowder & Morton, 1969) seemed to con­ was by spatial location. Glenberg and Swanson (1986) firm this limited role: Auditory information is recalled manipulated the duration of the intervals separating suc­ better than is visual information, but only at the end of cessive to-be-remembered items on a list.
    [Show full text]
  • On the Auditory Modality Superiority Effect in Serial Recall: Separating Input and Output Factors
    Journal of Experimental Psychology: Copyright 2004 by the American Psychological Association Learning, Memory, and Cognition 0278-7393/04/$12.00 DOI: 10.1037/0278-7393.30.3.639 2004, Vol. 30, No. 3, 639–644 On the Auditory Modality Superiority Effect in Serial Recall: Separating Input and Output Factors Nelson Cowan and J. Scott Saults Gordon D. A. Brown University of Missouri—Columbia University of Warwick The modality effect in immediate recall refers to superior recall of the last few items within lists presented in spoken as opposed to printed form. The locus of this well-known effect has been unclear. N. Cowan, J. S. Saults, E. M. Elliott, and M. Moreno (2002) introduced a new method to distinguish between the effects of input serial position, output serial position, and the number of items yet to be recalled and found that large modality effects occurred only in conditions in which delay and interference at output (from items already recalled) was high. The authors replicated that finding, even when the response period included output interference acoustically similar to the spoken stimuli to be recalled. However, the authors found that output delay and interference act only by lowering the level of performance to a more sensitive range. The modality effect thus originates during encoding of the list to be recalled, not during output. In research on human cognition, the overwhelming majority of nine-item digit lists were presented and recall began at Serial experiments have involved the presentation of stimuli to the eyes, Position 1, 4, or 7. On some trials, the participant was to stop after the ears, or both.
    [Show full text]
  • Effects of Presentation Format on Memory for Order
    Effects of Presentation Format on Memory for Order Margaret J. Peterson ([email protected]) Erik M. Altmann ([email protected]) Human Factors & Applied Cognition George Mason University Fairfax, VA 22030 Abstract ual presentation, especially for the last items in a list. This pronounced recency effect for auditory modality is similar to Memory for order is important in everyday settings, for the effect seen in item memory. Similarly, Neath (1997) example in eyewitness testimony about who started a con- showed that set-size, presentation modality, and word con- flict. Although current theories claim that memory for or- creteness all have similar effects on order memory as they do der is different from memory for the to-be-remembered items themselves, many of the same manipulations that af- on item recognition and recall. fect item memory also affect order memory. One manipula- If order memory is similar to item memory, one might tion that has shown effects in item memory, but that has expect it to differ across other manipulations that produce not been tested in order memory, is presentation format. differences in item memory. One such difference is between The hypothesis tested here is that order memory will be pictures and text. In recall and recognition tasks, pictorial better for actions described as pictures than for actions de- presentation of items produces higher accuracy than verbal scribed by text. The hypothesis is not supported by a main presentation (Baggett, 1979; Snodgrass, Wassner, Finkel- effect. However, presentation format does interact with se- stein, & Goldberg, 1974). Dual-coding theory provides one rial position, suggesting that format effects are analogous possible explanation for these results.
