D.A. Weaver
Department of Physiology,
University of Melbourne,
Melbourne, Victoria, 3052
D.Weaver@physiology.unimelb.edu.au
T. Petrovic,
Department of Physiology,
University of Melbourne,
Melbourne, Victoria, 3052
T.Petrovic@physiology.unimelb.edu.au
A. Dodds
Multi-media Education Unit,
University of Melbourne,
Melbourne, Victoria, 3052
A.Dodds@meu.unimelb.edu.au
P.J. Harris,
Department of Physiology,
University of Melbourne,
Melbourne, Victoria, 3052
P.Harris@physiology.unimelb.edu.au
L.M. Delbridge,
Department of Physiology,
University of Melbourne,
Melbourne, Victoria, 3052
L.Delbridge@physiology.unimelb.edu.au
R.E. Kemm
Department of Physiology,
University of Melbourne,
Melbourne, Victoria, 3052
R.Kemm@physiology.unimelb.edu.au
Abstract:
We have produced an interactive tutorial that allows students to develop different approaches to solving physiological problems - analysis, synthesis, trial and error, collaboration or accepting instructional presentations. The procedure allows students to develop ìthought experimentsî of a ìwhat if?î nature, a process usual in traditional one-to-one interaction with tutors.
This and subsequent tutorials provide students with opportunities to construct and test their own personalised models of mechanisms underlying physiological processes that account for data gathered in practical classes.
The studentsí task in this tutorial is to construct an acid secreting gastric cell by moving key ion-transporters from a palette onto a cell template as they build and test the operation of their model. Animation and feedback encourage correct decisions, while addressing common misconceptions.
This paper demonstrates an approach to the design of interactive multi-media tutorials which encourages deeper learning practices and which has broad application in other disciplines.
1 Introduction:
Our objective in developing interactive multi-media tutorials is to encourage deeper learning of the subject so that students are able to make active use of such knowledge in future problem solving situations. The constraints of current curricula in professional and scientific courses often make this difficult, since the presentation of information and its assessment tends to reward retention of knowledge by rote learning. However, there are trends towards science and medicine being taught in problem-solving contexts.
This tutorial development is the prototype for a series planned to allow students to construct their own mental models of the operation of physiological mechanisms as a means of solving applied problems. How this is achieved with appropriate consideration of pedagogical design, within a conventional syllabus, has application in other professional and scientific tertiary courses.
1.1 Pedagogical Issues:
Computer-based learning is being introduced apace in traditional tertiary teaching programmes, Cochrane & Ellis [2], driven more by technological change and financial constraints than demand for improved learning practices. It is often simply assumed, without research evidence, that the move from didactic teacher-centred lecturing to self-paced student learning with multi-media tutorials will naturally lead to improved learning outcomes. Many interactive multi-media tutorials are still based on didactic teaching practices, "show-and-tell styleî, coupled to drill-and-practice question sessions that may not encourage deeper learning. Few are of simulation and ìmicroworldî styles that might enable deeper learning practices.
An increasing world-wide drive for self-paced learning, focussing on problem solving in medical curricula, requires an understanding of impacts of new technologies on learning, Laurillard [6]. Many factors affect the impact on students of multi-media experiences: Bowden & Anwyl [1], Jonassen & Reeves [3], Ramsden [8], Ramsden et al [9], Samuleowicz & Bain [15], Trigwell et al [16].
Recently there have been more efforts to evaluate the pedagogical design of multi-media tutorials, Reeves & Harmon [12], but most multi-media evaluation focuses on interface design.
General studies on testing for improved student performance with self-paced learning have proved inconclusive, Reeves[11].
Jonassen and Reeves [3] suggest that multi-media technologies should be used as cognitive tools for learning where students use the medium to actively construct their own knowledge. This critique reinforces several important points inherent in the design philosophy in our current project, that are different from our earlier productions of interactive multi-media. Jonassen and Reeves [3] argue that student learners need to be designers, analysers, interpreters and organisers as they actively acquire and develop their own ideas and represent them to others. Ideally, each learner develops their own unique interpretation of reality, using external resources and reflective thinking, to assemble their knowledge base which shows their comprehension and conceptualisation of this information: i.e. a constructivist approach. The authors indicate that this is preferable to the objectivist approach where students absorb pre-determined presentations of objective knowledge. In our view, the latter approach is a tendency inherent in many computer-based tutorials. Jonassen and Reeves also comment on difficulties students have in transferring knowledge from hypertext based resources into their own knowledge structures, due to the unusual cross-linking of hypertext that is really only accessible by computer. Even when computers are more widely available, we see a need for students to represent knowledge they gain from such programs in a more generally accessible form, on paper, to aid retention of learning experiences.
