Abstract

This presentation will introduce the basic design concepts used in a newly developed interactive dissection simulator computer program. This educational software was developed on the Macintosh computer using HyperCard. The program graphically simulates the dissection of an animal, which in this specific presentation is a bottlenose dolphin (Tursiops truncatus). The methodology used may be applied as a template to simulate the dissection of any animal (given the appropriate digitized artwork). The program allows easy expansion to allow a high degree of anatomical detail. It may be customized to present information at the required educational level, from K-college. To implement this program, digitized artwork is linked together in such a way as to present the user with simulated 3D views of various biological objects. Various zoom and fade special effects are utilized to simulate the dissection process. Animated sequences are used to illustrate certain biological processes and are accessible during the dissection. The program may be run in reverse to "build a dolphin" rather than dissect one, which is a preferable metaphor for young children. This program may be a viable and cost effective supplement, or in some cases even alternative to actual animal specimen dissection in schools. It gives the student a chance to investigate the anatomy of an animal which would normally be unavailable for dissection.

Purpose

The goal of this paper is to present the methods and techniques used to implement the dissection simulator. I will not focus on information the simulator presents, it is assumed the audience is already familiar with basic mammalian anatomy. Rather, I will concentrate on how the program is constructed. This software is well thought out and structured, following the generally accepted guidelines used in the field of computer aided instruction (CAI), unlike other "anatomy" software of this type which simply present an assortment of information in textbook fashion. It is beyond the scope of this paper to elaborate on all aspects of CAI, which has become a field unto itself, but some of the most important factors will be reviewed.

The Need

A dissection simulator could be a useful educational tool, as well as an entertaining game. For this reason the program was designed with flexibility in mind. Different versions of this program may be tailored for different user audiences. A very detailed version would be useful in the classroom for advanced students, or a simplified version for children could be used to teach basic anatomy, adaptations, and other interesting facts about the animal. In today's world of animal rights activism, a dissection simulator would seem a welcome tool in the classroom. In fact other alternatives to animal dissection are currently in use, such as:

 Plastic and Soft-sculpture teaching models.

 Modeling clay (student builds model given printed instructions).

 Books using anatomical overlay graphics.

 Anatomical overhead transparencies.

The CAI simulator is simply another alternative to animal dissections. It should be emphasized; however, that in many cases simulation is not a replacement for actual dissections. The "hands-on" approach will always be required in some school curricula. In these cases, the simulator may be used as a pre-dissection orientation tool.

CAI has some advantages over the other simulation methodologies listed above:

 Can teach dynamic physiological processes using animation and sound.

 Can provide interactive feedback - generally less teacher supervision required.

 More information than simple anatomy provided as that provided with physical models, has advantage of book but with extra capabilities.

 May be custom tailored to the audience by user or teacher.

 Can measure user behavior and progress automatically.

 User enthusiasm, attraction to computers; simulators "game-like" quality a motivator, especially in younger children.

Another main advantage of CAI is in the simulation of dissections which would be either too costly, or even impossible to perform in the classroom. Whales and elephants are good examples, but even bacteria or virus dissection simulators are possible. Additionally, simulation of dissection by any method is a safer alternative for grade school children, who could be cut by the sharp instruments.

The major drawback to this program (and any CAI for that matter) is that the proper computer hardware must be available to the student or home user. However, today the personal computer is very popular and will certainly become more widespread in the future. As with almost all educational techniques, the student must be motivated to learn for the simulator to be an effective teaching tool. This is primarily a function of the student's interest in animal anatomy.

Materials

The Macintosh

The Macintosh computer was selected as the development platform for this project since it includes the most important features required to implement CAI. It is a relatively low cost machine considering the high level of integration of functionality required by this project, specifically graphics, high resolution on-screen text (bold, italic, underline and high definition large size fonts), built in sound playback, and extensive system software support for user interface functions such as the mouse. It also includes, free with the machine, the HyperCard application program used to implement this program.

HyperCard

To quote Bill Atkinson, the creator of HyperCard: "HyperCard is an authoring tool and an information organizer."^l To be more specific, HyperCard uses a "stack of cards" metaphor to present and organize information. A stack is a collection of related cards, where the user interacts with one card at a time which is being displayed on the screen. Each card may contain graphics, buttons, text fields and other items the user may interact with. A button may be used to jump to another card in a stack when the user selects it, causing a jump to another card. This is known as a link. The appearance of the button on the screen is known as an icon.

