"Animation at the Interface
- Ronald Baecker and Ian Small
from B. Laurel, ed. The Art of Human-Computer Interface
Design
review by Harry Hochheiser
Summary
In Animation at the Interface, Baecker and Small present an
early and intriguing overview of possible uses of animation in the
user interface. In the context of a categorization of potential
uses of animation, the authors present several novel and
interesting suggestions for the use of animation as a tool to
illustrate the mechanics of an interface. The focus of this paper
is clearly (and appropriately) on the user: ""Hardware and
software considerations are secondary to the purpose of
the image and the user's tasks and goals."
After a brief introduction to techniques used in the production of
computer animation, Baecker and Small present three major aspects
of a system that animation might illustrate:
- Structure
- Process
- Function
While the boundaries between these categories are not necessarily
clear - and the potential overlaps are not explicitly acknowledged
- these categories provide a good starting point for discussion of
the potential uses of animation.
Animation of structure involves the use of animation to
present and explore environments and situations that model
real-world counterparts, in a manner that extends the visual
capabilities beyond those found in the real world. Implicit in the
description is the assumption that animation will add enough
information to a static display to justify the computational
cost. In discussing the use of animation to simulate the growth
of vegetation, the authors touch upon an intriguing possibility:
the use of animation to illustrate events along a distorted time
scale.
Animation of Process can be used to understand processes
such as operation of algorithms. Baecker and Small argue
(without much supporting evidence) that animated illustrations
of algorithms will make the operations of the algorithms easier
to understand.
Animation of Function is the focus of article. The
claims for the benefits of animation, and the types of animation
bear repeating: the authors claim that "can help cut
through the complexity of an interface", to illustrate the
capabilities of the interface and to suggest actions that should
be taken or avoided. Eight uses of animation are proposed:
- Identification: identifying applications when they are
invoked.
- Transition: Illustrate changes in system state that effect
the interface. For example, opening of a window might be
accompanied by an animation of an outline for the new window
as it grows to full size.
- Choice: Animation of menus in order to improve efficiency of
display and indication of the relationship between items.
- Demonstration: The use of animation icons to improve the
clarity of description of functions associated with those
icons.
- Explanation: "Guided tours" that illustrate the
use of the interface to achieve a goal by presenting the steps
involved in an animated sequence.
- Feedback: progress bars and other indicators that present
visual cues indicating the progress of the system towards
completion of a given goal.
- History: replaying of user activities in order to explain
the steps that were taken to arrive at a particular state.
- Guidance: "histories of the future" that would help a user
determine what the impact of various interactions alternatives
might be.
For each of these applications of animations, concrete scenarios are
presented. Some of these - like the progress bar (feedback) and
the window outlines (transition) - have become familiar and
commonplace in modern interfaces, while others - such as the
animated icons - are less common.
Analysis
This paper seems to be a relatively early paper on the topic, written
at a time when animation in the interface was used relatively
infrequently. As such, it is mostly speculative in nature,
presenting an agenda for future research and suggestions for
interface designers.
In reading this article, I was struck by the vague and informal nature
of their arguments for the effectiveness of animation. While the
widespread use of animation in modern interfaces would seem to
support the claim that animation is beneficial, Baecker and
Small seem to rely on intuitive arguments, without providing a
clear framework that can be used to evaluate and understand the
benefits of animation. It almost seemed to me as if the authors
were assuming the benefits of animation as a given, without
adequately justifying this position.
This shortcoming was particularly distressing when seen in terms of
the lack of any discussion of the downsides of
animation. While the authors acknowledge the problems that may
be associated with animation - "a pulsating display and a
riot of information that the user would not be able to
assimilate easily" - their comments on judicious use of
animation are minimal - " Good design is essential".
To be fair, detailed evaluation of the uses and abuses of animation
may have been premature at the time of writing of this paper. In
many ways, this paper asks more questions than it answers.
Several scenario descriptions conclude with calls for research
to evaluate the effectiveness of the techniques as described.
I found it interesting to consider this paper in relation to existing
interfaces: which suggestions have been incorporated into
Windows95/98/NT, and which have not?
Questions
- When is animation noteffective? What are the downsides to
the use of animation?
- In evaluating the effectiveness of animation, what steps should
designers take to avoid the "isn't that neat" effect
that might lead users to like and enjoy animated interfaces?
To what extent should user satisfaction be considered a
sufficient criteria for success of animated interfaces?
- Have all of these scenarios been implemented? Which have worked,
and why? Which have not, and why?
- Animation might not be suitable for all users - particularly for
users with poor vision. Has any research been done to
investigate secondary cues that might be used along with
animation?