Reeves and Okey [13] have reviewed the need for alternative assessment of constructivist learning environments, since current practice in many tertiary courses still tests retention of knowledge and is not effective in assessing the other important goals of education; developing a deep understanding of the discipline and the active use of acquired knowledge. The use of ëauthenticí, ëperformanceí and ëportfolioí assessment is discussed as is the need for such alternative assessment to keep pace with the development of constructivist learning environments.
Our multi-media productions have to recognise the need to assess students within present structures. Medical students in ours and other Universities show little interest in computer-based tutorials, unless they see them as relevant to the assessment of their course. We hope that the students will find our tutorials interesting and that they improve their understanding, but we will need to show relevance to assessment by rewarding deeper learning within our examinations system.
1.2 Issues in Physiology:
Successful students in traditional physiology examinations may have good recall of individual mechanisms and facts, but inadequate understanding of the behaviour of integrated physiological systems. The latter is one of the most difficult learning areas for students and teachers, Rosenberg et al [13]. The use, and evaluation of the design and impact on learning outcomes of computer based tutorials is limited in Physiology, Kemm et al [5].
Physiology is traditionally taught with lectures, practical work and tutorials. Students find physiology difficult because there are so many concepts to understand, and rote-learning is not as effective as it might be in other disciplines. In addition, increasing student numbers and financial constraints have meant students in some courses have limited access to tutorials. To address these issues and to maintain the important role of small group tuition in learning, we are extending our current teaching by developing computer based tutorials that encourage and reward deeper learning practices by students. This will allow students increased scope for self-paced learning and provide feedback to them that could otherwise have been presented in one-to-one tutorials. Since our feedback is really individual, it may be better than could be given in our large normal tutorial groups.
To date we have improved studentsí learning experience by making practical work a focus for using information gained from lectures in novel applied contexts. Provision of advanced computer-based recording systems, with on-screen electronic help, has enabled students to perform better experiments, Kemm & Petrovic [4]. However, there is a need to improve their integration of these learning experiences with the rest of the course content. Students do not always appreciate the significance of data they obtain in their practical classes as many students still regard laboratory classes as ëcookbookí exercises and they fail to take opportunities provided for discussion and learning in context with their lecture material.
Our laboratory class activities are structured into three periods:
ï the pre-lab: when the students become familiar with the hypotheses of the experiment, the clinical setting in which it might be relevant, and the physical processes they will perform;
ï the laboratory class: when students participate in practical work and obtain data; and
ï the post-lab: when consolidation of information obtained in the laboratory class occurs through the interpretation of data and when they may extend this knowledge to explain some clinical situations.
There are insufficient human resources to challenge each student through individual discussion, thus integration of practical class information with theoretical material is limited and misconceptions remain unresolved.
2 Overview of Tutorial Development:
2.1 Background:
Our overall approach to development has been to carefully plan the core conceptual components of the tutorial before extensive involvement with computer programming or graphics artistry.
We obtained a CAUT grant, funding 50% salary of a programmer, to develop an innovative solution to provide new and deeper learning experiences for students, as an adjunct to their practical classes.
The first tutorial is in a beta-stage for evaluation with a select group of undergraduate science and graduate students in second semester 1996, prior to its introduction in the second year of the medical and physiotherapy courses in first semester 1997.
This tutorial, and the practical class that it supports (based on Nicol et al [7]), deal with the control of acid secretion by the stomach and possible pathological outcomes of excess acid production. leading to ulcer formation.
2.2 Current Practical Class and the Physiological Problem for Study:
At present, students work in groups of four to six to investigate factors affecting secretion of acid from the stomach, using one of their number as subject.
