Configural Processing Consortium (CPC) 2007: Program
Wednesday, November 14, 2007
Hyatt Long Beach
Long Beach, CA
Configural Processing Consortium (CPC) is a workshop focusing on configural
processing. Specifically, our goal is to define the major problems underlying the study of
configural processes in humans. General audience presentations are open to the public.
Further information can be downloaded from our website:
http://www.indiana.edu/~psymodel/CPC2007.shtml
Organizing committee (listed alphabetically):
Ami Eidels, Phil Kellman, Ruth Kimchi, Mary Peterson, Jim Pomerantz, Jim Townsend.
Meeting’s schedule (Harbor ABC room):
08:30 – 09:00: Arrival (coffee)
09:00 – 09:30: Announcements
09:30 – 10:10: Welcoming and General audience talk I (Phil Kellman)
Title: “A Computational Gestalt Agenda for Perception and Learning”
10:10 – 12:10: Morning session [discussant: Glyn Humphreys]
Speakers (by order of presentation): Jim Pomerantz, Patrick Gariggan, Jim
Bartlett, Alan Gilchrist, Jim Townsend, Viktor Sarris, Glyn Humphreys.
12:10 – 13:10: Lunch (we will provide lunch boxes)
13:10 – 13:50: General audience talk II (Steve Palmer)
Title: “Configural Effects in Aesthetic Preference and Goodness-of-Fit”
14:00 – 16:00: Afternoon session [discussant: Rob Goldstone]
Speakers (by order of presentation): Michael Kubovy, Evan Palmer, Rutie
Kimchi, Zyg Pizlo, Johan Wagemans, Ami Eidels.
Jim Pomerantz presenting the Configural Processing Wikispace.
16:00 – 16:40: General audience talk III (Mary Peterson)
Title: “Biased Competition in Figure-Ground Perception”
17:00 – 17:45: General discussion (Facilitated by Goldstone, Humphreys, and Kubovy)
18:00
Closing
18:30
Banquet (provided; Sea View Rotunda room)
Participants (listed alphabetically):
Jim Bartlett, Boaz Ben-David, Ami Eidels, Mario Fific, Patrick Garrigan, Alan Gilchrist,
Rob Goldstone, John Hummel, Glyn Humphreys, Helena Kadlec, Phil Kellman, Ruth
Kimchi, Michael Kubovy, Mary Peterson, Zygmunt Pizlo, Jim Pomerantz, Mary Portillo,
Jane Riddoch, Viktor Sarris, Jim Townsend, Johan Wagemans
How Do Holistic and Part-Based Perceptual Processes Affect Recognition Memory?
James Bartlett
University of Texas, Dallas
A fundamental question is whether general theories of memory extend to stimuli such as
faces that can be processed in a configural and/or holistic fashion. I consider three
possible answers which are “yes,” “no,” and “partly.” From the last of these questions a
new question emerges: How do domain-specific or domain-related configural-holistic
processes interact with general memory processes of familiarity, recollection, and
memory-editing? A promising approach to this new question is provided by the
“conjunction effect” – the frequent false recognition of new stimuli that recombine the
parts of previously studied stimuli. The conjunction effect is robust with faces, even
naturalistic faces in upright orientation with which configural-holistic processing is
presumed to be the norm. I discuss old and new data on the conjunction effect with
upright faces, inverted faces, objects and verbal stimuli. These data suggest that holistic
and part-based perceptual processes can be distinguished from two general memory
systems that: (a) contribute to hits as well as conjunction false alarms, and (b) control
false alarms in response to conjunctions as well as new items. Remarkably, there are
individual differences in the balance of holistic versus part-based processing, and these
appear independent of individual differences in general memory processes.
Towards a Unified Theory of Configural Processing
Ami Eidels
Indiana University
Capacity and coactivation (e.g., Townsend & Nozawa, 1995), configural superiority
effect (e.g., Pomerantz, Sager, & Stoever, 1978), human vs. ideal observer thresholds
(e.g., Gold, Bennet, & Sekuler, 1999), and Garner interference (Garner, 1974) are but few
of the measures with which we estimate, sometimes define, what we believe to be
configural processing. A unified theory of configural processing should at least attempt to
find relationships among the different measures, perhaps represent them on a common
space. A possible first step is to define a standard set of stimuli, maybe even a standard
procedure, which we shall employ in future research. Then, results from different
experiments and from different labs can be compared. I will discuss each of the measures
and provide a tentative example of possible stimuli. This is just one of several short term
goals that we can specify as part of a concerted effort to define and measure configural
processing.
Efficient Coding of 2D Shape
Patrick Garrigan
Saint Joseph’s University
Implicit in many theories of how the visual system represents shape are the ideas that the
geometric information in stimuli is often complex and some tradeoff between economy
and resolution will typically be necessary. For these reasons it is natural to
apply information theoretic techniques to understanding how shapes might be best
encoded by the visual system, given constraints of noise and capacity. A general theory
of how all the shapes in the world should be optimally encoded is, however, difficult to
establish because the statistics of shape are hard to quantify. Instead, we can look to
behavioral evidence to guide theories of shape encoding. Redundancy in the
representation of shape information can either be minimized to produce the shortest
possible code or incorporated into the representation for error correction in the presence
of noise. I will argue that there is evidence that the visual system’s representations of
shape use both of these techniques.
