Medical students must learn a great quantity of physiological and pathophysiological processes, surgical procedures and therapeutic interventions. Increasingly, instructors have turned to technology-assisted materials such as animations to provide students with the most accurate representations of these processes and techniques.1 Animations, which consist of a series of dynamic, graphical elements that represent real-world phenomena, present a complex concept in an efficient manner by substituting long textual descriptions with images in motion.2 Compared with static images or textual descriptions, animations ‘analyse processes and movements, simplify complexities through the use of symbols, emphasise pertinent information through the use of colour, highlight through changes in speed, stress action with sound’.3 Therefore, animations create an experience that is both engaging and instructive.
Animations that have positive learning effects may be difficult to construct because of the complex subject matter involved and the technical skills required to create high-quality computer-based animations. For this reason, educators may use existing animations to present educational content. In medical domains, examples of instructional animations include a demonstration of epithelia and their attributes (i.e. shape of cells, location in organs),4 a dynamic histological process such as bone formation during embryogenesis,4 three-dimensional animations of cleft lip and palate surgical techniques,5 and ocular anatomy and technical skills in cataract surgeries.6 Given the usefulness of animations in conveying complex information and the large body of research indicating that animations that follow certain empirically established design principles facilitate learning of medical and other scientific material, it is our goal to assess the extent to which existing animations adhere to these principles and how instructors can select and develop effective animations.2,7,8
Instructional design principles in animation development
The main design guidelines for animations are grounded in the cognitive theory of multimedia learning (CTML).8 To the authors’ knowledge, there are no other comprehensive theories of multimedia design. Despite the rapid changes in the instructional technology adopted in medical education, CTML is a useful framework because it has extensive empirical support and builds on other established theories, such as dual coding theory9 and cognitive load theory,10 to help explain and predict a variety of learning outcomes. According to dual coding theory, images and words are processed in separate, limited-capacity channels of working memory before becoming integrated into a single, coherent mental model, which is an organised conceptual framework of the subject matter at hand.8,9 Verbal and pictorial components provide unique contributions to mental model formation: words contribute theory-based information, such as explanations of complex relations, and images contribute similarity-based information, such as exemplars or other basic visual representations.11 The generative process of combining these theory-based and similarity-based elements to construct a detailed mental model helps learners solve related problems and anticipate future events in that context.12,13 Thus, animations that use words and images appropriately are potentially ideal tools for aiding student learning.
Also linked to CTML, cognitive load theory incorporates learners’ cognitive capacity for forming mental models into the designing of instructional materials, such as animations.10,14 An effective animation contains sequences of motion frames and presents the essential attributes of a concept in a manner that facilitates learning.15 Animations that accomplish this goal are designed with the learner’s cognitive capacity in mind and aim to optimise the balance among three types of cognitive demand: essential processing; extraneous processing, and generative processing.14,16 Each type of processing imposes a different type of load for the learner, and each needs to be addressed in a specific manner to facilitate learning. Essential processing, which imposes intrinsic load, is the cognitive processing inherently required by the nature of the task to mentally represent the lesson content. Extraneous processing, which imposes extraneous load, involves inefficient mental activities in which learners engage when faced with irrelevant or ineffective learning situations (e.g. distracting sound effects and images that are separated from their verbal descriptions). Generative processing, which imposes germane load, occurs when the learner creates a coherent mental model of the subject at hand. This type of processing, although effortful, is necessary for the learner to understand the topic as well as the overall learning domain. The instructional design of animations should attempt to manage essential processing, minimise extraneous processing and facilitate generative processing.16 In the following paragraphs, we discuss in more detail how this balance can be achieved.
The cognitive theory of multimedia learning provides several evidence-based learning principles that instructors should follow to optimise processing demands and facilitate learning.8,17 Although there are many principles of CTML, for space considerations we will restrict our discussion to eight principles which are among the most empirically supported and easily implemented in terms of their ability to support the management of essential processing, reduce extraneous processing and facilitate generative processing. Studies supporting CTML have been conducted in classroom, workplace and laboratory environments and have included subjects ranging in age from children to older adults.18–21 It should be noted that these principles – as well as the purpose of this paper – focus on short multimedia animations, which represent only one type of instructional tool that may be implemented in an entire curriculum. Brief definitions of these eight core principles are summarised in the first two columns of Table 1, and each is discussed in more detail below.