During the class, they pass a nasogastric tube to extract samples of the stomach secretions in normal subjects and in situations where stomach acid secretion is enhanced or inhibited by drugs and hormones.
Students then analyse the data for their group and pool the results for the class on computer spreadsheets.
At the end of the class, 50-60 students are addressed by a staff member who discusses the results in context with their lecture material. There are very restricted opportunities for staff/student interaction with such a large class and insufficient time to deal with individual studentís problems.
This subject is examined in a variety of ways at the end of semester, using multiple-choice questions, short format answers, or by essays.
3 Development of the Tutorial:
The main stages in development have been
1) identification of the particular difficulties experienced by students,
2) development of a plan for the content of the tutorial to address these problems,
3) prototyping a tutorial structure and operation, addressing appropriate pedagogical and interface design issues,
4) continual formative assessment with students, academics and educational experts,
5) final improvements in operation and aesthetics, the latter with the aid of a graphics artist.
3.1 Identifying Studentsí Problems with Concepts:
The subject of gastric acid secretion was chosen because anecdotal evidence from examination results suggested that some students were unable to deal with problems requiring any additional thinking about the subject and some students also performed poorly in their attempts at rote learning of material.
Our first step in the development of the tutorial was to investigate past performances by students in examinations on this subject, to identify the difficulties and misconceptions held by students.
Detailed spreadsheet analysis was performed on the previous examination: firstly for the presence of all necessary components required in their answers, and secondly for the identification of components that might exhibit deeper, rather than rote learning.
The relevant question on the previous examination required students to place various items on a diagram to indicate their understanding of how various agents interfered with secretion of acid from the stomach.
Approximately 200 studentsí examination papers were studied after the original examiners marking scheme was determined. The initial analysis showed that most students gave reproductions of the original diagrams presented in lectures, including similar locations of the various ion transporters in their representation of an acid-secreting cell. Analysis for the presence of each of the components demonstrated their ability with rote learning, but inappropriate placements and combinations of transporters indicated a lack of conceptual understanding. Many students did not understand the logical requirements for the cell to be able to secrete acid on a continuous basis and be controlled by various applied agents.
The following supplementary investigations assisted in setting the framework and the content that needed emphasis in the tutorial:
ï discussions with the lecturer and reference to synopses and marking schemes for questions on this topic.
ï review of current practical notes with tutors, and revision of notes to include additional measurements that would assist students to development their working models.
ï examination of studentsí practical reports on this experiment.
ï observation of studentsí participation in the practical class.
3.2 General Planning for Our Tutorials:
Students, in their post experiment session, use computers to help them build integrative working models based on theory obtained from lectures and data collected in the previous laboratory classes. They will work in groups of 2-3, to promote discussion of physiology.
They begin at a comparatively rudimentary level and gradually build up a pictorial representation (working model) of the topic from sub-cellular to whole body aspects. The computer program is effectively an expert system that assists studentsí construction and testing of their own mental models by providing tools such as concepts, diagrams, and physiological principles.
Academic staff provide an expert model that is consistent with current knowledge and of appropriate complexity for comparisons with studentsí working models. This model is not a full mathematical simulation, but emphasises the logical operation of its elements and directions of change in appropriate parameters as the model is constructed. Students may find deficiencies in their model, a need to adjust conceptions, suggest modifications in the expert model, or exhibit misunderstandings in common with other students.
Substantive feedback is designed to reinforce correct decisions, with various levels of hints to deal with decisions that are impossible, or plausible but inappropriate. They can be referred to other resources, or have questions posed at various stages to test their reasoning and understanding. These operations and results are logged by the software and are available for later analysis.
Students fit their own data into the model to see if it is consistent with their model. Also, they may predict outcomes based on real events, such as hospital case studies or scientific experiments.
The tutorial is designed to allow students to develop a deeper understanding of physiology by use of their model to solve problems and develop the ability to integrate material from a variety of sources, with ëhands oní practical work, closely mirroring real life situations.
3.3 Design Principles in the Prototype:
Although we have experience in developing previous multi-media tutorials, we carefully reviewed the pedagogical and interface issues for our current design, with the assistance of members of our Centre for the Study of Higher Education (CSHE) and with advice from our reference group for the CAUT project.
