Kortum P. (ed.) HCI Beyond the GUI. Design for Haptic, Speech, Olfactory, and Other Nontraditional Interfaces

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Nature of the interface:

Each chapter begins with a description of the fundamental

nature of the interface, including the associated human perceptual capabilities

(psychophysics). While the details of these discussions may seem unimportant

to the practitioner who simply wants to build an interface, an understanding

of pertinent human strengths and limitations, both cognitive and perceptual,

is critical in creating superior interfaces that are operationally robust.

Interface technology:

As with any interface, technology is often the limiting fac-

tor. Some of the interfaces described in this book use very mature technology,

while others are on the cutting edge of the research domain. In either case, a

detailed description of the technologies used and their appropriate implementa-

tions are provided so that the practitioner can specify and construct basic

interfaces.

Current implementations of the interface:

This section describes how and where

the interface is used today. Examples of successful implementations for each

interface are given, as well as examples of failures (where appropriate), which

can be very instructive. Another topic that is included in this section is a discus-

sion of the interface’s application to accessibility. Many of these interfaces are of

special interest because certain implementations provide crucial interfaces for

people with physical or cognitive disabilities. For example, Braille is a low-tech

haptic interface that allows blind users to read. This section briefly discusses

the benefits of using the technology to assist individuals who have physical or

cognitive impairments, and provides examples of special implementations of

the technology for such users. If use of the interface has any special adverse con-

sequences for the disabled population, these are noted as well.

Human factors design of the interface:

This section will tell you, as the human

factors designer, what you should be considering as you embark on the design

or evaluation of a given nontraditional interface. It discusses when to select a

particular interface, the data required to build the interface, and details on what

a human factors professional would need to know in order to specify such an

interface for use.

Techniques involved in testing the interface:

Special interfaces usually require

special testing methodologies. This section describes special testing con-

siderations for the interface, special technology or procedures that might be

required, and methods of data analysis if they are sufficiently different from

standard analysis methods. Even if standard testing measures are used, a

description of these and when they should be applied is included to guide the

practitioner. Special attention is paid to the concept of iterative testing if it is

applicable to the specific interface.

Design guidelines:

For experienced designers, guidelines can appear to be too sim-

plistic and inflexible to be of any practical value. However, for the beginning

designer, they serve as an invaluable way to generate a first-generation design

1 Introduction to the Human Factors of Nontraditional Interfaces

while leveraging the knowledge of expert designers. It is in this spirit that the

Design Guidelines section of each chapter provides some of the most important

lessons that should be applied. The guidelines presented for each interface are

not meant to be exhaustive and inclusive. Rather, the goal of this section is to list

the top 5 to 10 items that an expert would pass along to someone who was looking

for important advice about the human factors implementation of the interface.

Case study of a design:

This section presents a case study of the human factors

specification/implementation/evaluation of the interface over its life cycle.

Where practical, the case study is a real-world implementation. For certain

interfaces, however, proprietary considerations dictated changes in names,

dates, and identifying details to mask the identity of the interface. In some

cases, the example has been made stronger though the use of multiple imple-

mentations rather than a single, life cycle case study.

Future trends:

Since the focus is on nontraditional interfaces, most are still evol-

ving as technology changes and as users (and designers!) become more familiar

and comfortable with their use. This section describes the future of the interface

in the next 10 to 20 years. Where is the interface headed? How will current

implementations change? Will current implementations survive or be sup-

planted by new innovations? What is the end state of the interface when it is

fully mature? In this section, the authors are given a chance to speculate how

a particular interface will mature over time, and what users can look forward to.

The authors of certain chapters, particularly those focused on interfaces that

use sound, have provided access to examples that you can listen to by visiting

the book’s website at www.beyondthegui.com. This website also contains case

studies for each interface. These case studies provide examples of how the inter-

faces have been implemented, and how human factors contributed to those

implementations.

1.2

NONTRADITIONAL INTERFACES

Scarcity of implementation was not the primary factor in determining the inter-

faces to be included in this book, as many of them are nearly ubiquitous. Others,

such as taste interfaces, are quite rare. Further, even though the name of the book

HCI Beyond the GUI

, several chapters do, in fact, deal with GUIs, but in a form

that most designers have little experience with (see, for instance, Chapter 10 on

small-screen design). The 11 interfaces selected for inclusion represent the most

important nontraditional interfaces that a human factors professional should

know and understand.

1.2 Nontraditional Interfaces

1.2.1 Haptic User Interfaces

Haptic interfaces use the sensation of touch to provide information to the user.

Rather than visually inspecting a virtual three-dimensional object on a computer

monitor, a haptic display allows a user to physically “touch” that object. The inter-

face can also provide information to the user in other ways, such as vibrations.