Table 1. Evidence-based multimedia learning principles and their prevalence in medical animations (n = 430 unless otherwise noted)
|Learning principle||Definition||Animations exhibiting principle, %||Recommendations for animation selection and design|
|Managing essential processing|
| Pre-training principle||Relevant information is presented before the animation||7.7||Provide a glossary of key terms that will be used in the animation|
| Modality principle||Words accompanying an animation are presented aurally instead of visually||17.4||Present spoken text to augment visual content|
|Minimising extraneous processing|
| Coherence principle||Animation contains only educationally relevant pictorial and verbal information||67.2||Eliminate background music, unrelated or unnecessarily flashy graphics, even if they appear interesting|
| Redundancy principle||On-screen text does not duplicate narration||45.6||Rely on narration to communicate verbal information If on-screen text must be used, present as labels rather than sentences|
| Signalling principle||Cues prompt learners to the organisation of essential material||18.9||Prior to the animation, provide an outline of the content If the animation describes steps, list them all first before repeating and elaborating on each one|
| Temporal contiguity principle||Visual elements are synchronised with corresponding narration||76.5*||Synchronise the timing of the animation with corresponding words in the narration|
| Spatial contiguity principle||Labels are placed close to visual elements||92.4†||Place labels on or next to associated images|
|Facilitating generative processing|
| Interactivity principle||Learners control the order, pace and other interactive elements of the animation||61.2‡||Allow learners to pause, navigate through different segments of the animation, and manipulate parameters (e.g. rotate body part, zoom in/out)|
To manage essential processing, the pre-training principle states that key terms should be defined prior to the main lesson content. By providing key terms before the main lesson, learners experience less intrinsic load during the lesson because they are focusing only on lesson content rather than on content plus vocabulary. Thus, learners have an increased ability to efficiently construct schemas and mental models during that time.19,22
Another principle for the management of essential processing is the modality principle, which suggests that words should be presented aurally instead of visually to make the most efficient use of both verbal and visual processing channels.9,23,24 The rationale for this principle rests in dual coding theory: when learning, students can process information in both visual and verbal channels simultaneously. If the learner uses his or her visual channel to process any images or animations, presenting on-screen text to convey verbal information merely divides the learner’s visual attention and reduces the efficacy of the lesson.25 Even though visual verbal information (i.e. on-screen text) is eventually processed in the verbal channel,9,26 visual channel resources are required to initially identify and ‘send’ the information to the verbal channel. By presenting verbal information aurally, the learner can eliminate these extra steps and demands on the visual channel, leading to an efficient use of resources, and thereby optimising the learner’s cognitive capacity.
There is some debate on the exact cognitive mechanisms responsible for the modality effect, as well as the conditions under which it is observed. For example, a recent meta-analysis of studies investigating the modality effect defined two separate modality effects, of which one is for simple verbal items and one is for multimedia items.26 Although this debate is theoretically interesting, we feel that an in-depth discussion on working memory processes and models is beyond the scope of this paper. Regardless of the mechanisms at work, the modality effect has been found repeatedly using the type of materials we reviewed (i.e. short, animated scientific explanations) and we believe that, for practical purposes, the empirical outcomes are more important. For example, the modality effect occurs most noticeably with short (i.e. < 10 minutes) and computer-paced lessons; when learners can control the pace of the lesson, intrinsic load may be diminished, lessening the impact of the text’s modality on learning outcomes.26,27
Principles that can reduce extraneous processing, and thus alleviate extraneous load, are the coherence principle, the redundancy principle, the signalling principle, and the temporal and spatial contiguity principles.8,16 The coherence principle states that unnecessary verbal or visual information should be eliminated because it disrupts schema formation and induces the learner to focus on the irrelevant information at the expense of the key information.28,29 Although it has been shown that the learner’s interest in the overall topic may help recall,30–32 there is substantial evidence to suggest that when that ‘interesting’ information is irrelevant, it impairs the learning of key information.25,29,33
Also intended as a guideline for reducing extraneous processing, the redundancy principle warns that presenting the same verbal information simultaneously in both aural and visual modalities overloads learners’ cognitive capacity because they expend unnecessary effort to process and reconcile both sources of verbal information; thus, narration should not be replicated with identical on-screen text.25,34
The signalling principle suggests that essential material should be highlighted through the use of headings and clear structural indicators, which are cues that help learners focus their attention on only relevant processes rather than using mental resources to attempt to independently discover the structure of a lesson.
The temporal contiguity principle states that narration should coincide with the appearance of relevant visual elements.35,36 The spatial contiguity principle suggests that annotations or labels should appear next to corresponding graphics.37 Adherence to these principles helps learners to reduce the unnecessary mental processing involved in trying to match segments of information that are far apart in time or space, and thus leaves more cognitive resources available for generative processing.
One principle that facilitates generative processing is the interactivity principle, which states that learners should have control over what occurs next on the screen.8,38,39 An interactive environment helps learners engage in the material and generate coherent mental models to facilitate understanding.27 As Table 2 shows, there are many different ways for learners to interact with their environment. For example, learners may be able to control when and where labels appear on screen (Fig. 1a), select part of the image to simultaneously view a global and focused perspective of anatomy (Fig. 1b), rotate an image for a more complete view, or manipulate the transparency or visible layers of an image (Fig. 2). Interactivity, almost by definition, also means that the lesson will be learner-paced, which allows the learning situation to be tailored for each individual. As noted previously, self-paced learning can minimise the negative effects of other adverse learning conditions (e.g. presenting visual verbal instead of aural verbal information)26,27 and is therefore a highly important component of instructional animations.
