Computer Animation in an Instructional Environment 1996 1997 Library Information Science Research

LISR l&3-23 (1996)

Computer Animation iu an Instructional Environment

Andrew Large Graduate School of Library & Information Studies, McGill University

Montreal, Quebec, Canada

This article reviews the effectiveness of animation in enhancing textual information for instructional purposes. The theoretical basis for visual effectiveness is controversial and rests on competing theories such as dual coding, single coding, and mental models. The role of pictures in prose is briefly reviewed to identify the factors which determine the effectiveness of illus- trative material in printed books, and the visual effects of television as an inst~ctional medium are summarized. Research on the effectiveness of educational technologies is prone to a number of methodological problems, which are outlined. Design criteria for multimedia instructional products are summarized.

COMPUTJJRS AND ANIMATION

Animation can be included in a variety of computerized instructional environments. Initially, it tended to be used in computer-based inst~ction programs using a medium such as videodisc to store sequences of animation alongside text and stillimages. More recently, a wide range of products which can serve in an ins~ctional environment has been launched as interactive multimedia products, normally using CD-ROM as the storage medium. Multimedia applications share two main characteristics: first, they combine information in several media-typically text, still images, moving images (animation and video) and sound; and second, they are interactive, permitting users to call up information in any one of these media as required and to navigate very flexibly through the multimedia database, often using hypertext structures.

The virtues of images for educational purposes have been extolled by many authorities. Thomas Edison, for example, predicted in 1921 that in ten years textbooks as the principle method of teaching will be as obsolete as the horse and carriage are now. He added: I believe that . . . visual education-the imparting of exact information through the motion picture camera-will be a matter of course in all of our schools. Seventy-five years later his prediction now seems closer to realization. Large numbers of multimedia products inco~rating animation can be used for instruction. Many of these products are specifically designed as instructional tools to be used in an educational or training context, where the mult~edia environment is intended to facilitate specific learning objectives. Multimedia works such

Direct correspondence to Andrew Large, Graduate School of Library & Information Studies, McGill University, 3459 McTavish St., Montreal H3A 2571 Quebec, Canada .

3

4 Large

as encyclopedias and atlases are widely available in schools, and Fryer (1994) reports that 45% of the larger companies in a 1993 survey of Fortune 1000 companies used multimedia for in-house training purposes.

Multimedia applications typically have been greeted with enthusiasm by product reviewers, teachers, and trainers. As Bennet (1994, p. 84) comments, Evalu- ations tend toward the uncritical, particularly in that they pay excessive attention to gizmos. In a review of two IBM products (Columbus: Encounter, Discovery and Beyond; and Illuminated Books and Manuscripts), for example, Flanders (1992, p. 32) stated that the new educational programs provide students with a rich, comprehensive knowledge system, giving them the ability to experience a vast number of learning activities, in essence, to engage in exploration and discovery. Howson and Davis (1992, p. 12), one a teacher and the other a videodisc publisher, remarked: Everyone, especially educators, knows that learning takes place through the senses. The more senses touched, the greater the opportunity of concept development by students. The result is comprehension. Prickett (1992, p. 56) is equally enthusiastic: Multimedia provides multi-dimensional learning experiences to help students go beyond the walls of the classroom, taking their learning in multiple directions rather than following a linear path.

Despite such widespread enthusiasm for the learning potential of multimedia, critics have cautioned that technology is but a means to an end rather than an end in itself in which the more dazzling the technological display the more effective is deemed the product. As Rieber (1989b) says, increased hardware capabilities cou- pled with increasingly literate and sophisticated educational consumers demanding leading edge design has tended to spur greater amounts of glitter in software without serious regard to its instructional effectiveness.

A growing body of research questions whether or not images enhance text to facilitate learning, and if they do, does this happen only under certain conditions? The purpose of this article is to review the evidence for animation as an enhancement to text in a multimedia environment. Animation can be defined as a series of rapidly changing computer screen displays that present the illusion of movement (Rieber & Hannafin, 1988). It is not real motion, but merely a representation of motion. When individual static images are shown collectively at a minimum of 15 frames per second the motion is perceived as being smooth and continuous (Rieber, 1991). Attention is centered here on animation for several reasons. The incorpora- tion of moving images is the most novel aspect of many multimedia products, and animation is more common than full-motion video (largely because it is much less demanding on hardware storage and retrieval capabilities). Still images are more analogous to illustrations in printed books (see below), and consequently less singu- larly linked to the concept of multimedia. Researchers have devoted most attention to animation. Interesting use can be made of sound in multimedia-the human voice, music and sound effects-but as yet relatively little research has examined it. Most multimedia products place heavy reliance on text to convey information, and typically other media, including animation, supplement rather than replace text. For this reason, research has often sought to compare the instructional effect of information delivered in text form only compared with the effect of supplementing that text with animation sequences.

Computer Animation in an lnstruct~onal Environment 5

THE THEORETICAL BASIS FOR VISUAL EFFECTIVENESS

According to Bartletts Familiar Quofatiuns (1980), a Chinese proverb is responsible for the often quoted saying that a picture is worth more than ten thousand words. As we shall see, the assertion that pictures can convey information more effectively than text requires considerable qualification. Pictures are not uniformly effective in all situations, and not all types of pictures are equally effective. In general, though, memory is greater for pictures than words. Pictures, whether still or moving, can facilitate storage and retrieval of text content under certain conditions. Why should this be so? It must be conceded at the outset, as a leading autho~ty on picture research has confessed, that we do not know very much about why and how pictures facilitate learning from text (Levin in Mandl & Levin, 1989, p. 83).

During information decoding by the brain, texts and pictures appear to be handled differently, although reading and viewing certainly share many similarities. Both involve special eye movements and pattern recognition that can be traced to the development of writing from pictorial representations (Molitor, Ballstaedt, & Mandl, 1989). The higher stages of processing remain elusive and controversial. For example, there is no consensus on whether text and pictures are processed through different memory systems and different formats, or whether there is one memory system in which all knowledge is stored in one format regardless of its original representation as text or picture. Simpson (1994) discusses neurological evidence for the effect of media on learning and memory, but concedes that many questions remain unanswered. There is, however, general theoretical support for the importance of the visualization of knowledge in working memory (Gagne, 1985). The ability to visualize may be innate, but adults are better at constructing their own mental images than children. Older students, therefore, have iess need of external visuals to create their own mental images (Pressley, 1977).

The argument that text and pictures are handled differently by the brain has most forcefully been propounded by Paivio (1971, 1986) in his dual processing theory. He posits the existence of two different memory stores, one visual and one verbal, and concludes that information encoded in both stores will be better remembered than information encoded in one store only. Two explanations are given for this result: if something is coded in both visual and verbal forms it is more likely to be remembered than if it is only coded in one form, and a picture may be coded both visually and verbally (twice), whereas words are more likely only to be coded as words and not as pictures (hence, the well-known mnemonic device of visualizing words that are to be committed to memory). This dual coding theory has not met universal acclaim. A rival theory, most radically propounded by Pylyshyn (1981), presents the case for single coding and asserts that all knowledge ultimately is propositional.