Of course, the gaming industry has led the way in introducing many of these non-

traditional interfaces to the general public. Various interface technologies have

heightened the realism of game play and make the game easier and more compel-

ling. One of the early interfaces to take advantage of haptics can be found in

Atari’s Steel Talons sit-down arcade game (Figure 1.1).

The game was fun to play because the controls were reasonably realistic and

the action was nonstop; however, unlike other contemporary first-person shooter

FIGURE

1.1

Atari’s Steel Talons helicopter simulation, circa 1991.

While the graphics were unremarkable (shaded polygons), the game employed

a haptic interface in the player’s seat (as indicated by the arrow) that thumped

the player (hard!) when the helicopter was being hit by ground fire. The added

interface dimension caused the player to react in more realistic ways to the

“threat” and made the information more salient.

Source:

Retrieved from

www.

mame.net

1 Introduction to the Human Factors of Nontraditional Interfaces

games, Atari integrated a haptic feedback mechanism that was activated when the

user’s helicopter was “hit” by enemy fire. Other contemporary games used sounds

and changes in the graphical interface (flashing, bullet holes) to indicate that

the user was taking enemy fire. Atari integrated what can best be described as

a “knocker” in the seat of the game. Similar in sound and feel to the device in

pinball machines that is activated when the user wins a free game, this haptic

interface was both effective and compelling. Although the information provided

to players was identical to that presented via sound and sight, they reacted to it

differently—their response was evocative of the fight-or-flight response seen in

the real world, and they were more reluctant to just “play through” the warnings,

as is so often seen in strictly visual games.

By selecting the right interface type for the information that must be pre-

sented, the designers created a better interface. Once the sole purview of high-end

simulators and arcade games, haptics can now be found in home game consoles as

well (e.g., Nintendo’s Rumble Pac). Although generally not as sophisticated or

realistic as their more expensive counterparts, the use of vibration in the hand

controller provides the player with extra information about the environment

and game play that was not previously available.

Other examples of compelling implementations of the haptic interface can be

found in interfaces as diverse as automobile antilock braking feedback systems

and threat identification systems for soldiers. Chapter 2 will address the entire

spectrum of haptic interfaces, from simple implementations, such as vibrating

mobile phone ringers, to some of the most sophisticated virtual-touch surgical

simulators.

1.2.2 Gesture Interfaces

Gesture interfaces use hand and face movements as input controls for a computer.

Although related to haptic interfaces, gesture interfaces differ in the noted

absence of machine-mediated proprioceptive or tactile feedback. The simplest

form of gesture interfaces can be found in motion-activated lights—the light inter-

prets the user’s motion as the signal that it should turn itself on. Other commercial

implementations of gesture interfaces have recently begun to make their way into

the game world as well.

In 2001, Konami released a game called MoCap Boxing. Unlike earlier ver-

sions of boxing games that were controlled with joysticks and buttons, Konami’s

game required the player to actually box. The player donned gloves and stood

in a specified area that was monitored with infrared motion detectors. By moving

and boxing, the player could “hit” the opponent, duck the opponent’s hits, and pro-

tect his body by simply replicating the moves a real boxer would make. Figure 1.2

shows the game in action.

This technology, too, has found its way into the home with the recent

introduction of Nintendo’s Wii system. Unlike other current home gaming

1.2 Nontraditional Interfaces

systems, Wii makes extensive use of the gesture interface in a variety of games,

from bowling to tennis, allowing the user to interact in a more natural style than

previously when interaction was controlled via buttons interfaced to the GUI. Not

only is the interface more natural and appropriate for controlling the action in the

games, but it also has the added benefit of getting players off the couch and into

the action, an interface feature that is appreciated by parents worldwide!

As can be seen in Figure 1.3, the Wii bowling game enables the player to inter-

act with the game in a manner that is similar to that of real-world bowling. These

new interfaces have their own problems, however. For instance, shortly after the

Wii was released there were reports of users accidentally letting go of the remote

FIGURE

1.2

Konami’s gesture interface game, MoCap Boxing.

Unlike previous generations of sports games, the user does not use buttons to

code his intentions. Instead, he dons boxing gloves and moves in a motion capture

area (the mat the user is standing on) to control the interface. The end effect is

a fairly realistic game that is intuitive (and tiring!) to use. (Courtesy of Konami.)

1 Introduction to the Human Factors of Nontraditional Interfaces

(particularly in bowling, since that is what people do when they bowl) and having

it crash into, or through, the television [Burnette, 2006]).

Gesture interfaces range from systems that employ hand motion for language

input to those that use gestures to navigate (e.g., “I want to go that way”) and issue

commands (e.g., “Pick that up”) in a virtual-reality environment. Issues surround-

ing the limitations of discriminating gestures and how those limitations guide the

design of these interfaces are explored. In addition, the potential for undesirable

artifacts when using these kinds of interfaces (fatigue, misinterpretation, etc.) will

be discussed along with methods that have been developed to mitigate these

potential deficiencies.