    [Show full text]
  • Word Length and the Structure of Short-Term Memory
    JOURNAL OF VERBAL LEARNING AND VERBAL BEHAVIOR 14, 575-589 (1975) Word Length and the Structure of Short-Term Memory ALAN D. BADDELEY Medical Research Council, Applied Psychology Unit AND NElL THOMSON AND MARY BUCHANAN University of Stifling, Scotland A number of experiments explored the hypothesis that immediate memory span is not constant, but varies with the length of the words to be recalled. Results showed: (1) Memory span is inversely related to word length across a wide range of materials; (2) When number of syllables and number of phonemes are held constant, words of short temporal duration are better recalled than words of long duration; (3) Span could be predicted on the basis of the number of words which the subject can read in approximately 2 sec; (4) When articulation is suppressed by requiring the subject to articulate an irrelevant sound, the word length effect disappears with visual presentation, but remains when presentation is auditory. The results are interpreted in terms of a phonemically-based store of limited temporal capacity, which may function as an output buffer for speech production, and as a supplement to a more central working memory system. Miller (1956) has suggested that the items, where items are defined experimental capacity of short-term memory is constant units. Words represent one commonly ac- when measured in terms of number of cepted type of item, and in this case, the chunks, a chunk being a subjectively meaning- chunking hypothesis would predict that the ful unit. Because of the subjective definition capacity of short-term memory, as measured of a chunk, this hypothesis is essentially in words, should be constant regardless of the irrefutable unless an independent measure of size or duration of the words used.
    [Show full text]
  • The Modality Effect Tested in Children in a User-Paced Multimedia
    Original article doi: 10.1111/j.1365-2729.2009.00335.x The modality effect tested in children in a user-paced multimedia environmentjcal_335 132..142 M.J. Witteman*† & E. Segers* *Behavioural Science Institute, Radboud University Nijmegen, Nijmegen, The Netherlands †Max Planck Institute for Psycholinguistics, Nijmegen, The Netherlands Abstract The modality learning effect proposes that learning is enhanced when information is pre- sented in both the visual and the auditory domains (e.g. pictures and spoken information) compared with presenting information solely in the visual channel (e.g. pictures and written text). Most of the evidence for this effect comes from adults in a laboratory setting. Therefore, we tested the modality effect with 80 children in the highest grade of elementary school in a naturalistic setting. In a between-subjects design, the children either saw representational pictures with speech or representational pictures with text. Retention and transfer knowledge was tested at three moments: immediately after the intervention, one day after and after one week. The present study did not find any evidence for a modality effect in children when the lesson was learner-paced. Instead, we found a reversed modality effect directly after the intervention for retention. A reversed modality effect was also found for the transfer questions one day later. This effect was robust, even when controlling for individual differences. Keywords long term effects, individual differences, modality effect, multimedia learning, primary school, user-paced. adults, often on college students. It is not clear, however, Introduction whether these results can be generalized to children. The information age is in full swing, and digital media The goal of the present study is to test the modality influence more and more of our daily lives.
    [Show full text]
  • Term Memory in Computer-Environment Learning Tasks
    Graduate Theses, Dissertations, and Problem Reports 2009 Effects of color and animation on visual short -term memory in computer-environment learning tasks Marc Debiase West Virginia University Follow this and additional works at: https://researchrepository.wvu.edu/etd Recommended Citation Debiase, Marc, "Effects of color and animation on visual short -term memory in computer-environment learning tasks" (2009). Graduate Theses, Dissertations, and Problem Reports. 2895. https://researchrepository.wvu.edu/etd/2895 This Dissertation is protected by copyright and/or related rights. It has been brought to you by the The Research Repository @ WVU with permission from the rights-holder(s). You are free to use this Dissertation in any way that is permitted by the copyright and related rights legislation that applies to your use. For other uses you must obtain permission from the rights-holder(s) directly, unless additional rights are indicated by a Creative Commons license in the record and/ or on the work itself. This Dissertation has been accepted for inclusion in WVU Graduate Theses, Dissertations, and Problem Reports collection by an authorized administrator of The Research Repository @ WVU. For more information, please contact [email protected]. i Effects of Color and Animation on Visual Short-Term Memory in Computer-Environment Learning Tasks Marc Debiase Dissertation submitted to the College of Human Resources and Education at West Virginia University in partial fulfillment of the requirements for the degree of Doctor of Education in Instructional Design and Technology Terence C. Ahern, Ph.D. Chair Daniel Hursh, Ph.D. Chair Richard T. Walls, Ph.D. R. Neal Shambaugh, Ph.D.
    [Show full text]