If the dual coding theory is correct, then text and pictures are subject to different processes, and it is probable that the presentation form plays an essential role in learning. If, on the other hand, the single-code theory is correct, then the mode of presentation should play a lesser role in learning as it will only affect peripheral rather than central processing. A mid-position between dual and single coding is occupied by the theory of mental models-representations of a limited area of reality by concrete experiences which can be conveyed by both pictures and text,

6 Large

Pictures assist in the construction and management of mental models in memory. For Glenberg and Langston (1992), a picture can assist in the construction of a mental model because the structure of the picture (the relations between the parts) is often identical to the required structure of a mental model. At any rate, as Rieber (1994) says, there is considerable evidence that in general, and for whatever reason, memory is greater for pictures than for words.

PICTURES IN PROSE

M~timedia may be a new technology, but the addition of images to text in order to facilitate learning has a much longer history. Alesandrini (1982) defines a picture as any relevant, two-dimensional representation in which the stimulus array contains at least one element that is not alphabetic, numeric, or arithmetic. Pictures within texts have two characteristics: they depict some elements from the text; and they provide additional information to that contained in the text (Peeck, 1989). Most pictures display, to a greater or lesser extent, both these characteristics.

Writing systems developed from simple sketches, and the route from pictograms to phonetic alphabets passed through several intermediary stages such as Egyptian hieroglyphics where pictures and texts coincided (Molitor, Ballstaedt, & Mandl, 1989). Illustration is an ancient human skill to which cave paintings at least 20,000 years old testify. The Egyptian Book of the Dead (1300 B.C.) as well as the earliest versions of the Aeneid and Iliad contain illustrations. The addition of illustrations to text became more common with the invention of wood engraving at the end of the 14th century. During the Renaissance pictures were used alongside text in the emerging sciences and the note books of Leonardo da Vinci, for example, are rich in drawings. Illustrations have long held a special place in childrens books. They date back at least to Ulrich Boners Der EdeLstein, which appeared in 1461, and the first illustrated childrens book to be printed with moveable type was Caxtons Aesop in 1484 (Pressley & Miller, 1987). The Czech educator, Johann Comenius, was the first to give an explicit pedagogic goal to pictures in a textbook, and his Orbis sensualium pictus (1658) combined text with illustrations which were explicitly intended as mnemonic aids for students learning Latin (Large, 1985).

Pictures can accompany texts in order to improve their comprehensibility and their memorability (pictures can also be added, of course, to make a text look more attractive and saleable). The picture may simplify complex information or make abstract information more concrete by conveying spatial, temporal or functional relationships in a simpler or more all-embracing way than linguistic information (Mandl & Levin, 1989, p. vii). Joel Levin (1989, p. 83) summed up almost a generation of research attention devoted to the problem of pictures in prose with the statement: Pictures interact with text to produce levels of comprehension and memory that can exceed what is produced from text alone. This would have proven controversial 20 years earlier when few empirical studies had been undertaken, and their results lacked consistency. Until 1970, researchers tended to conclude, perhaps contrary to common experience, that pictures do not aid learning, even for children, and that they could have a distracting, negative effect on occasions. It took some time for researchers to appreciate that it is insufficient to ask simply whether or not pictures enhance text. First, pictures with text can be used for many purposes, and at the very least it is necessary to distinguish between the role of pictures in learning

Computer Animation in an ln~tructional Environment 7

to read and their role in reading to learn; in general pictures were unhelpful (or even detrimental) in the former context but generally beneficial in the latter. Second, the pictures in the text should relate, in some way, to that text; the evidence strongly suggests that pictures that are irrelevant or, worse still, contradictory to the text have a negative effect. Third, general claims for pictures must be replaced with situation- specific claims that take into account the specific picture, text, learner, learning objective, and learning measure.

Levin (1981) identified five primary functions for pictures: decoration (unrelated to the text), representation (overlap with the text that makes the text more concrete), organization (add structure/~herence to the text), inte~retation (aid comprehension of a difficult text) and ~ansfo~ation (enhance memorability of the text by turning it into a more mnemonic form). Decorative pictures do not facilitate learning while transformational pictures produce the most substantial learning bene- fits. The suggestion that pictures make a text more enjoyable, resulting in positive attitudes towards reading in general and the illustrated text in particular, is not strongly supported by research (Peeck, 1987).

Levin and Lesgold (1978) discuss the research environment in which to investigate picture-text relationships. They conclude that there is solid evidence for pictures facilitating text learning when five experimental conditions are present: the subjects are children; the text is presented orally (this removes the effect of reading ability); the text passages are functional narratives (because it is easier to control narratives than factual info~ation for prior knowledge); the pictures overlap the text content; and learning is demonstrated by factual recall. In these conditions a positive effect for pictures exists across various methods of presentation (pictures simultaneously shown with text, following each sentence, following the text), across learner characteristics (gender, age (6-12)) social class, intellectual ability, text characteristics (length, complexity), and time. At least in the case of children, Levin (1981, p. 204) thought the effect of pictures on prose learning to be positive, potent and pervasive, story-relevant pictures leading to childrens ability to recall at least 40% more of the information in comparison with a no-picture control group. Some researchers have also found that pictures enhance text for adults (Anglin, 1986; Dwyer, 1972; Mayer, 1989). More recently, Mayer, Steinhoff, Bower, and Mars (1995) found that understan~ng a scientific text explaining a cause and effect system can be greatly improved, especially for less experienced learners, by annotating multiframe illustrations that portray step-by-step changes in the states of the parts of the system. However, this is rarely done in textbooks.

Despite the generally positive results for picture-enhanced texts compared with text alone, the definition of what constitutes effective text-picture combinations remains complex. Notwithstanding a large body of research findings, Molitor, Ball- staedt, and Mandl(lQ89) argue that cognitive research on text-picture design is still in its initial stages.

TELEVISION AS A LEARNING MEDIUM

Moving images (both animated and full motion) predate computer technology and interactive multimedia systems: they are both to be found, together with sound and occasionally text, on television broadcasts and videocassette. The television and the computer differ, however, in several salient respects. The television, unlike the

8 Large

computer, is a one-way communication device: normally it does not encompass intera~ti~ty on the viewers part. Equally important, television is primarily con- ceived (and perceived) as an entertainment rather than an educational or learning medium; the computer has a more varied role, encompassing learning as well as work and entertainment. The convergence of broadcasting and computer technologies, however, as well as the increasing use of computers for entertainment, especially by children, may blurr the distinction between television and computer programming content.

