Usability and Pedagogical Issues in User Interface Design

©1996 Evelyn Zayas

Usability and Pedagogical Issues in User Interface Design

Introduction

Human computer interaction (HCI) is a broad area of concern in the software engineering discipline. The maturing science of user interface design within the HCI arena touches upon and incorporates concepts from human factors engineering, industrial design, product usability and assessment, cognitive and social psychology, and educational technology. The term "user interface" is defined as the text and imagery presented on the computer screen to the user. It is a discrete and tangible component of a software application that interface designers can map, draw, design, implement, and attach to an existing bundle of computer system functionalities (Laurel, 1990a).

The purpose of this paper is to provide background information about software user interfaces, its design and development, and the interface design issues of usability and pedagogical impacts. There are inevitably millions of user interfaces being designed each year, considering all of the commercial, shareware and freeware software available and under development on a myriad of platforms. Making usable, intuitive user interfaces is crucial, for it could well be that user interfaces may be the pivotal factor in the integration of the computer into the functionality of the everyday tasks and situations for which the proponents of technology have promised productivity and creative, collaborative learning environments in the home, workplace, and school.

The User Interface

In general, the user interface describes the "look and feel" of a computer, how the human communicates with the computer, and the interaction between the two. Jean-Louis Gassee, former president of Apple Products, describe the interface as the "cognitive locus of human-computer interaction" (Gassee, 1990). Norman likens the successful user interface to a doorknob -- people don't think of the doorknob as the interface to the door, they subconsciously use it to go in and out of a door. He believes that the interface works best when it is so seamlessly integrated with the task to be performed that the user interface disappears from consciousness (Norman, 1990). A person's task, in this analogy, is to walk through the door, and the doorknob is the interaction, the user interface, between that person and the door. Norman feels that the interface designer should be asking the question, "what tools should be provided for the task?", instead of the traditional "how should we design the interface?"

Mountford (1990) believes that we are only just beginning to conceive of computers as extensions of our functional everyday lives. As such, the industrial design principle of "form follows function" applies directly to user interface design. Industrial design is the process of producing useful, usable, and desirable products. Similar to industrial design in many respects, interaction design is the process of producing useful, useable, and desirable software products. The user interface provides the interaction between the computer and the software product functionality. Weed (1996) feels that the rise of interaction design as a formal discipline in the software engineering industry is imminent.

From the user's perspective, the user interface is the totality of the software product. It doesn't matter what is going on 'under the hood' of the computer, it is the presentation of the information on the screen and its engaging qualities of interaction that separate the 'good' user interfaces from the 'not so good'. Greenberg (1996) feels that many programmers, especially those working in small firms producing in-house software, are sadly unprepared for the job of designing good interfaces that would hold up under rigorous usability testing.

The History of the User Interface

The personal computer evolution has chronologically produced basically three interface techniques: command line [prompts], menu systems, and graphical user interfaces. The earliest of the general purpose desktop computers, i.e. IBM PC-XT, provided the operating system as its overall user interface. This command line style interface allowed users to directly execute software programs and operating system commands to accomplish a task at hand. Unless one knew the 'language' of the computer and its exact syntax requirement, communicating with the computer in this manner was difficult and unpredictable at best. Not very user friendly, most would say. The second general category of user interfaces, text-based menu systems, were an improvement in that the menus could provide an indication and abstraction of the functionalities available to the user at any particular time. Menu systems typically consist of functionally or logically grouped interaction points from which the user can select from a finite number of choices. Menu systems have a hierarchical structure, the root of the hierarchy traditionally called the 'main menu' or the 'home page'. Menu systems can become very complex, creating a web of computer screens that the user must traverse within the course of the task at hand. The third category of interface, the graphical user interface (GUI), revolutionized how human and computers interact. 'Point-n-click' technology unburdened the user of the primarily keystroke interaction with the computer. Today, graphical buttons, windows, animation, navigational links, menus, color, text boxes, sound, the mouse, stylus and touchscreen are just a few of the components in the interface designer's "bag of tricks" to produce an interactive environment between the user and the computer via the user interface.

Along with the graphical user interface came the use of metaphors. A metaphor is an invisible web of terms and associations that underlies the way humans speak and think about an object (Erickson, 1990). The use of metaphors within the graphical user interface attempt to function as natural, intuitive models, allowing the user to transfer his knowledge of familiar, concrete objects, and experiences to give structure to more abstract concepts within and about the user interface. Examples of metaphors are the desktop, the file cabinet and the trashcan. Metaphors are powerful verbal and semantic tools for conveying both superficial and deep similarities between familiar and novel situations (Mountford, 1990). However, the use of a metaphor may constrain the functionality of the application for which it represents, or in some cases, misrepresent the functionality. A classic example of this is the Apple trash can, which executes the operations of 'delete the file' and 'eject the diskette for safekeeping', a contradiction in terms for the concepts of 'delete' and 'save'. Nelson (Nelson, 1996) feels that the metaphor becomes a dead weight, for once the metaphor is instituted, every related function has to become part of it.