1.2.3 Locomotion Interfaces

Locomotion interfaces, although sharing attributes with both haptic interfaces and

gesture interfaces, differ because they require gross motor movement and

typically deal with large-scale movement or navigation through an interface.

Interfaces in research labs not only include treadmill-type interfaces, but have

moved in other interesting directions as well, including swimming and hang-

gliding applications. These kinds of interfaces are frequently associated with

FIGURE

1.3

Gesture-based interface in action.

The Nintendo Wii, a gesture-based interface, is being played in a bowling

simulation. These kinds of interfaces bring their own unique issues to the

designer.

1.2 Nontraditional Interfaces

high-end simulators, but the technology has recently moved out of the laboratory

and into the commercial realm in the form of body motion arcade games such as

dancing and skiing. As with gesture interfaces, several of the most current genera-

tions of home gaming boxes have body motion controllers available as well. Issues

surrounding the physical limitations of the human body and how those limitations

guide the design of these interfaces will be explored. In addition, the potential for

undesirable artifacts when using these kinds of interfaces (fatigue, vertigo, etc.)

are considered.

1.2.4 Auditory Interfaces

Auditory interfaces have long been used to send simple coded messages across wide

areas (e.g., tolling of church bells, wailing of the civil defense sirens). Auditory inter-

faces have also been used extensively to augment complex interfaces and to spread

the cognitive load in highly visual interfaces, particularly in the conveyance of

warnings. These kinds of auditory interfaces are relatively simple to implement,

but require that the user be able to interpret the meaning of the coded message.

Recently, auditory interfaces have been employed as a substitute for more complex

visual interfaces, and the term “sonification” has been coined to describe these kinds

of auditory interfaces. In a sonified interface, representations that are typically

visual, such as graphs and icons, are turned into sound, that is, sonified, so that they

can be interpreted in the auditory rather than the visual domain.

The chapter on auditory interfaces will detail the fundamental psychophysics

of the human auditory system, and then relate that to the design and implemen-

tation of auditory interfaces. Issues of overload, human limitations, and appropri-

ate selection of auditory frequency space for various kinds of auditory and

sonified interfaces will be discussed.

1.2.5 Speech User Interfaces

Since Ali Baba proclaimed “Open Sesame!” to magically gain entrance to the Den

of the 40 Thieves, speech interfaces have captivated our imagination. With this

imagination further fueled by science fiction television series such as

Star Trek

we have been generally disappointed with the real-world implementations of

speech interfaces because they seem to lag so far behind our idea of how well they

should work. However, recent advances in computing power have brought the

possibility of robust speech interfaces into reality, and commercial systems are

now readily available in multiple realms.

Early implementations of single-word speech command interfaces have led to

continuous–speech dictation systems and state-of-the-art systems that employ

powerful semantic analysis to interpret a user’s intent with unstructured speech.

1 Introduction to the Human Factors of Nontraditional Interfaces

The chapter on speech interfaces will discuss the technology behind these inter-

faces for both speaking and speech recognition systems and chart the progress of

both. It will discuss the implementation of both limited and unbounded vocabulary

interfaces, review the advantages of speaker-dependent and speaker-independent

systems, and detail the appropriate design of speech prompts and navigation struc-

tures. Since speech interfaces have been implemented widely and successfully in

telephone-based systems, extensive examples and case studies of successful

interfaces in this realm will be used to highlight the human factors of speech

user interfaces.

1.2.6 Interactive Voice Response Interfaces

Interactive voice response systems (IVRs) are in widespread use in the commercial

world today, yet receive scant attention in traditional human factors. The interface

has been embraced by the business community because of its huge potential for

cost savings and because when implemented correctly it can result in high cus-

tomer satisfaction ratings from the user as well. Because of the ubiquity of the inter-

face, however, poorly designed IVR interfaces abound, and users are left to suffer.

The chapter on IVRs will discuss the specification of appropriate navigation structures,

prompt construction, and transaction management, including user inputs and

time-out issues. The selection and use of voice persona and the impact on both

user preference and performance will also be considered.

Although IVRs are typically used for routing customers to the right service

agent, or to convey limited amounts of information (like a bill balance), some

current-generation interfaces provide for more interaction and allow significantly

more information to be delivered to the user. These highly interactive IVRs and

the special problems associated with them will be considered as well.

1.2.7 Olfactory Interfaces

Olfactory interfaces have typically been used in situations where widespread

communication of a message is required, but where traditional interfaces are

hampered by the environment. Stench systems to warn miners of danger (where

traditional auditory and visual warnings do not function well) and the use of

wintergreen as a fire alarm signal in factories where there is significant auditory

and visual noise (e.g., a welding shop) are two prime examples of successful olfac-

tory interface implementations. As with many of the interfaces in this book,

the advent of computers and simulated environments has pushed secondary

interfaces, like olfaction, to the fore.