Researchers have investigated the instructional role of television, normally on children. Salomon (1984) found that the effectiveness of instructional television had a lot to do with the childrens preconceptions about the material. He suggests that Childrens inferential learning may depend on what they perceive the material to be and how efficacious they think they are with such materials. (p, 656) When children perceive materials as being easy and themselves efficacious, they may invest less mental effort and learn less well. Salomon and Leigh (1984) elaborate upon this observation. They report that when children do invest effort in television this appears to have a positive effect on recall (their ability to retrieve accurately from memory the content of the program), On the other hand, when children invest effort in reading printed material this serves inference generation (their abiity to draw inferences from the content of the program). Childrens preconceptions re- garding television appeared to affect the depth with which they processed its information, thereby fulfilling their own expectations. Salomon and Leigh found this differentiated pattern to be more pronounced among high-ability children. They were more likely to dismiss television as undemanding, expend less effort in processing its content, and learn less from it. They treated print materials more seriously and, therefore, learned more from it (see below for different results in the case of animation and text in a multimedia environment).

Boeckmann, Nessmann, and Petermandl(l988) examined some characteristics of educational video programs and their effect on recall. They found that the following factors did not influence recall: duration of shots; visibility or otherwise of sound source (that is, the commentator(s)), use of close-ups, long shots, or intermediate shots; and cutting or fading to successive shots. More surprisingly, they report that the presence of movement in a picture had minimal influence on recall. Predomi- nantly still or absolutely static pictures appeared to favor recall more than a high proportion of shots showing moving objects or produced by camera movement. In contrast, there was a positive relationship between content-related elements and recall, and especially the relationship between sound and image. A large proportion of the weaknesses in the eight video films they tested was attributable to deficiencies in the interaction of commentary and picture. Recall was stimulated when a close relationship existed between the information conveyed in the image and that in the commentary (analogous to the findings in the case of pictures and print). Addition- ally, retention was better when there was a high level of redundancy in the spoken commentary, and when it was more rather than less comprehensible. The researchers concluded that the text processing capacity of the viewer is limited and that processing the picture takes precedence over processing the commentary. The processing capacity remaining from dealing with the picture is not sufficient to digest commentaries which are semantically and syntactically dif~cult.

Computer Animation in an Instructional Environment 9

METHODOLOGICAL PROBLEMS

Researchers, especially from educational psychology and educational technology, are now exploring the problems of integrating animation into multimedia learning tools. In particular, attention has centered on whether the addition of animation enhances the educational value of a text, and how multimedia products can best be designed to maximize such enhancement. The results from multimedia studies, as well as earlier studies on computer-assisted instruction packages using other technologies, however, have been contradictory and inconclusive. Rachal (1993), for example, reviews 12 studies that compared adult basic and secondary education students taught using computer-~sisted ins~uction to similar students using traditional methods. Six studies showed no statistically significant differences between the two groups, four showed mixed results or failed to report statistical significance, and only two revealed statistically significant differences-one favoring Computer- Assisted Instruction (CAI) and one favoring traditional instruction. While some research has reported learning enhancement for a text accompanied by animation compared with an unaccompanied text, other research has found little or no positive effect for ~imation. It is evident that many researchers are surprised by these results, and muse over the probable explanations for the lack of animation effect (see, e.g., Caraballo Rios, 1985; and Rieber & Hannafin, 1988).

A major problem to be overcome in research on animation-text relationships is the number of variables to address. In the first place, both animation and text can vary according to a wide range of criteria. Some criteria related to animation are influenced by hardware as well as design considerations. Thus, animation may be in black or white, or in color, the pixel density (and, therefore, clarity of the image) can vary, and the image can occupy a full screen or only a part of a screen. The designer must decide upon the degree of realism versus stylization in an animation, the duration of the animation, whether it will be broken into more than one sequence, and, if so, whether the user will exercise control over the execution of each sequence. The animation might or might not be accompanied by a caption or orientation devices (such as pointing arrows) to direct viewer attention to events taking place within the animation. Text can vary in length, layout (font, spacing, etc.), type, and level of complexity. Texts are of three types (or a mixture of these types): narrative, descriptive, and procedural. Texts can also be categorized as complex or simple using various measures: reading level (itself based on semantic, syntactic and mor- phological characteristics), density of semantic networks, etc. If researchers choose one kind of animation and one kind of text with which to experiment, they may obtain results that are not transferable to other kinds.

The multimedia users (subjects) constitute a second element of variability. There is considerable research evidence that children may respond differently to multimedia instruction than older students. Other possible user variables are intellectual ability, spatial skills, and prior knowledge of the subject area being presented in the text and animation sequences. More will be said of these characteristics and their relationship to multimedia animation. Clark (1983) has pointed out another problem that may be encountered with subjects. They tend to give increased attention to new, novel media which might lead them to expend increased effort initially when the researchers conduct their investigations, and which yields initial achieve-

10 Large

ment gains. Such a novelty effect is unlikely to persist with more extensive use, however, and as it wanes the gains will diminish.

In order to assess any enhancement effect of animation upon text it is normal to test subjects on what they learned after viewing the multimedia information. Re- searchers have used different kinds of measures in such tests, providing a third area of variability between studies. Many researchers have sought to measure recall: subjects are asked to recall in their own words what they have learned. This recall might, in turn, then be re-analyzed to assess the subjects ability to draw inferences from the conveyed information, or to identify the main themes (frames) in the information (Large et al., 1994,1995). In other cases, subjects have been asked to answer multiple choice questions, or to complete a problem-solving task in order to gain measures of comprehension (Large et al., 1994,1996). Particularly with procedural texts (and accompanying animations) subjects may be asked to replicate the procedure to demonstrate comprehension (Large et al., 1995). These measures are partly related to the kind of information being conveyed (as in the procedural text example) and partly to the educational objective for which the multimedia aid is being applied: recall is a suitable test if, for example, the objective is for students to assimilate accurately the information and be able to recreate it verbally or in writing; problem-solving or procedure enactment might be a better measure if the objective is for the student to be able to apply acquired information to a problem. Some of these tests are written (or spoken); these may be biased in favor of written (that is, textual) rather than visual (a~mation) information.

A fourth variable is the time lag between viewing and testing. Many investiga- tors have tested subjects immediately or shortly after viewing. There is some research evidence to suggest that the enhancement effect of animation on text may be related to the length of elapsed time between viewing and testing, and that a delay of several weeks rather than several minutes would lead to different conclusions. In Peecks opinion (1989), the preference for immediate testing is both surprising and unfortunate. A different time variable relates to the duration of the experiment: in most cases subjects have been requested to use a multimedia source on one or two occasions (perhaps after an initial training session) and are tested after use. In a few cases, however, the study has been longitudinal: subjects work with a multimedia source on a regular basis over a period of time, and are tested either periodically or at the end of the completed project.