Laurel contends that "computational tools and applications can be said to have predispositions to behave in certain ways on both functional and stylistic levels" (Laurel, 1990b), basically meaning that the user interface should consistently act and look the same to the user. This allows the user to become familiar and comfortable in this situated learning environment. This translates into the requirement for a consistent, reliable interface from which the user is spared unexpected or irrational response or feedback. Tognazzini (1990) warns that the interface designer can change the look and feel of [the interface] as long as he honors the user's previously learned interpretations and subconscious behaviors. Otherwise, the user's learned response to the interface could be inappropriate, causing unnecessary confusion and frustration to the user, diminishing the usability of the software.

User Interface Design

The user interface designer is a system designer. The interface designer must not only understand how the user interacts with the computer during a particular task, but also how the computer fits into the scheme of the user's total job or environment (the system). Ideally, the interface designer works with a software development team consisting of a programmer, a graphic designer, and a subject matter expert. For an educational software application, an instructional designer should also contribute to the interface and software product design.

The user audience to which the software product will ultimately meet may be quite diverse in terms of computer experience, subject matter knowledge, and cultural outlook and bias. The user interface may have to be the proverbial "all things to all people", carefully balanced to not intimidate the novice as well as not frustrate those who may be more experienced or knowledgeable.

Greenberg (1996) believes that usability engineering is at the heart of the successful user interface design process. At the University of Calgary, he developed and offers an undergraduate course in HCI, presented as a usability engineering process that integrates the design, implementation, and evaluation of interfaces. The major goal of the course is to provide the students with sufficient skills to design, implement and evaluate usable interfaces in real life work environments, in light of possible budget, time, and managerial constraints.

For large-scale software systems, the user interface component may undergo its own development cycle, perhaps following the traditional "waterfall" model of software development that includes the requirements and specification writing, designing, coding, testing, implementation, and evaluation phases. In this model, usability testing and evaluation is done during the latter part of software development process. The Windows 95 user interface design team determined that this model of software development was inappropriate, due to broad design goals and an aggressive schedule of approximately 18 months to design and code the user interface (Sullivan, 1996). Their two main design goals were to make Windows easier to learn for people just getting started with computers and the Windows environment, and to make Windows easier to use for both typical and advanced Windows 3.1 users. They instituted an iterative design approach, divided into three major phases: exploration, rapid prototyping, and fine tuning. In the exploration phase, they experimented with different preliminary designs and gathered initial user data. Prototypes of the most promising designs were coded or mocked up and presented to the sample users for evaluation and feedback. The purpose of the fine tuning phase was to holistically test the Windows 95 interface with a sample of users of differing experience levels, to collect usability data for future product planners and to locate possible technical support hotspots.

Bruce Tognazzini was been quoted to say that by creating a product that wastes a half hour of time for each of 4 million users, you waste 900 work-years of human productivity. That works out to about 12 complete lives (Joiner, 1995). Usability testing, even on a small scale, can improve the intuitiveness and effectiveness of the user interface dramatically. Discount usability engineering, devised by Jakob Nielsen of SunSoft (Nielsen, 1995), is a deliberately informal methodology that relies less on statistics and more on the interface designer's ability to observe users and interpret results. Nielsen and one other engineer, given four months to develop an internal World Wide Web information system for Sun Microsystems, conducted four usability tests over a two-week period, iteratively refining their design. In the first test users sorted cards, each containing a software command name, into groups. The resultant groups helped to define the menus and menu choices of the interface, because the card groups served to illustrate the users' mental models of the information space. The second usability study involved a test to determine if icons, designed for each high-level card group, conveyed the intended meaning to the users. In the third study, users matched the cards to the icons, to determine if the users correctly associated the concepts expressed on the cards with the concepts represented by the graphical icon. In the last usability study, the walkthroughs of the 'web pages', the users were asked to point to each icon and describe the types of information they would expect to receive back. Nielson feels that even though this usability testing is 'cheap and quick', it is an invaluable tool for designing effective, intuitive user interfaces.

Sellen and Nicol (1990), in the first step in designing an interface, conducted a series of studies to determine what kinds of questions users typically had when interfacing with unfamiliar Macintosh software with no on-line help available. The resultant five categories of questions were: goal-oriented, descriptive, procedural, interpretive, and navigational. The design implications were that the kind of information delivered back to the user should be different depending on the question asked, and the way in which information is accessed and presented should depend on the question asked. An answer provided in context to a question reduces the user's cognitive overhead to interpret and assimilate this new information. Cognitive overhead is the additional effort or concentration required to maintain multiple 'trains of thought'.

Thuring (1995) theorizes that the primary design issue for creating hypertext documents is an interface that supports the construction of a mental model of the hypertext in the mind of the reader. Hypertext, the presentation of information in a non-linear format, lessens the control the designer has over the logical sequencing, contextualization, and presentation of the subject matter to the user. Subgoals to this endeavor are to increase the coherence of a hypertext while reducing the reader's cognitive overhead. Since the user has more control over what information to access, the risk of incomprehension by the user is increased on how specific information relates to other information, or to the context of the hypertext document as a whole. An important factor in the design of hypertext is its navigational tools and cues -- getting lost in cyberspace is a common phenomena that increases cognitive overhead as the user traverses a maze of information for which the 'roadmap' is vague.

