The electronic world is starting to become an interesting place. From the comfort of our office or home computer, we can read the newspaper, check stock quotes, play interactive games and find factoids on more topics than we ever thought we were interested in knowing about. We can avoid the crowds at the mall by shopping electronically for everything from salami to sweaters, and when we must venture outside, we can book our airplane reservations and rental cars without having to deal with anyone's automated call distribution system. In all these transactions, we can read formatted text and see color images, and (with a little patience) listen to music and speech, and view video fragments-all under control of our index finger.
While this world seems like a very nice place to live -- and in many ways, it is a very nice place -- it brings with it a series of compromises and constraints that reduce the manipulation of information to the presentation of data. (Here a distinction is made between information as an abstract, representation-free entity and data as a particular encoding of that information for a particular use.) In the process, hundreds of years of information presentation rules are being replaced with technology-driven data presentation constraints that are based on a lowest common denominator model of computing interface. Using two-dimensional manipulation devices, the user is thrust into a multi-dimensional world of data fragments which are -- at best -- tied together by one-dimensional hyperlinks: links that connect content without providing context.
The problem, of course, is not in the data stored across the information infrastructure. It is in the interfaces that order, access and consume that data. In the following sections, a brief review of the challenges in making three types of interfaces responsive to the needs of the user is presented.
Interacting with a computer used to be a pretty simple task: in the not-too-distant past, you sat behind a modified electronic typewriter and sequentially produced/ consumed a set of inputs and outputs based on a simple text interface. The interface supported a rigid interaction protocol that was designed to meet the processing constraints of the technology (sequential, serial I/O) rather than the capabilities of the user.
For many years, much of the focus of interface development was on the refinement of the output device: the CRT has evolved from a low-resolution text display into a graphics display that provides a 2-1/2 dimensional visual interface [Foley et al 1990]. At present, the focus of output interface development is to explore the more general use of 3-dimensional displays, augmented with stereo sound capabilities, to support virtual reality output.
Acceptance for changes to the input-side of the technology interface has been less spectacular [MacKinlay et al, 1990]. It has taken more than two decades for a simple two-dimensional pointing device (the mouse) to augment the keyboard as a standard part of the input interface. And although twenty years is a long time, it is apparently not long enough to determine whether a one-, two- or three-button mouse best serves the needs of our five fingers. In this context, it is not surprising that a general move to three dimensional input has yet to begin in ernest, in spite of the fact that various types of three-dimensional manipulation devices (such as three-axis joysticks, which used to be a standard part of the 3-D graphics user interface) have been available for decades.
The primary challenge in the development of the technology interface is the need to balance the capabilities of the input and output interfaces. In particular, the parallelism in real life that is starting to be modeled at the output interface will need to be mirrored by an increased parallelism at the input interface.
The integration of parallelism into the input
interface will not necessarily require a new
generation of computer users: there are many
examples of user interfaces from "real life" in
which parallelism is commonplace. Consider
the actions required to make a left turn in a
left-hand drive, standard-transmission
automobile:
(In the United States, this activity is often
supplemented by the need to balance a donut
and a cup of coffee, while in many parts of
Europe `turn time' is seen as an appropriate
moment to further engage the hands/eyes/
mouth in offering constructive suggestions to
nearby motorists and pedestrians.)
The point of the example is not that driving
is difficult -- with a bit of training, most
motorists can do it safely most of the time. The
point is that the technology-imposed
constraint of sequential input from one or two
serial sources limits the effectiveness of
human/computer interaction. (Anyone who
has used a PC-based automobile or flight
simulator knows this all too well.) Unlike real
cars or professional simulators, a modern PC
is a multi-purpose tool that needs to be
configured for many uses. Defining a generic
but flexible input interface that matches the
abilities (and disabilities!) of the user is
perhaps the greatest interface challenge facing
the HCI community.
Where technology provides the physical
facilities available to a user, the presentation
interface determines how the physical
interfaces can be combined to control a
particular flow of data.
Most "current" computers provide a
mechanism for presenting information of
various types: text, images, audio files, videos,
etc. Such support for multiple independent
media has served as a catalyst for the support
of multimedia. The key distinction between
multi- and multiple-media is the degree of
coordination among media during
presentation.
Under various circumstances, it may be
appropriate for media coordination control to
be defined by the multimedia author. At other
times, the end user may best control the
presentation. On the Web, presentation
control is usually removed from both author
and end user, and placed in the local
browser -- probably the least appropriate place
to put it, from a presentation-quality control
perspective.
The challenge in designing future
presentation interfaces is to allow a particular
presentation to be scaled to match the
capabilities of a particular presentation
environment [Hardman et al 1994].
The problems at this top level of the
information hierarchy span a range of
interface issues: placing content-based
anchors in non-text encodings; integrating
information from several sources with
preservation of context; providing access
charging models that serve as an incentive to
make information available (and protect the
rights of the content owners) rather than
limiting use based solely on economic power;
providing adaptive delivery systems that can
tailor the quality of the data presented to the
resources available locally and globally;
content-based access, where the definition of
content relations can change as a function of
user interests or historical use; and scalability
of presentations, so that browsing can be
efficiently separated from detailed
information consumption.
The added value of computer-based
information access should not only be the
transport of data fragments from world-wide
sources to the home or office. It should be the
ability to filter, integrate and associate data so
that the user is able to get focused information
from the information infrastructure.
The development of the human/computer
interface has many facets. The current
generation of devices and presentation tricks
has provided a basis for experimentation, but
a next generation of interface tools needs to be
developed that is less centered on available
technology and more on the basic needs of
information communication. From our
perspective, the problems have less to do with
device development than integrating time and
quality as first-class attributes of how
information is saved, presented and
integrated. The promise of multimedia
computing may be that control over
interaction will move from the implementor to
the user-but before that happens, the user
needs to be empowered with control
mechanisms that allow information and not
just raw data to be manipulated.
Interfacing to the Presentation
Summary
References