Choice of research environment poses a different methodological challenge. Some researchers have chosen to work with subjects in a real environment, typically the classroom. Students undertake genuine class projects using multimedia information sources, and the researchers observe, tape, and interview them. This technique offers a number of advantages. The students are at ease in a familiar setting. They are using a multimedia source within a specific educational context, and are required to extract information from it to fulfill real educational objectives and often real assignments. This can influence positively their motivation, in turn a factor linked to learning. Longitudinal studies are likely to be of this kind. The main drawback is the difficulty of exercising the kind of control that may be needed to produce reliable and repeatable research findings, In particular, subjects may gain information over the duration of the project from all kinds of sources other than the multimedia source which is being tested: control over prior knowledge, in other words, is difficult to ensure. Alternatively, researchers can opt for an experimental


environment. This could be the laboratory or the classroom: the setting is not especially important. What distinguishes the experimental environment is the strict control over as many variables as possible. Normally subjects are asked to view a specially selected text-animation sequence whose characteristics (in terms of length, type, complexity, etc.) have been predetermined. The subjects can be isolated one from another in order better to measure the extent to which a text alone might be enhanced by the addition of animation. The subjects themselves can also be prese- lected according to numbers and relevant characteristics (e.g., gender, reading level, or prior knowledge). The disadvantage lies in the artificiality of the experimental condition. The source and the tests are likely to be unrelated to the subjects current educational program (so as to control for prior knowledge), thus perhaps adversely affecting motivation. The multimedia sequences are likely to be short and viewed outside any context (Large et al., 1994). As Yildiz and Atkins (1993, p. 134) say, whether the results achieved can actually be replicated in real classrooms remains an open issue.

The sample sizes of subjects must be large enough to generate statistically reliable data. Depending upon the number of within and between variables, the sample size may have to be quite large. For example, if it is necessary to divide subjects into several groups, each of which views a different text/animation sequence (differentiated, e.g., by complexity, reading level, and type), and if each group must include subjects exhibiting one of several characteristics (e.g., gender, spatial ability, and reading ability), then it will be necessary to assemble a large subject sample to achieve statistically significant results, not always logistically feasible, especially in an experimental mode. The methods used to select the sample must be carefully controlled to eliminate the danger of extraneous factors influencing the results.

In addition to these methodological problem areas, a number of critics have pointed to basic flaws that all too easily can appear in attempts to evaluate the effectiveness of educational technologies (that is to say, the extent to which they facilitate learning). At issue is the question of whether media (tape/slide, television, multimedia, or whatever kind of programming) influence learning, or whether they are mere vehicles that deliver instruction but do not influence student achievement any more than the truck that delivers our groceries causes changes in our nutrition (Clark, 1983, p. 445). Levie (1987, p. 21) reports that Media research has a troubled past and an uncertain future. The advent of each new teaching technology has spawned an outbreak of research hoping to demonstrate the superiority of the new medium to conventional instruction. Repeatedly, these hopes have been dashed, When researchers try carefully to control all variables except the two media being compared, there is a likelihood that no media effect will be discovered. Alterna- tively, if there are differences between the two media (e.g., in content) then it can be difficult to know whether it is the medium or the content that accounts for any identifiable learning outcome differences. Yildiz and Atkins (1993) characterize media evaluation research between the 1950s and the early 1970s as being comparative in format: typically the studies were designed to minimize the differences between the treatment of the content in the control and the experimental groups so that any difference in the experimental group could be clearly attributed to the new technology. The most common result was to find no significant difference between the two groups in learning. Later research on media evaluation recognized this

12 Large

shortcoming and focused attention on the relationship between the learner, the media and the task, rather than the media alone.

The early research on interactive video in the mid-1980s, however, tended again to employ the earlier comparative methodology. As a leading critic of these kinds of studies has commented, the evidence is overwhelming that media do not influence achievement (Clark, 1991, p. 37). A technology such as multimedia can potentially make a difference to instructional effectiveness, but only if its attributes enable it to present information in a new way that is relevant to the learning experience and the instructional objective. In the case of multimedia animation, for example, its potential to show objects in motion may have an effect which cannot as easily be produced by other media, and the measurement of such an effect could be offered as support for the use of multimedia when dealing with information including a motional content. That this debate continues is evidenced by the recent articles in Educational Technology Research and Development on the influence (or otherwise) of media on learning (Clark, 1994a; Clark, 1994b; Jonassen, Campbell, & Davidson, 1994; Kozma, 1994a; Kozma, 1994b; Morrison, 1994; Reiser, 1994; Ross, 1994; Shrock, 1994; Tennyson, 1994).

ANIMATION RESEARCH

Animation is now de rigeur in multimedia, but its realization, even in products designed for an educational market, often has more to do with impressing potential buyers and users than with successful instruction. As Hannafin, Phillips, and Tripp (1986, p. 134) comment, The rationale for design...appears to have evolved largely through intuitive beliefs paired with the trial and error experiences of designers. They add that many of the tacit assumptions about effectiveness have little or no empirical foundation. Rieber (1989b) draws a similar conclusion. A body of research is now accumulating, however, on the effectiveness of multimedia as an instructional tool, and particularly on the role that animation can play in enhancing textual information. Unfortunately, the methodologies on occasion were prone to the problems outlined above, and the results have not always been consistent. Nevertheless, there is progress toward the enunciation of design criteria for effective instructional multimedia. This section summarizes the findings.

Attention-Gaining

Any successful instructional approach, including multimedia, must be able to gain the attention of the student (Park & Gittelman, 1992). Animation, through the employment of movement and color is well-placed to arouse student interest, especially for younger subjects. Rieber (1990b) mentions special screen washes, special effects for transitions among various parts of the instructional program, moving symbols, animated prompts, etc. Taylor (1992) ranks the following media combinations in increasing order of attention-holding: text only, static images, animated and static images, sound, sound and animation. The power of animation to attract attention is a potential problem, however, as it can distract from an accompanying text. Viewers may also be irritated and their attention lost if their high expectations from animation are not fulfilled by the product as a whole. Attention-grabbing can be a


diminishing resource: novelty wears off. According to Rieber (1989b), the longterm motivational effect of animation as a means to increase student perseverance has little empirical support. The multimedia product must be capable of achieving its objective once the novelty of animation has become mundane.

Semantic Overlap

Attention-gaining should be distinguished from purely cosmetic devices which are merely intended to make the program more attractive. An interesting animation which is irrelevant to the program content may still gain the learners attention, to be sure, but there is a real danger that it will distract attention from the task at hand. The content portrayed in the animation must overlap with that in the text to gain benefit from the animations inclusion. The importance of semantic overlap may seem obvious, but, in fact, this principle is found wanting in many well-known and praised multimedia products. Alesandrini (1987) surveyed 60 computer-based instruction lessons and found that in areas other than math only a small percentage displayed relevant graphics more than half the time.

