CHI 2002 Poster

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A Framework for Locomotional Design:
Toward a Generative Design Theory

Susanne Jul
University of Michigan

A poster presented at CHI 2002. See also
Jul, S. (
2002). A Framework for Locomotional Design: Toward a Generative Design Theory. ACM Conference on Human-Factors in Computing Systems, CHI 2002 Extended Abstracts, 862-863.

Poster Overview

Locomotion -- purposeful directed movement -- can be seen as fundamental to navigation. This yields

  1. A conceptual framework of the rôle of locomotional design in navigational cognition, and of
  2. The elements of locomotional design that affect navigational cognition, and
  3. A set of principles to guide design,

leading, eventually, to a generative design theory (1) of navigational design.

1. Generative Design Theory

Generative design theory in the usability engineering cycle

The purpose of a generative design theory is to guide designers in generating viable design alternatives, much as music theory guides music composition.

Generative design theory is prescriptive of design rather than descriptive of behavior.

A generative design theory of human-computer interaction should

2. Locomotion: A Navigational Task

Locomotion -- purposeful directed movement
is in service of navigation -- finding and getting to places
which is in service of the user's task.

Locomotional design -- the support an environment offers for moving and directing movement
dictates problems of wayfinding -- spatial problem-solving and decision-making necessary to navigation
and determines (in part)

3. Locomotional Design Elements

Locomotional Structure

The network of locations at which movement can be stopped and routes along which movement is possible, (e.g., a freeway system and the towns to which it leads):

Locomotional Mechanism

The means of actually moving and of directing movement, (e.g., automobiles):

4. Using Locomotional Design to Increase Wayfinding Performance

Derive basic locomotional structure and mechanism from navigational needs and the user's task:

5. Example: Inter-Object Navigation in Jazz

Jazz is a 2D multiscale environment with a zooming user interface

  1. Objects are laid out on an infinite 2D surface

  2. The surface can be viewed at an infinite range of magnifications

  3. Objects can change their appearance depending on the magnification (scale) at which they are being displayed

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Conventional Locomotion

Conventional locomotion in Jazz is defined relative to the space itself

Task-Based Locomotion



Design (Predictive Targeted Movement)

Zoom-in  Zoom-in Top of the World

Experimental Results

Conventional and task-based locomotion was compared in an experiment using a within-subject design with repeated measures (24 subjects)

  % difference t(23) p <
Time on task -30% 4.93 .0001
Proportion of task time spent moving view +13% 3.86 .001
Proportion of task time spent moving mouse -25% 6.84 .0001
Proportion of time spent moving mouse while view moving -35% 7.24 .0001
Proportion of time spent moving mouse while view is stationary -13% 3.62 .005
Proportion of mouse move time spent dragging mouse -3% .53 .6

Differences in time usage (task-based locomotion relative to conventional locomotion)