Causes for disorientation
In the initial analysis of the problem of disorientation, a number of different reasons for disorientation were identified. In summary, these are:
It is essential for the orientation to com-municate orientational information, information that shows the user where she is and gives an overall view of the system. Some of the most central aspects of orientation concerns knowledge of the world -world vision - and knowledge of central reference points in the world. In this thesis we have looked at how to eliminate tunnel vision and provide world vision by visualizing the structure of the system and presenting infor-ma-tion in its context.
Summary of results from the empirical study
Two versions of an experimental hypermedia system have been compared in an empirical study (see chapter 6). The most important observations from this study are that:
Statements made by the subjects support the idea that it is valuable to communicate orientational information. However, communication of orientational information can be done in a variety of ways. More research is needed to explore different techniques. Input from experienced graphical designers is also essential.
Design principles
I belive that much of what is discussed in this study can be applied to design of hypermedia systems. The following is a summary of design principles, related orientation, browsing and navigation in hypermedia systems, which have been concluded from this work.
Provide world vision. Communicate what and how much information is available in the system. Use small maps and other visualizations to give an overall view. Provide something similar in function to a table of contents in a book. Visualize abstract information.
Show the user where she is. Since hypermedia can be abstract and difficult to grasp and allows for quick and varied browsing, it is critical to maintain a sense of 'where one is'. Show the user where she is on, for instance, a miniaturized or ever present map with a location indicator.
Provide a stable frame of reference. Provide a common frame of refer-ence, like a visually stable background picture or an ever present map.
Relate detailed information to its context. Present detailed information in its context, not in isolation. Have visual references to the whole. One method is to show detailed information in a magnified view which is visually related to the basic picture.
Do not fragment information. The user should not have to switch back and forth between different screens when reading information. If information does not fit on one screen, provide a frame of reference common to all infor-mation items, for example an ever present map, or use an interactive picture. Remember that it is much easier to recognize than to recall information.
Visualize clickable areas. Use a consistent graphical style for buttons. If visually explicit buttons clutter the presentation, make it optional to display them. Optionally use the shape of the cursor to provide feedback, or highlight clickable areas when the cursor is inside them. Provide consistent principles for where it is possible to click.
Ideas for further research
When conducting research we continually discover new questions to be answered and new areas to be explored. The following are selected ideas for further research on orientation in hypermedia structures.
Graphical design for dynamic, interactive media. Applying design principles of traditional media to hypermedia is interesting and promising, but there is a strong need to investigate issues raised by the dynamic nature of hyper-media. Lexivisual presentation has been developed for static presentations, and might not be applicable on all levels to, for instance, interactive pictures. It is most important to work on this issue in close cooperation with professional graphical design-ers and animators and develop principles for communication with interactive media.
Visualization of abstract concepts. The solar system is straightforward to show graphically. It is necessary to study how visual techniques for orientation can be applied to topics which do not have a given pictorial representation.
How to show which information is available. Two problems with respect to orientation are to show which and how much information is available, and to show where it is possible to get more information (that is where to click). What is needed is a graphical language for hypermedia, something which has a function similar to, for instance, the visual language of comics. Such a language has been suggested by Evenson & Rheinfrank (1989).
Studies of drama and film. We have studied communication techniques used in printed media only. Other forms of communication, for instance drama, motion pictures, rock videos, and animated cartoons, should be of great interest to hypermedia (Heckel 1984).
New data models for hypermedia tools. The node-link model currently employed by many hypermedia tools, lacks several basic mechanisms desirable for modeling hypermedia structures. I believe that alternative models would be worth investigating. Here an object-oriented model has been suggested. There are, however, additional modeling techniques which might be suitable for hypermedia systems. Examples are frames, semantic networks, inference rules, and other techniques used for knowledge representation.
Non-visual forms of communication. This thesis has been concerned with visual communication only. Sound and tactile feedback would most certainly be a valuable complement to visual communication. Especially for visually disabled people, sound cues and physical maps, for instance in the form of a large input/browsing table, are likely to be useful.
Empirical studies of large hypermedia systems. Finally, but most importantly, research has to be performed on systems in real use. This work has dealt with small examples only. Empirical studies of large, real world systems are necessary to further test the ideas presented here.