Design Features

Animation sequences can be designed in many different ways. Designers must decide on color: monochrome or color (and the size of the palette); pixel density; size (full screen or less); duration; sequencing (whether to break a sequence into several steps); degree of realism (how stylized should the image be), and so on. Hardware considerations influence many design decisions. More research needs to be undertaken before it will be possible to establish clear guidelines on these issues. Certainly, it should not be assumed that more realistic images necessarily produce better learning effects. Research from television learning (Salomon & Gardner, 1986) suggests that familiar and realistic images may reduce the viewers perception of the effort needed to process the information, thereby reducing the depth of processing. More detailed animation sequences may confuse rather than clarify, and may also tend to distract attention from important information conveyed, for example, by text or sound. Hannafin and Phillips (1987) agree that detail may not always facilitate learning and that color can both attract and distract viewers, but they add that learners often prefer visuals that contain extensive details. The important factor here is probably the relevancy of the detail. If the detail contributes to the target knowledge then it is positive, but detail for its own sake will tend only to distract. Hannafin and Rieber (1989) believe that the more concrete the animation, the easier it is to picture and remember; the less concrete, the harder to picture and remember.

Color of itself does not seem to be a critical variable. Rieber (1994) for example, argues that at best color serves only to help in directing attention to some critical feature in the display. Even here, he thinks that it is not color per se but the potential contrast that color provides that is important. Color can increase motivation but also cause distraction. Baek and Layne (1988) detected no effect for color in their study of 9- to lZyear-old students, even though the students found the color version more appealing.

14 Large

Content

For Alty (1993, p. 51, what matters in designing a multimedia interface is the nature of the information needed by the users to carry out their tasks. Deciding which medium has characteristics which best transmit such information is then a key aspect of the design process. Park and Gittelman (1992) advise that both animated and static visuals facilitate learning only when their attributes are applied in congruence with the specific learning requirements of the given task, and that they therefore should be se- lectively applied. Congruency between the learning task and lesson presentation was established as a rule for predicting a positive effect for pictures. The same would be expected for animation. As Rieber (1991) argues, animation provides external visualization (like any picture), but its special attribute is to provide motion and trajectory (the direction of travel of a moving object). Animation might, therefore, be expected to help with learning tasks involving changes over time or of direction, and especially with dynamic processes that cannot easily be visualized (e.g., the sequence of leg movements as a horse gallops). Despite a suggestion from one television research study that motion did not improve recall (see above), in general there is agreement from multimedia researchers that motion is an attribute of animation that can enrich the learning experience (Large et al., 1996; Park & Gittelman, 1992; Rieber, 1990a). An ability to show motion differentiates animation (as well as full-motion video) from still images (both can equally well provide visualization). Spangenberg (1973) investigated specifically the effects attributable to motion in teaching a procedural task: how to disassemble a machine gun. He found that the subjects viewing a videotape per- formed better than those viewing a set of still images, although when he redesigned the still images he was able, with some sequences, to improve learning to the level achieved by the subjects viewing the animation. Hannafin and Phillips (1987, p. 49), however, caution that it may be premature to conclude that video is either the only, or necessarily the preferred, method for conveying motion. They point out that lit- eral demonstration of motion may deter students from directing sufficient mental effort to process the animation, thereby undermining their ability to construct their own mental images. Animated motion which represents rather than faithfully reproduces motion may also be misleading. For example, an animated representation of a chemi- cal reaction may produce a mental image in the viewer, but that viewer must then appreciate that the image is stylized rather than actually representational. Park and Gittelman (1992) suggest five specific instructional conditions in which visual motion can be used: demonstrating procedural actions (see below); simulating system behav- iors; explicitly representing invisible movements; illustrating structural, functional, and procedural relationships among objects and events; and focusing the learners attention on important concepts.

A large body of evidence suggests that redundancy is positively related to learning. Students seem to prefer parallel sets of redundant information rather than unique sets of info~ation. As long as the information presented in different media is consistent and relevant, its repetition across several media is positive.

Subjects

The importance of individual differences in subject characteristics on learning has been one of the major themes in the history of educational research (Jih & Reeves,


1992). Three individual differences influence learning: personal factors such as prior knowledge and experience; affective factors such as motivation and attitude; and physiological factors such as eye-hand coordination and visual acuity. Animation research has been conducted with subject groups such as: primary school children, high school children, undergraduates, and military personnel. There could be several reasons for the finding that children may respond more positively to animation than do older subjects. Children, of course, tend to be more used to viewing animations than their older counterparts, and may be more attracted to information in this medium. Children may also find textual information more difficult to process, through lack of practice as well as less developed vocabularies and reading skills. Though our ability to visualize may be innate, children are not as good as adults at generating spontaneously internal images; it is an ability which can be nurtured. Children are also less familiar with their external environments and therefore more likely to benefit from visualization {whether by still or moving images) of textual content than adults who may already have a visual image of the object being described in the text. In general, adults store, retain and retrieve information better than children, because developmental advances in the context and structure of their semantic or conceptual systems make information more familiar, meaningful, and conceptually interrelated for adults (Flavell & Wellman, 1977). Adults are better able than children to form internal images from carefully designed and highly imageable textual explanations, and have less need of visuals-either animated or still (Rieber, Boyce, & Assad, 1990).

One note of caution should be sounded when discussing differences between children and adults in terms of multimedia instructional effectiveness. The overwhelming majority of studies on use of multimedia by adults investigated subjects who are textually literate and used to retrieving information from textual sources: principally undergraduate or graduate students. It would be interesting to find out how less-literate adults would benefit from the provision of instructional information in a visual rather than textual format. The perceived differences found in research studies between children and adults responses to visual information may really be differences between less literate and more literate learners rather than younger and older learners.

A number of researchers have identified subjects ability as influencing the effectiveness of animation. Reed (1985), in an experiment using algebra problems, argues that students with less ability need additional feedback in order to benefit from computer graphics. Blissett and Atkins (1993) report on a study of 12- to 13-year-old students using an interactive videodisc to improve understanding of the mathematical concept of probability. They comment that for the full learning benefit to occur students had to bring a sophisticated understanding of the task into play. Those with less prior knowledge, less ability, or less flexibility as learners tended to find the learning demands confusing (admittedly, they are discussing the interactive as well as animation attributes). These findings are in accordance with those of Reid and Beveridge (1990) for still images: illustrated texts improved the performance of the more successful children. They were able to identify and integrate relevant information from both texts and images, and were not distracted from the text by the images. The less successful children looked at the images both more frequently and for a greater proportion of the time they spent on the topic, and had more difficulty in integrating pictorial and textual info~ation.

16 Large

Spatial visualization skills also appear to be a relevant subject variable. For Mayer and Sims (1994), spatial visualization is the ability mentally to rotate or fold objects in two or three dimensions and to imagine the changing configurations of objects that would result from such manipulations. Large et al. (1996) found that primary school students with higher spatial visualization skills gained more benefit from the presence of animation with text than their counterparts with lower spatial abilities. Supporting evidence comes from Hegerty and Sims (1994), although in this case subjects were shown a still image (a diagram) rather than an animation. They found a statistically significant relationship between accuracy in a reasoning task dealing with the motion of a component in a mechanical system and spatial visualization ability among undergraduates. In other words, visual representations appear to help those subjects who already have good visualization skills more than those subjects who have more difficulty in visualizing.