First introduced in the 1960s as a way to add another dimension to theater

movie presentations (where it was a resounding failure), research is continuing

1.2 Nontraditional Interfaces

to be conducted on these so-called “smell-o-vision” interfaces that will allow the

user to experience scents. Unlike the early implementations, research is now

focused primarily on the Internet as a delivery medium in such diverse applica-

tions as shopping (perfume fragrance samples), entertainment (the smell of

burning rubber as you drive a video game race car), and ambience (evergreen

in an Internet Christmas shop).

Of course, the introduction of smell as an interface also has tremendous poten-

tial in training applications in areas such as medicine and equipment maintenance.

When coupled with virtual-reality simulators, the addition of smell may be able

to significantly enhance the training experience. The psychophysics of olfaction

will be discussed in great detail, since the strengths and limitations of the human

olfactory system play a significant role in the correct implementation of these

interfaces. The appropriate uses and technology implementations of current- and

next-generation systems will also be considered.

1.2.8 Taste Interfaces

Without a doubt, interfaces that rely on taste are one of the least explored of

the nontraditional interfaces. Taste interfaces are usually discussed in terms of

simulation, in which a particular taste is accurately represented to simulate a real

taste (e.g., for a food simulator). However, taste can also be used to convey coded

information, much like olfactory displays. Because this interface is in its infancy,

the chapter on taste interfaces will focus primarily on the current state-of-the-art

taste simulator research in this area and the potential for future uses.

1.2.9 Small-Screen Interfaces

Miniature interfaces have been envisioned since Dick Tracy first used his wrist

picture phone, and this vision has become a reality with the successful miniaturi-

zation of electronic components. While devices such as mobile telephones and

MP3 players have continued to shrink, the problems with controlling and using

these miniature devices have grown. From the physical ergonomics associated

with using the systems to the navigation of tiny menus, the new systems have

proven to be substantially different, and more difficult, to use than their bigger

brethren.

The chapter on small-screen interfaces will discuss how these miniature GUIs

are designed and tested, and how special interface methods (predictive typing,

rapid serial presentation of text, etc.) can be employed to make these interfaces

significantly more usable. The chapter will also discuss how to implement com-

mon menu, navigation, and information display structures on both monochrome

and color screens that contain extremely limited real estate, from tiny cell phone

screens to microwave dot matrix displays. Special emphasis will be placed on how

1 Introduction to the Human Factors of Nontraditional Interfaces

to design these interfaces so that the needs of older user populations, who may

have reduced visual and motor capabilities, are accommodated.

1.2.10 Multimode Interfaces: Two or More Interfaces

to Accomplish the Same Task

In many instances, a task can be accomplished using one or more interfaces that

can be used in a mutually exclusive fashion. For example, you can perform simple

banking tasks using the Internet or an interactive voice response system. You can

choose to use either interface method for any given transaction, but they are

mutually exclusive in the sense that the task does not allow or require both to

be used simultaneously. Providing multiple interfaces for single systems means

that the seemingly independent interfaces must be designed and tested together

as a system, to ensure that users who move back and forth between the two inter-

faces can do so seamlessly.

This chapter will explore the more common mutually exclusive multimode

interfaces (MEMM), including IVR/GUI, speech/GUI, small screen/GUI, small

screen/IVR, and small screen/speech, and discuss the human factors associated

with the design and implementation of these multimode interfaces. Appropriate

selection of the different modes will be discussed, as well as consideration of

implementing unequal capabilities in these types of system interfaces.

1.2.11 Multimode Interfaces: Combining Interfaces

to Accomplish a Single Task

In direct contrast to the MEMM interfaces described in Chapter 11, multimode

interfaces that either require or allow the user to interact with the system with

more than one interface at the same time (i.e., a mutually inclusive multimode

[MIMM] interface) are much more common and typically fall into two distinct

classes. The first class of MIMM interfaces are those in which the user can choose

among multiple interfaces during a task, and can move back and forth among

them at any time. For example, systems that combine speech and interactive

voice response interfaces have become more common (e.g., “Press or say one”),

and the way these systems must be designed and implemented is decidedly

different than if each interface were to be implemented alone.

The second class of systems, and by far the most common of any described

in this book, are those interfaces that employ multiple interfaces into a single

“system” interface. Auditory and visual interfaces are frequently combined to

create effective interfaces. Virtual-reality systems are a prime example of this kind

of interface, where vision, audition, speech, haptic, and gesture interfaces are

combined in a single integrated experience. This chapter will focus on MIMM

interfaces that use one or more of the other nontraditional interfaces described

1.2 Nontraditional Interfaces