Studio/1

This software is an elaborate but low cost graphics and animation application. It includes HyperCard compatible software to allow animated graphics produced with Studio/l to be played back from within HyperCard.

Other multimedia authoring software is available for the Macintosh, as well as the IBM PC; however licensing fees may be in the thousands of dollars. This program was developed for the minimum amount of equipment. It will run on any Macintosh currently being manufactured without any extra hardware or software.

Methods

Navigation

In this context, navigation refers to mapping of cards in a stack (e.g., how links are placed) which affect how the user can jump from card to card in order to access information. Simple and consistent navigation in the stack is important. Poorly structured navigation can cause severe user frustration and distract from the information being presented.

Structure

There are three very basic structures for linking cards: matrix, linear, and hierarchical (Figure 1). The matrix structure is generally not recommended 2 for any application. It may be very confusing, and the user frequently gets "lost" in the program. The hierarchical approach addresses this problem, it is very easy for the user to backtrack to the top of the structure. However, it is very difficult for the user to know if all cards were seen, so some information may be missed. The linear structure addresses this problem best; all cards will be seen by the user if the program is run beginning to end. This simulator is structured with a combination of both the hierarchical and linear structures. This results in a coherent and very user friendly environment.

Figure 1.

User Interface

The primary user interface used in this software is a very simple 'point and click" metaphor. This is where the user moves a pointer (cursor) on the screen using some device (a mouse, touch screen, etc.) and presses some on-screen button to perform an action. This is generally considered far better than typing commands on a keyboard to perform the same action. In fact, this simulator software does not even require a keyboard to operate. This facilitates use of the software in a zoological or museum setting with a touch screen.

More sophisticated user interfaces available in HyperCard, such as pull-down or pop-up menus are not used. I have found that some people (especially small children) have difficulty interacting with these interface objects. This software is designed so that a minimal amount of time is required for the user to learn how to operate the computer interface.

Implementation

Two teaching techniques are the primary ones used in this program, the simulation and the tutorial. Other techniques, such as drills, role-playing and practice sessions are not used. There are two broad categories of simulator types:³

1.  To teach principles or complex concepts

2.  To teach processes and skills

A good example of the second category is an aircraft flight simulator. This software falls under the first category. The problem is that it is difficult to learn from a simulation only.⁴ Therefore, tutorials are also used in order to teach more difficult concepts.

The dissection process itself is simulated in a linear fashion with progressive states of the process represented graphically, very similar to that done with overlay charts prevalent in anatomy texts. Special fade in and out effects add to the realism of dissection. This linear structure is referred to as the main dissection sequence (MDS).

To progress through the MDS, the user simply clicks on buttons that indicate dissection. Each step is reversible (e.g., the user can "build" the animal also). Each card in the MDS contains a graphic of the animal at a given state of dissection. A highly simplified example MDS is shown in Figure 2, where each box shown represents a card with the graphic object on it (what is shown on the computer screen). Note that there are two cards for each state in the dissection. This is a feature implemented to allow user controlled reduction of screen clutter. Each state in the dissection process actually has two cards, one with a picture of the animal only, and another with all parts of interest labeled. User selection of a "show info" option will cause all labels to be shown, and "hide info" will cause labels to disappear. This is referred to as the show and hide modes.

Branching from the MDS are individual tutorials for various organs, or physiological aspects of an organ. The tutorial is a good technique in CAI for the teaching of factual material.⁵ These form a hierarchical or another linear sequence branching from the MDS in which the user may gain access to more information on specific anatomical parts. The desired tutorial is selected by the user with a simple point and click on the object of interest. This is accomplished with invisible buttons overlaying the organs or other anatomical parts currently being displayed. Operation of this program is therefore made very intuitive. To dissect the animal, simply point and click the on-screen button labeled "dissect"; to get more information on the animal's heart, simply click on the picture of the heart, etc. This is a nice feature since it keeps the screen uncluttered, but has inherent problems. Since buttons are invisible, the user must "hunt" for the buttons, and may miss some tutorials. To address this issue, when the user selects show mode, all anatomical parts are labeled, and all parts that have tutorials associated with them are highlighted. In this case, the hidden buttons are still operational, but the labels themselves become visible buttons which the user may select to access the tutorial (this technique is known as hypertext).