Many researchers have noted wide variations in performance between individual subjects within a group (undergraduates, Baggett, 1987; primary school students, Large et al., 1994, 1995, 1996). More research, however, is needed. As Yildiz and Atkins (1993, p. 135) state, the differential effects of designs according to learner characteristics such as gender, age, social background and prior achievement-the staples of research in other areas of education- remain under-represented in media evaluations.

Text Type

Large et al. (1994,1995,1996) distinguish between procedural and descriptive texts. Procedural texts present a series of actions which are executable by someone or something in order to attain a specific goal. Descriptive texts describe an object, scene, or location. They found that in general animation improves the comprehension of a procedural text more than a descriptive text. Procedural texts, of course, are more likely than descriptive texts to require animation that demonstrates motion or trajectory (see above).

Complexity

For Park and Gittelman (1992), one of the three primary instructional roles of animation is to help explain complex knowledge or phenomena. In a study of undergraduate students they found that animation helped to illustrate complex structural, functional, and procedural relationships among objects and events. On the other hand, in a study of primary school children and an animated text on Newtons laws of motion, Rieber (1989a) did not find an effect for animation. He explains this, in part at least, by the difficulty of the material. When the experiment was repeated but with a simplified content (Rieber, 1990a; Rieber & Hannafin, 1988) a positive effect for animation was found. Rieber maintains that one condition for the effective use of animation to elaborate a lesson is that its content be neither too complex nor too simple. Alty (1993) agrees with this finding. A simple concept can be conveyed in almost any medium. On the other hand, a very complex concept might be so difficult to grasp that whatever combination of media are used the presentation will fail. Between these extremes, he argues, comprehension can be influenced by the medium. Large et al. (1994) offer a similar explanation for the


failure of animation accompanying complex textual material. An animation cannot necessarily compensate for such textual complexity, especially if the animation itself is also complex. They found, to their surprise, that animation was more effective when accompanying simple rather than complex texts.

Familiarity

According to Hale, Oakey, Shaw, and Burns (1985), animation has most value for students if the events depicted are unfamiliar to them. It is less necessary if they already have a mental image of these events. Rieber (1989b), on the other hand, believes that research evidence suggests that when learners are novices in the content area they may not spot relevant cues or details provided by animation as well as more advanced learners.

Chunking

Rieber (1989b) emphasizes the importance of breaking down a frame of instruction into its component chunks of information. Each chunk should contain information in one medium only-text, still image, animation, and sound. Each chunk should be displayed individually. He argues that this helps subjects to focus their attention on the animated displays. Mayer and Anderson (1992), on the other hand, argue in favor of the contiguity principle which is derived from the dual coding theory: multimedia inst~~tional effectiveness increases when words and pictures are presented contiguously in space and time rather than isolated from one another. Failure to do so disrupts the building of inferential connections. They found (1994) that inexperienced students were better able to transfer what they had learned from a procedural text about a scientific system when visual and verbal explanations were presented concurrently rather than separately.

Orientation

It is important that the attention of the viewer is drawn to the relevant motion taking place in the animation (Rieber, 199Oa). This can be unde~aken in a variety of ways such as: pointing arrows, captions, and labels. Young children, especially, appear to need queuing to the relevant action in the animation if they are to learn from it. Spangenberg (1973) found that the use of animated arrows to direct attention and to show the direction of motion did not help learning. Large et al. (1996) did not find that captions improved the effectiveness of animations accompanying texts. They believe that this lack of effect may be explained, however, by the provision within the animation sequences of labelling and pointing arrows that made the captions redundant.

Interactivity

The idea behind interactive learning is that the learner should be an active rather than a passive participant in the teaching-learning process. Rieber (199Ob) created an interactive simulation on Newtons laws of motion in which students were given control over an animated starship. When children were the subjects, the group that

18 Large

was able to practice dynamically with the animation achieved better learning results than the noninteractive control group. In the case of adults, although the interactive group produced similar results to the control group, it required significantly less time to answer post-test questions than the noninteractive group.

Learning objective

Large et al. (1994,1995,1996) found that grade-six primary school students bene- fited from the addition of animation according to the learning objective. When the task was to recall accurately information that had previously been studied, text alone seemed most effective. It was hy~thes~ed that they were not distracted by additional information contained in images. Furthermore, they were not faced with the additional cognitive task of merging information acquired from several media. When the students were asked to draw inferences from the information, however, animation accompanying the text improved performance. This improvement was even more marked when the students were asked to replicate a procedure or accomplish a problem-solving task.

Perzylo and Oliver (1992) found that primary school children were attracted to the most visually and auditorially stimulating information, and sound followed by video were the most popular media, although the students became easily distracted when viewing long video sequences. The students were not inclined to read and digest the textual information, and the most carefully read text sequences were the captions accompanying the images. Nevertheless, the info~ation gained from the text was the most widely used for writing the paper which was the immediate educational objective. Perzylo and Oliver point out that students may find it difficult to transform information gained visually (or aurally) into textual information in a written assignment.

CONCLUSION

According to Rieber (1991), even in its best form, animated instruction exerts a relatively subtle influence on learning and many factors can undermine its effectiveness. He warns that designers and developers must be careful not to confuse the dramatic visual effects of animation with its related effects on learning. For Mayer and Anderson (1992) a research-based theory is still lacking on how to design multimedia instruction using words and pictures. In a review of 63 studies investigat- ing interactive video (IV), McNeil and Nelson (1991, p. 5) conclude that the variance in results indicates that cognitive achievement from IV is influenced by a myriad of (sic) variables that are difficult or impossible to account for.

Despite such hesitations on the part of researchers, evidence is now accumulating about how animation might best be employed so as to maximize its instructional potential in interactive multimedia environments. Clearly, it is insufficient simply to add any animation to any textual information and expect that an effective learning tool has been created. Certain design criteria are emerging. The animation must complement the text by presenting the same semantic content in two media: the media should not be used to provide separate, albeit related, information, and certainly not to present conflicting information (which does happen in commercially available products). Strong evidence is accumulating that children respond more positively than adults to


animation. Furthermore, those children with ability and visualization skills appear to benefit more from animation-enhanced text than those who are lacking these attributes. Animation can grab a users attention, but the novelty effect is short-live& animation must offer more than this to work well. Any visual information-still or moving-can serve a representational function; the special quality animation can offer is to demonstrate motion and trajectory. Even this must be done with care, however, lest the animation distract from any accompanying text. Animation also seems to be particularly useful in presenting procedural information, but it does not necessarily aid in the assimilation of textual information which is very complex: a better strategy here would be to simplify and clarify the text. More research is needed on design criteria such as the use of color, labeling, orientation, and degree of realism in images before firm conclusions can be drawn. Finally, the instructional task is important in determining the suitability of multimedia. The delivery of information to a subject so that it can be accurately recalled may benefit little from animation compared with text alone: indeed, animation may reduce recall (Large et al., 1994). Procedural replication or problem-solving tasks, on the other hand, may benefit considerably from the presence of animation as well as text.

