ABSTRACT
Understanding and exploiting the abilities of the human
visual system is an important part of the design of usable
user interfaces and information visualizations. Good design
enables quick, easy and veridical perception of key components
of that design. An important facet of human vision is
its ability to seemingly effortlessly perform “perceptual
organization”; it transforms individual feature estimates
into perception of coherent regions, structures, and objects.
We perceive regions grouped by proximity and feature similarity,
grouping of curves by good continuation, and
grouping of regions of coherent texture. In this paper, we
discuss a simple model for a broad range of perceptual
grouping phenomena. It takes as input an arbitrary image,
and returns a structure describing the predicted visual organization
of the image. We demonstrate that this model
can capture aspects of traditional design rules, and predicts
visual percepts in classic perceptual grouping displays.
Author Keywords
Perceptual organization, grouping, good continuation, proximity,
similarity, Gestalt, contour integration.
ACM Classification Keywords
H5.2. User interfaces, theory & methods.
INTRODUCTION
Design of user interfaces and information graphics is poorly
understood, and somewhat hit-or-miss in terms of effectiveness.
A number of issues influence the success of a
design, and these run the gamut of the underlying human
behavior. A design must be good cognitively (can the user

easily understand the semantic structure of the design?),
perceptually (can they effortlessly interpret the visual information
present in the design?), and socially (does the
design fit into the user’s workflow? will they want to use
it?). Here we focus on perceptual aspects of design.
Perhaps the most important aspect of human vision for design
is perceptual organization. Perceptual organization
refers to phenomena in which the visual system quickly and
seemingly effortlessly transforms individual feature estimates
into perception of coherent regions, structures, and
objects. These phenomena were first studied in detail by
the Gestalt psychologists, who produced a set of qualitative
Gestalt principles that govern pattern perception [1, 2], including
but not limited to: the tendency of things to group if
they are nearby (the Gestalt law of proximity); if they share
similar features (the law of similarity), or are smooth and
continuous (the law of good continuation). The duals of perceptual
grouping are important phenomena in their own right:
we quickly and effortlessly perceive boundaries between
certain visual textures, perceive edges between coherent regions
in an image, and quickly detect unusual items that
seem to “pop out” from the background. Examples of perceptual
grouping phenomena are given in Figure 1.
Following the visual system’s “rules” of visual organization
makes interpretation of visual aspects of designs effortless:
a user easily sees which labels refer to which parts of a diaa
b
c
d
e
f
Figure 1: Perceptual grouping examples, including
grouping by proximity & similarity (a, b), and grouping
by good continuation (c, d). (e) A user interface; what
is the percept? (f) A graph, from [5]. Will a user
perceive the trend of the data?
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CHI 2009, April 4–9, 2009, Boston, MA, USA.
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CHI 2009 ~ Cognitive Modeling and Assessment April 8th, 2009 ~ Boston, MA, USA
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gram, notices a trend in data, and makes connections between
the “overview” and the “detail” in a map. Good designs
use the natural perceptual processing power of the
brain, and interpretations of such designs are fast, robust to
instruction, and cross-cultural [3]. With poor visual design,
the grouping structure may not match the structure of the
information, leading to confusing displays [for examples,