A tutorial may in turn allow branching to another tutorial, but generally no more than two levels of hierarchy are allowed in order to simplify the structure as much as possible for the user. All tutorials must return to the MDS in the same mode as when it was started, or a confusing matrix structure would result. Return to the MDS is made simple as possible, the user simply clicks one button. All main navigational buttons of this type are found at the bottom of the screen at locations consistent throughout the program. Graphics used for each button icon are also made to be consistent whenever possible. The MDS may be thought of as a very elaborate "main menu" for the user to select the various tutorials. A tutorial itself may or may not also have show and hide modes. Program mode is retained when a tutorial is entered. If the mode is changed in the tutorial, it is retained upon MDS return.

The card structure of the tutorials may be diverse, as shown in Figure 2. Some tutorials are very simple (A,B). Others may be more complex, such as a sequence to simulate the 3D rotation of an object (C). A tutorial may even jump to another stack (D), but extreme caution must be exercised to assure the program returns properly. There may be multiple tutorials available from each state in the MDS (E,F,G). Tutorials may execute animations in a variety of ways. The tutorial may consist of an introductory card, and a sequence of cards with frame by frame animated graphics. HyperCard may then automatically step rapidly through this sequence ("show all cards" command) thereby creating a cartoon-like animation. Far more elaborate animations may be created with the Studio/l program, and played back from a disc file by HyperCard. Near real-time animations and digitized video may be reproduced in this manner.

Given this structure, it can be seen that to increase the detail of the dissection process, it is only necessary to add more cards with the appropriate graphics into the MDS. Adding more branches or more cards to the tutorials may be performed to broaden the scope of simulator.

On-line help is available to the user from the MDS, as well as the introductory screen presented before the dissection is started. This is to assist the user in recognition and use of the various program features and interface functions.

An index is available that allows access to all tutorials. This is a useful feature if a user has already run the simulator and wishes to access specific tutorial(s). Access to the index may be restricted; however, by the teacher. This will encourage more "exploration" on the part of the student, which is a useful teaching technique in CAI.6 A "smart" index (or map) of the program may be implemented which assures the user has accessed all tutorials. Every tutorial the student has missed in the current session would be highlighted.

Figure 2. Main dissection sequence - simplified map

Possible Future Enhancements

Inclusion of live digital videos of actual necropsies to increase realism using the vast storage capabilities of compact disc-interactive (CD/1) technology.⁷

Color photographs or video frames of anatomical parts with graphic/text overlays.

User testing and evaluation of educational effectiveness of this software, identify and improve potential weak spots. Automatic behavior and learning measurement and tracking with on-line testing and evaluation.

This simulator may be used with large groups using an LCD overhead projector device.

Company Addresses

HyperCard and Macintosh are trademarks by: Studio/l is copyright by: Apple Computer, Inc. Electronic Arts 20525 Mariani Avenue 1820 Gateway Drive Cupertino, CA 95014 San Mateo, CA. 94404-2499 - (408) 996-1 01 0 (800) 245-4525.

References

1.  Danny Goodman, The Complete HygerCard Handbook, (Bantam Books, 1987), p. xxi.

2.  Apple Computer, Inc., HyperCard Stack Design Guidelines, (Addison-Wesley, 1989), p.28.

3.  Esther R. Steinberg, Teaching Computers to Teach, (Lawrence Erlbaum Associates Inc, 1984), p.1 58.

4.  A.J. Romiszowski, Developing Auto-Instructional Materials, (Nichols Publishing Co., 1986), p.309.

5.  Diane W. Billings, Computer Assisted Instruction for Health Professionals, Appleton-CenturyCrofts, 1 986.

6.  Albert E. Hickey, Ed., Instructional Strategies Appropriate- to Computer-Assisted Instruction, Proceedings of a Conference, Office of Naval Research, Washington, D.C., 1968.

7.  Philips International, Inc., Compact Disc-Interactive, A Designer's Overview, McGraw-Hill Book Co., 1988.