Animation and text in an interactive multimedia environment seem here to stay regardless of research results that contradict the more ambitious claims made for them. The objective of research is to establish design criteria that will enable such multimedia instructional products to function most effectively as learning tools. Progress is being made towards this goal, but much work still lies ahead.

REFERENCES

Alesandrini, Kathryn Lutz. (1982). Imagery-eliciting strategies and meaningful learning. Journal of Mental Imagery, 6 (l), 125-140.

Alesandrini, Kathryn L. (1987). Computer graphics in learning and instruction, In Harvey A. Houghton & Dale M. Willows (Eds.), The psychoZogy of illustration, VoZ 2, Z~tr~ctionuZ issues (pp. 159-188). New York: Springer.

Alty, James L. (1993). Multimedia: We have the technology but do we have a methodology? Educational Multimedia and Hypermedia Annual, 1993: Proceed- ings of Ed-Media 93-World Conference on Educational Multimedia and Hyper- media, Orlando, Florida, June 1993 (pp. 3-10). Orlando: Association for the Advancement of Computing in Education.

Anglin, Gary. (1986). Prose-relevant pictures and older learners recall of written prose. EdueutZonuZ Communicution and Technology JournuZ, 34,131-136.

Baek, Young K., & Layne, Benjamin H. (1988). Color, graphics and animation in a computer-assisted learning tutorial lesson. Journal of Computer-Bused Znstruc- tion, 15,131-135.

Baggett, Patricia. (1987). Learning a procedure from multimedia instructions: The effects of film and practice. Apptied Cognitive Psychology, 1,183-195.

Bartlett, John. (1980). Familiar quotation. (15th ed.). Boston: Little, Brown. Bennett, Hugh. (1994). To instruct and delight: Childrens and young adults litera-

ture on CD-ROM. CD-ROM Professional, 7 (4), 84-94. Blissett, Gillian & Atkins, Madeleine. (1993). Are they thinking? Are they learning?

A study of the use of interactive video. Computers in Education, 2I,31-39. Boeckmann, R., Nessmann, K. & Petermandl, M. (1988). Effects of formal features

20 Large

in educational video programs on recall. Journal of Educational Television, I$, 107-122.

Caraballo Rios, Angel Luis. (1985). An experimental study to investigate the effects of computer animation on the understanding and retention of selected levels of learning outcomes. Unpub~shed doctoral dissertation Philadelphia Pennsylva- nia State University.

Clark, Richard E. (1983). Reconsidering research on learning from media. Review of Educational Research, 53,445-459.

Clark, Richard E. (1994a). Media will never influence learning. Educational Tech- nology Research and Development, 42 (2), 21-29.

Clark, Richard E. (1994b). Media and method. Educat~na~ Technology Research and Development, 42 (3), 7-10.

Dwyer, Francis M. (1972). A guide for improving visualised instruction. State Col- lege, PA: Learning Services.

Edison, Thomas Alva. (1921). The diary and observations of Thomas Alva Edison. Quoted in American Libraries, (1995) 26,503.

Flanders, Bruce. (1992). IBMs impressive multimedia educational programs. CD- ROM Librarian, 7 (l), 32-36.

Flavell, John H. & Wellman, Henry M. (1977). Metamemory. In Robert V. Kral & John W. Hagen (Eds.), Perspectives on the development of memory and cognition (pp. 3-33). Hillsdale, NJ: Erlbaum.

Fryer, B, (1994). Multimedia training. Multimedia World, I (7), 55-59 Gagne, Ellen. (1985). The cognitive psychology of school learning. Boston: Little,

Brown. Glenberg, Arthur M., & Langston, William E. (1992). Comprehension of illustrated

text: Pictures help to build mental models. Journal of Memory and Language, 31,129-151.

Hale, Michael E., Oakey, James R,, Shaw, Edward L., & Burns, Joseph. (1985). Using computer animation in science testing. Computers in Schools, 2,83-90.

Hannafin, Michael J., & Phillips, Timothy L. (1987). Perspectives in the design of interactive video: Beyond tape versus disc. Journal of Research and Develop- ment in Education, 21,44-60.

Hannafin, Michael J., Phillips, Timothy IL., & Tripp, Steven D. (1986). The effects of orienting, processing and practicing activities on learning from interactive video. Journal of Computer-Based Instruction, 13,134139.

Hannafin, Michael, & Rieber, Lloyd P. (1989). Psychological foundations of instructional design for emerging computer-based instructional technologies: Part II. Educational Technology Research and DeveZopment, 37 (2), 102-114.

Hegarty, Mary, & Sims, Valerie K. (1994). Individual differences in mental animation during mechanical reasoning. Memory and Cognition, 22,411-430,

Howson, Betty Ann, & Davis, Hilarie. (1992). Enhancing comprehension with videodiscs. Media and Methods, 28 (3), 12-14.

Jih, Hueyching Janice, & Reeves, Thomas Charles. (1992). Mental models: A research focus for interactive learning systems. Educational Technology Research and Development, 40 (3), 39-53.

Jonassen, David, Campbell, J., & Davidson, M. (1994). Learning with media: Re- structuring the debate. Educational Technology Research and Development, 42 (2) 31-39.


Kozma, Robert B. (1994a). Will media influence learning? Reframing the debate. Edu~ationaZ Technology Research and Development, 42 (Z), 7-19

Kozma, Robert B. (1994b). A reply: Media and methods. Educations Technology Research and Development, 42 (3), U-14.

Large, Andrew. (1985). The artificial language movement. Oxford: Blackwell. Large, Andrew, Beheshti, Jamshid, Breuleux, Alain, & Renaud, Andre. (1994).

Multimedia and comprehension: A cognitive study. Journal of the American Society for Information Science, 45,515-528

Large, Andrew, Beheshti, Jamshid, Breuleux, Alain, & Renaud, Andre, (1995). Multimedia and comprehension: The relationship among text, animation and captions. Journal of the American Society for Information Science, 46,340-347

Large, Andrew, Beheshti, Jamshid, Breuleux, Alain, & Renaud, Andre. (1996). The effect of animation in enhancing descriptive and procedural texts in a multimedia learning environment. Jou~l of the American Society for Znformation Science, 47.

Levie, W. Howard. (1987). Research on pictures: A guide to the literature. In Dale M. Willows & Harvey A. Houghton (Eds.), The psychology of illustration, Vol I: Basic research (pp. l-50). New York: Springer.

Levin, Joel R. (1981). On functions of pictures in prose. In Francis J. Pirozzolo & Merlin C. Wittrock (Eds.), ~europsychological cognitive processes in reading (pp. 203-228). New York: Academic.

Levin, Joel R. (1989). A transfer-appropriate-processing perspective of pictures in prose. In H. Mandl & J.R. Levin (Eds.), Knowledge acquisition from text and pictures (pp. 83-100). Amsterdam: Elsevier.

Levin, Joel R., & Lesgold, Alan M. (1978). On pictures in prose. Educational Communications and Technology Journal, z&233-243.