Table 2. Interactivity elements in reviewed animations (n = 430)
|Interactivity principles||Total animations, %||Breakdown of total, %||Link to example (further instructions or time observed in parentheses)|
|Computer-driven||Learner-driven||Computer- and learner-driven|
| With overall on/off feature||40.9||1.4||39.5||0|| http://getbodysmart.com/ap/muscularsystem/legmuscles/rectusfemoris/tutorial.html |
| Arrows/pin-point||65.3||24.4||25.3||15.6|| http://getbodysmart.com/ap/nervoussystem/supportcells/satellitecells/tutorial.html |
| Individual labels*||81.1||36.0||19.5||25.6|| http://www.argosymedical.com/Skin/samples/animations/The%20Skin%20Healthination/index.html |
|Progression of animations||100.0||56.7||4.9||38.4|| http://www.understandspinesurgery.com/Animations (click Spine Conditions, then Degenerative Disc Disease)|
|Rotation of animations†||59.3||31.6||5.6||22.1|| http://www.bmc.med.utoronto.ca/anatomia/intro.swf (click Larynx, then Structure & Function)|
|Transformation of visual elements¶||31.4||29.3||0.5||1.6|| http://www.bmc.med.utoronto.ca/anatomia/intro.swf (click Orbit, then Digital Dissection)|
|Display layers of anatomical regions|
| Transparency (see through)†||69.3||66.0||1.2||2.1|| http://www.hybridmedicalanimation.com/work/animation/hybrid-interactive-heart/ |
| Peel-back/Cut-Away‡||62.8||57.9||2.8||2.1|| http://getbodysmart.com/ap/muscularsystem/wristhanddigits/extensordigitorum/tutorial.html |
|Speed control||24.5||3.7||19.1||0.7|| http://www.bmc.med.utoronto.ca/anatomia/intro.swf (click Larynx, then Structure & Function)|
| With on/off feature||19.8||1.2||18.6||0|| http://catalog.nucleusinc.com/display_interactive.php?movie=http://hamlet.particleweb.com/flvs/nucleus_remix/nucleusPlayer_sequel.swf&name=ProgressionofAtherosclerosis&title=Progression%20of%20Atherosclerosis&width=720&height=500&bgcolor=ffffff |
| With colour||73.5||63.7||8.4||1.4|| http://www.argosymedical.com/Nervous/samples/animations/Serotonin%20Pathways/index.html (0:30)|
| Outline||17.9||15.1||1.9||0.9|| http://www.understandspinesurgery.com/Animations (Spine Procedures, then TLIF; Step 1)|
| Drag and drop||7.6||0.2||7.4||0|| http://www.bmc.med.utoronto.ca/anatomia/intro.swf (click Orbit, then Structure & Function, then Eye Movements)|
|Transition between global view and detailed view||80.2||74.7||4.9||0.7|| http://getbodysmart.com/ap/circulatorysystem/blood/rbcs/functions/tutorial.html |
|Shrink/expand||42.1||34.4||3.5||4.2|| http://getbodysmart.com/ap/muscletissue/contraction/couplingintro/tutorial.html (click right arrows, then ‘contraction’)|
|Simultaneous display of global view and focused view§||25.7||22.6||2.6||0.5|| http://getbodysmart.com/ap/circulatorysystem/blood/rbcs/functions/tutorial.html (click hemoglobin)|
|Direct manipulation of animations by entering parameters||1.9||0.5||1.4||0|| http://getbodysmart.com/ap/muscularsystem/wristhanddigits/extensordigitorum/tutorial.html |
|Fly-through||34.2||33.5||0.5||0.2|| http://www.argosymedical.com/Other/samples/animations/Process%20of%20Hearing/index.html (0:10)|
Figure 1. Blood pressure, Blausen Medical. (a) Users click on indicated dots to display labels. (b) Picture-within-picture feature for comparing global and detailed views. (Image courtesy of Blausen Medical Communications, Houston, TX, USA. Animations also available as mobile apps)
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Figure 2. Anatomia, University of Toronto. The figure highlights (a) learning objectives, (b) teaching points, and two user-driven features for (c) rotating the portrayed animation and (d) controlling the transparency layers for viewing inner structures. (Image courtesy of Jodie Jenkinson. Copyright: Division of Anatomy, Faculty of Medicine, University of Toronto, Toronto, ON, Canada)
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Although CTML has guided research into the educational effectiveness of animations in various contexts and has even been specifically suggested as a basis for developing medical animations,16 few studies have examined existing animations using multimedia learning principles as a lens for critical review. We applied the eight principles discussed here to our assessment of medical animations. Because the body of medical animations is large and their use in educational settings is widespread, we restricted our review to those animations that were publicly accessible to educators and students. Although there are many sources of paid-for animations that may provide a product that is somewhat different from free animations, we believe it is more likely that educators and students would seek free sources of information first. In addition, many of the free animations we reviewed were samples from companies that produce paid-for animations and thus it is likely that they present examples representative of products that are sold commercially. We believe our review of animations will help inform educators of the possible limitations of existing animations, with the ultimate goal of improving the quality of animation design in medical education. Therefore, increasing educators’ awareness of key instructional design principles that guide animation design may result in a more critical appraisal and selection of appropriate animations for meeting instructional needs.