The design of a multimedia presentation and interaction faces similar problems as the hypertext design. However, the potentially increased educational value of multimedia stems from the designer's ability to include a plethora of visual, auditory, and tacit devices and mechanisms within the interface. This translates into the ability to provide subject matter and interaction in a variety of ways, perhaps geared towards different learning styles, mentalities or physical disabilities.

Pedagogical Issues of the User Interface

There is overwhelming evidence that students learn best when they engage in activities that are authentic, motivating, and pertinent to their needs and desires. Human-computer interaction, from a pedagogical standpoint, can address these characteristics, as well as to present the subject matter at hand.

The traditional methodology of the expository process of instruction - presenting information, guiding the student, practicing by the student, and assessing student learning - is typically found in computer-based instruction (CBI) software. CBI is primarily built upon behaviorism fundamentals. Alessi and Trollip (1991) believe that the areas of cognitive theory most important to CBI design are those relating to perception and attention, memory, comprehension, active learning, motivation, locus of control, transfer of learning, and individual differences.

The user interface of an educational software product can exhibit 'scaffolding', which enables the user to start the learning activity with his or her current understanding, but then challenge and channel the user to develop the next level of understanding and performance (Soloway & Pryer, 1996). Researchers at the University of Michigan have developed a framework for learner-centered design (LCD) that is theoretically motivated by sociocultural and constructivist theories of learning. These two theoretical perspectives are consistent with each other, they just emphasize different themes. Constructivism speaks to the individual's cognition, while socioculturism speaks to the contributions of the surroundings to that cognition. The central claim of LCD is that software can embody learning supports through scaffolding that can address the learner's growth, diversity, and motivation (Soloway et al, 1996).

Aside from constructing interfaces that support "doing tasks", designers can construct interfaces that support "learning with doing tasks" (Soloway & Pryor, 1996). The interface, a tool to assist the user in accomplishing a specific task, could simulate the environment in which that specific task is called for to provide an authentic context, enhancing the possibility of future knowledge transfer by the user. For example, an electronic spreadsheet can provide the mathematical mechanics for statistical forecasting. To incorporate this "learning while doing" strategy, the interface could present the typical or traditional concepts and processes of statistical forecasting along with the mathematical mechanisms. Driscoll (1994) describes learning as a lifelong activity that occurs intentionally in formal instructional settings and incidentally through experience. The user can vicariously gain experience from the simulation of an environment through an authentic user interface.

Collaborative Learning

Leary (1990) believes the personal computer interface is based on the way individual people deal with ideas and information, and that the computer screen as a "portal to other minds" calls for a interpersonal computer interface, based on how people communicate with one another.

In collaborative learning, distributed expertise and multiple perspectives enable learners to accomplish tasks and develop understandings beyond what any could achieve alone. The communication required in collaboration prompts learners to express beliefs in ways that serve to organize what they know and to identify gaps in their understanding (Edelson et al., 1996). In this social learning environment, the problems of work patterns and flow cycles typically surface, elements of interest in the social sciences. Leary acknowledges the findings of cognitive science and its impact on user interfaces design, and advocates the resources of social psychology as well.

The explosive growth of networks within the work and school environments has paved the way for computer-based collaboration software, a new breed of software products: groupware, computer-supported intentional learning environments (CSILE), and computer-supported collaborative work (CSCW) to name a few. Vertelney (1990) believes that the collaborative environment contains technologies from three domains: database, communications, and user interface. The database serves as the shared memory and project archive for the collaborative work, and the communications technology provides for both synchronous and asynchronous communications situations amongst the group members. The user interface provides "the rules, processes, cognitive aids, and packaging necessary to make [the] environment rich but not bewilderingly complex, secure but not unfriendly, robust but not burdensome, and familiar but not invasive". In the same way that the user interface is the interaction enabler for the user and the computer, Leary's "interpersonal computer interface" in the computer-based collaborative environments is the interaction enabler for and between the members of the group.

Conclusion

Within the last 20 years, the user interface has progressed from a cumbersome command line to a multi-modal, metaphorical environment. The design of human-computer interaction through the user interface has been influenced by concepts within industrial design, the cognitive and social sciences, and instructional and collaborative design methodologies. The demand for intuitive, useful and usable user interfaces is great. Two factors within the interface design process are the usability of the software product, and its value as an educational and productivity tool. Several approaches to usability testing were presented in this paper to illustrate different types of design problems, solutions, and outcomes. In Nielsen's words, "some usability testing is so much more than none." Pedagogical issues of interface design presented touched upon cognitive, social, and instructional theories in the student-centered and collaborative learning environments. Today, just the technologies of virtual reality and speech and gesture recognition open up a whole new vision of how humans and computers may interact in the future. The budding science of interaction design has only just begun.

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