McNeil, Barbara J., & Nelson, Karyn R. (1991). Meta-analysis of interactive video instruction: A ten year review of achievement effects. Journal of Computer- Based Instruction, 18 (l), l-6.

Mandl, H., & Levin, J.R. (1989). Knowledge acquisition from text and pictures. Amsterdam: Elsevier.

Mayer, Richard E. (1989). Systematic thinking fostered by illustrations in scientific text. Journal of Educational Psychology, 81,240-246.

Mayer, Richard E., & Anderson, Richard B. (1992). The instructive animation: Helping students build connections between words and pictures in multimedia learning. Journal of Educational Psychology, 84,444-452.

Mayer, Richard E., & Sims, Valerie K. (1994). For whom is a picture worth a thousand words? Extensions of a dual-coding theory of multimedia learning. Journal of Educational Psychology, 86,389-401.

Mayer, Richard E., Steinhoff, Kathryn, Bower, Gregory, & Mars, Rebecca, (1995). A generative theory of textbook design using annotated illustrations to foster meaningful learning of science text. ~duca~onaL Technology Research and De- velopment, 43,31-41.

Molitor, Sylvie, Ballstaedt, Steffen-Peter, & Mandl, Heinz. (1989). Problems in knowledge acquisition from text and pictures. In H. Mantel & J.R. Levin (Eds.), Knowledge acquisition from text and pictures (pp. 3-35). Amsterdam: Elsevier.

Morrison, Gary. (1994). The media effects question: Unresolveable or asking the right question. Edu~a~~l Tech~~o~ Research and Developments 42 (2), 41-44.

22 Large

Paivio, Allan. (1971). Imagery and verbal processes. New York: Rinehart & Win- ston.

Paivio, Allan. (1986). Mental representations: A dual coding approach. New York: Oxford University Press.

Park, Ok-Choon, & Gittelman, Stuart S. (1992). Selective use of animation and feedback in computer-based instruction. Educational Technology Research and Development, 40 (4), 27-38.

Peeck, Joan (1987). The role of illustrations in processing and remembering illustrated text. In D.M. Willows & H.A. Houghton (Eds.), The psychology of illustration, Vol 1: Basic research (pp. 115-151). New York: Springer.

Peeck, Joan. (1989). Trends in the delayed use of information from an illustrated text. In H. Mandl & J.R. Levin (Eds.), Knowledge acquisition from text and pictures (pp. 263-277). Amsterdam: Elsevier.

Perzylo, Lesa, & Oliver, Ron, (1992). An investigation of childrens use of a multimedia CD-ROM product for information retrieval. Microcomputers for Znfor- mation Management, 9,225-239.

Pressley, Michael. (1977). Imagery and childrens learning: Putting the picture in developmental perspective. Review of Educational Psychology, 47,585-622.

Pressley, Michael, & Miller, Gloria E. (1987). Effects of illustrations on childrens listening comprehension and oral prose memory. In Dale M. Willows & Harvey A. Houghton (Eds.), The psychology of illustration, Vol 1: Basic research (pp. 87-114). New York: Springer.

Prickett, Elaine Montoya. (1992). The multimedia classroom. In Randall Boone & Kyle Higgins (Eds.), Multimedia (pp. 56-65). Reston VA: Council for Excep- tional Children.

Pylyshyn, Zenon. (1981). The imagery debate: Analogue media versus tacit knowledge. Psychological Review, 88,1645.

Rachal, John R. (1993). Computer-assisted instruction in adult basic and secondary education: A review of the experimental literature, 1984-1992. Adult Education Quarterly, 43,165-172.

Reed, Stephen K. (1985). Effect of computer graphics on improving estimates to algebra word problems. Journal of Educational Psychology, 77,285-298.

Reid, David. J., & Beveridge, M. (1990). Reading illustrated science texts: A micro- computer based investigation of childrens strategies. British Journal of Educa- tional Psychology, 60,76-87.

Reiser, R. (1994). Clarks invitation to dance: An instructional designers response. Educational Technology Research and Development, 42 (2), 45-48.

Riebes, Lloyd P. (1989a). The effects of computer animated elaboration strategies and practice on factual application learning in an elementary science lesson. Journal of Educational Computing Research 5,431-444.

Rieber, Lloyd P. (1989b, February). A review of animation research in computer- based instruction. Annual Convention of the Association for Educational Com- munications and Technology, Dallas, TX.

Rieber, Lloyd P. (1990a). Using computer animated graphics in science instruction with children. Journal of Educational Psychology, 82,135-140.

Rieber, Lloyd P. (1990b). Animation in computer-based instruction. Educational Technology Research and Development, 38 (1) 77-86.

Rieber, Lloyd P. (1991). The effects of visual grouping on learning from computer


animated presentations. Annual Convention of the Association for Educational Communications and Technology (ERIC ED335006).

Rieber, Lloyd P. (1994). Computers, graphics and learning. Madison, WI: Brown & Benchmark.

Rieber, Lloyd P., Boyce, Mary J., & Assad, Chahriar. (1990). The effects of computer animation on adult learning and retrieval tasks. Journal of Computer- Based Instruction, 17 (2), 46-52.

Rieber, Lloyd P., & Hannafin, Michael J. (1988). Effects of textual and animated orienting activities and practice on learning from computer-based instruction. Computers in Schools, 5 (l/2), 77-89.

Ross, Steven M. (1994). From ingredients to recipes...and back: Its the taste that counts. Educational Technology Research and Development, 42 (3) 5-6.

Salomon, Gavriel. (1984). Television is easy and print is tough: The differential investment of mental effort in learning as a function of perceptions and attribu- tions. Journal of Educational Psychology, 76,647-658.

Salomon, Gavriel, & Gardner, 0. (1986). The computer as educator: Lessons from television research. Educational Researcher, 1.5 (l), 13-19.

Salomon, Gavriel, & Leigh, Tamar. (1984). Predispositions about learning from print and television. Journal of Communication, 34,119-135.

Shrock, Sharon. (1994). The media influence debate: Read the fine print, but dont lose sight of the big picture. Educational Technology Research and Develop- ment, 42 (2), 49-53.

Simpson, Mark S. (1994). Neurophysiological considerations related to interactive multimedia. Educational Technology, Research and Development, 42 (l), 75-81

Spangenberg, Ronald W. (1973). The motion variable in procedural learning. AV Communication Review, 21,419-436.

Taylor, C. David. (1992). Choosing a display format for instructional multimedia: Two screens vs one. Association for Educational Communication and Technol- ogy (ERIC ED 348029).

Tennyson, Robert D. (1994). The big wrench vs. integrated approaches: The great media debate. Educational Technology Research and Development, 42 (3), 15- 28.

Yildiz, Rauf, & Atkins, Madeleine. (1993). Evaluating multimedia applications. Computers in Education, 21 (l/2), 133-139.

Documents

Computer Animation in an Instructional Environment 1996 1997 Library Information Science Research