In particular, we are keen to encourage constructivist learning practices within the constraints of a statutory medical curriculum that still requires some objectivist techniques in defining the constraints of the knowledge area. We could be considered by Laurillard [6] to be taking a ëguided constructivistí approach], one that puts the learning situation in a real-world context.
Although Reeves [10] developed a scheme to assist in the evaluation
of pedagogical issues in multi-media learning systems, we found
this very useful in planning our tutorial, as well as in formative
evaluation of its progressive development. Fourteen pedagogical
dimensions are summarised in Fig 1 (adapted from Reeves [10] &
Reeves & Harmon [12]) and the general principle is that good
multi-media design aims to be towards the right hand side in each
category. However, consideration of the real constraints of the
teaching environment means that compromises are needed with some
dimensions.
Similarly, we considered appropriate dimensions in the interface and screen design proposed by Reeves & Harmon [12,] particularly those issues pertinent to the complexity of student manipulation of objects on screen for their modelling.
Our main criterion was to adopt a largely constructivist approach, emphasising cognitive processes within a flexible learning framework that could address individual learning skills within our disparate student population.
It should be stressed that the special approach in this tutorial is that it is a logical model of the system, supported by empirical data for the variety of outcomes possible with each studentís own construction. It is not based on an open-ended conventional simulation of the operation of a physiological mechanism.
Animation is used to demonstrate the operation of their model. Supporting quantitative data, based on reasonable assumptions, is provided to compare with their own experimentally obtained data.
There are limited combinations of elements to be manipulated on screen as they progress to a final working model. The matrix of combinations is mapped and appropriate responses to each is decided on their relative physiological importance, or concern about misconceptions that might arise.
Perhaps the most important feature of the tutorials is the power of core animations and their cognitive load. This requires simpler screens than more static multi-media tutorials and enables supporting core information to be presented in stages.
We have chosen to leave the detailed aesthetics of the tutorial
design until the evaluation of the beta operating version of the
tutorial, as we do not wish to be restricted by screen-layout
until all the educational issues and general control and feedback
features had been decided. This includes such matters as the
appearance of a model to hint at its structure/function relationships
and final choices and design of navigation buttons. Final colours,
textures and shapes of objects on screen will be decided in discussion
with graphic artists.
4 Operation of the Tutorial:
In the particular tutorial being presented here, the problem is for the student to understand the physiological mechanisms underlying and controlling the secretion of acid by the stomach. This means they need to understand the sub-cellular processes that are involved in controlling cellular acid secretions.
A demonstration is the most effective way of showing
how a student can construct a working model of a typical acid
secreting cell and the possible interactions generated by the
computer to challenge their decisions and understanding.
This paper can only show snapshots of screens and dialogue boxes to illustrate features of a typical student trail through the tutorial and the challenges they might face. These snapshots are used to illustrate the development process and highlight the following issues:
ï designs that allow students to discover how component processes of the system operate, through the use of animations, movies and images as well as quantitative data
ï planning to cover the spectrum of student construction and testing of their models
ï graphic and textual presentations to encompass different learning styles
4.1 Introductory & Supporting Resources:
Students are able to orient themselves with the relevant
anatomy by viewing a digital video from a gastroscope that shows
its entry into the gastrointestinal system at the oesophagus,
and progressing until the stomach is entered. The regions of
the stomach can be viewed for normal and pathological tissue.
A digital video is also used to show the use of a nasogastric
tube to sample stomach contents.
Other resources include scanning electron micrographs,
e.g. Fig 2 of a gastric pit, the region in which acid secreting
cells of the stomach are located; normal light and electron microscope
views of histological sections of the stomach.
Finally, detailed diagrams show the structural features of a quiescent
and an acid secreting cell. This image is then faded and modified
to become the background for the presentation of a simplified
cell that is then used as a template for the student to construct
their working model on screen.
4.2 Student Construction of a Model:
Students are presented with a template of the cell, with the essential ëhousekeepingí transporters already shown for a cell, and regions representing the blood supply, the extracellular fluids, and the lumen of the stomach in which the acid collects.
Their first task is to use this template to construct a cell model that is able to maintain and control secretion of acid, by appropriate use of molecules and ions from the blood and transport mechanisms in the cell membrane.
They are presented with a palette of key transporters of ions that might be involved in acid secretion and asked to select and place one of them on any appropriate place on the template of a cell and choose an appropriate direction for its operation.
They can then test the operation of the cell with this transporter and observe the animated movement of the ions that will be affected by their choice.
The first screen (Fig. 3) shows the end-point of an animation of the movements of important ions in acid secretion, in this case after a student has chosen to place one ionic transporter in the appropriate part of the membrane, but operating in the wrong direction. They can be given a hint to correct the fault or asked questions that might help them understand their error.
To assist their interpretation of events, students can also ask for feedback about the concentration changes of the ions in the cell and its surrounding. The bar-length in Fig 4. indicates the concentrations compared with normal; the individual values are available by clicking the mouse on any bar.
Concentration bars were always available in the initial trials of the program, but most observers did not notice that they were also animated. To avoid cognitive overload, this feature is now optional after the first animation is seen.
Students continue to place additional transporters and test their operation.
Eventually, either by trial-and error, or through reasoning based on knowledge gained by following less likely paths, students will obtain a final working model. Their screen representation of the model will correspond to an expert model, but will represent their personal choice of location for the transporters (Fig 5. . They can now print a copy of their solution. They may place the transporters in any position on a membrane where they are known to be found from research
At each stage in the development and their testing of a model, they are given feedback or asked questions about the reasons for their choices. This assists them to build their model.
In early trials, novice users did not appreciate the source and
cycling of the various ions during the animations. It was decided
that showing animations together with trails of the ion movements
would produce a cognitive overload, so this screen presentation
is now optional after the model is completed (Figure 6).
4.3 Effects of Drugs and Hormones:
After students complete their model of secretion of acid by a cell, they are then given a range of tasks to test effects of various drugs and hormones on acid production. These aim to challenge their understanding of physiological mechanisms that explain the composition of the stomach which were sampled from their subjects - after using such drugs during their practical class.
These tasks require them to locate the various receptors
on the model cell and test the operations
of the various agents and where they act. Animations show the
additional intracellular mechanisms involved in increased or decreased
acid secretion. Students are quizzed on their choices and their
observations of the critical processes involved.
Figure 7 shows the end of an animation illustrating the effect
of histamine on acid secretion and the various intracellular molecules
involved. This test was performed with the drug Pentagastrin,
binding to its receptor on a nearby cell.
5 Evaluation:
The team met regularly for formative evaluation of the tutorial operation, in terms of the original educational plans, to complete a beta version of the tutorial for testing with others.
Once this was achieved, informal evaluation was undertaken with experts in the field, academic and general staff and current students. This enabled us to develop a selective strategy for the more definitive evaluation using junior teaching staff involved in practical classes; through interviews, questionnaires and the use of audit trails within the software.
The tutorial will then be modified for use in the classes in 1997 and the audit trail optimised to monitor the important areas of interest in the studentís operation of the tutorial.
We plan to add additional material to extend this tutorial, dependent on the evaluation of its use in the first practical classes. This includes allowing better students to incorporate secondary transporters that could be involved in controlling acid secretion and also to deal with examples of disturbed physiology. However, we have to consider the time constraints in a crowded tertiary course in determining the total content of the tutorial.
6 Conclusion:
The concern in all experimentally based disciplines is that graduates must have a grasp of both factual and conceptual information, and be able to take part in experimental, scientific and medical studies. They need to develop deeper learning strategies to be competent in problem solving situations relevant to future practice in their profession.
Our tutorials are intended to assist students to develop an effective analytical approach to problem solving as they construct their own personalised concept maps of mechanisms underlying physiological processes.
Confrontation with real world measurements is important for undergraduate education and provides students with the opportunity to test their knowledge in problem solving. It is important that there is extended time, scheduled outside lecture times, for the students to explore and discuss physiology with their peers. Practical classes can provide an excellent opportunity for a maturing of their understanding of basic mechanisms.
Acknowledgments:
This project has been funded in part by a grant from the Committee for the Advancement of the University Teaching (CAUT).
Valuable advice has been received from Dr. Darren Williams and members of the Biomedical Multi-media Unit and from the Multi-media Education Unit of the University of Melbourne.
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