Gestalt theories and the problem of perceptual errors
Alan Gilchrist
Rutgers University
Decomposition models of perception, such as intrinsic image models of lightness,
Johansson’s model of common and relative components in motion, and Bergstrom’s
analogous model in color, yield percepts that are both the simplest percepts for a given
stimulus and highly veridical. Yet they fail to account for the pattern of errors shown by
humans. Perceptual errors, including both illusions and failures of constancy, are
ubiquitous. And because they are systematic, not random, their pattern must be highly
diagnostic of the visual software. Gestalt theories of lightness advanced by Kardos (1934)
and Gilchrist et al (1999) explicitly and successfully account for errors using concepts of
grouping, frames of reference, and crosstalk between frameworks, but do not obviously
invoke the simplicity principle. How might a gestalt approach based on simplicity explain
the errors? It would seem reasonable to attribute perceptual errors to failures in the
components of a decomposition model, such as an underestimation of the common
component, or a failure of edge classification. Such an approach has not been successful
to date, but might reward further exploration.
Action Relations as a Configural Cue
Glyn W. Humphreys & M. Jane Riddoch
University of Birmingham, UK
Recently we have demonstrated that action relations between objects enable the objects to
be 'bound together' as a single perceptual unit (Riddoch et al., 2003, Nature
Neuroscience). In this talk we will evaluate the factors that lead to this perceptual binding
between objects in action relations. We ask whether the effects are automatic, whether
they are contingent on familiarity, on the presence of covert motion between the objects,
and whether the bound unit operates in any way like a perceptual configuration. The
evidence points to action relations being an important cue for configural coding.
A Computational Gestalt Agenda for Perception and Learning
Philip J. Kellman
University of California, Los Angeles
Basic issues advanced by the Gestalt psychologists almost a century ago still
define crucial priorities in cognitive science and neuroscience. A key set of issues
involves elements, relations, and abstraction in perception. I will highlight this issue in
vision models, where a crucial challenge is relating early, non-symbolic encodings (e.g.,
activation of local contrast-sensitive units) to abstract descriptions and relations (such as
contour and object shape). A related set of Gestalt issues involves seeing structure and
“insight,” pointing to crucial but mysterious links among perceiving, thinking, and
learning. I will show how these issues relate to efforts to understand abstract perceptual
learning. I will also argue that perceptual learning is a neglected dimension of learning in
instructional contexts, and that it is a major component of learning even in high-level,
symbolic domains.
How do we make progress in these areas? I will suggest that many problems
center on identifying a “grammar” of relational encoding that begins at early processing
stages. Some of this recoding is automatic and constrains what can be perceived and
learned. Other recoding allows synthesis of new relations with experience, allowing us to
discover even higher-order structure. Characterizing such a grammar of perception and
learning will be difficult, but will benefit from grounding in ecological analyses (as in the
work of James Gibson and David Marr). Likewise, I will suggest that both computational
understanding and instructional utility will advance from merging Gestalt ideas about
structure and “insight” with perceptual learning concepts (as in the work of Eleanor
Gibson).
What does it mean that “the whole is different from the sum of its parts”?
Explorations with face discrimination
Rutie Kimchi & Rama Amishav
University of Haifa
One way to capture the Gestaltists’ tenet that “the whole is different from the sum of its
parts” is that a whole is qualitatively different from the complex that one might predict by
considering only its parts. We report recent attempts to examine the implications of this
notion of configural processing (e.g., processing dominance of configural properties) in
the context of face perception, given that configural processing is considered to be the
hallmark of face perception. In doing so, we address the following three questions: 1)
Does the discriminability of face components (i.e., eyes, nose, mouth) determine the
discriminability of the whole face? 2) Is the discriminability between faces that differ in
configural properties (spatial relation between components) easier than between faces
that are similar in configural properties, regardless of the discriminability of the
components? 3) Is there perceptual dependence/independence, as indexed by selective
attention (Garner interference), between components, and between components and
configural properties? The implications of behavioral data pertaining to these questions
will be discussed.
A possible link between conjoined grouping principles AND
{weak fusion OR stochastic integration}
1
Michael Kubovy1 & Sergei Gepshtein2, 3
Univ. of Virginia; RIKEN Brain Sciences Inst. [Wako-shi, Japan]; 3Salk Institute
2
It has recently been discovered that when two grouping principles (proximity and
similarity) are conjoined, their joint effect on grouping strength is an additive
combination of their separate effects on grouping strength, and that across observers
there is a high negative correlation between their contributions. We argue that this is just
what would be expected from the application of a maximum-likelihood estimation
(MLE) approach -- commonly used to describe phenomena of sensory integration -- to
grouping. But the evidence of negative correlation is also consistent with a decision
strategy known as stochastic integration, by which observers use one factor of grouping
at a time and do so probabilistically.
Perceiving Dynamically Occluded Objects
Evan Palmer
Wichita State University
In a world of mobile objects and observers, accurate perception of shapes requires
processes that overcome fragmentation in space and time. When an object moves behind
an occluding surface with many apertures, perception of its shape is remarkably robust
and precise. This accurate shape perception occurs even though fragments of the
dynamically occluded object appear at different times and places. We developed the
theory of Spatiotemporal Relatability to account for observers’ perception of dynamically
occluded objects. Spatiotemporal Relatability proposes that when parts of objects move
behind an occluding surface, their shapes and positions continue to be perceptually
available even though they are physically occluded. The positions of persisting but
occluded fragments are updated over time in accord with the object’s observed velocity
so that visible and occluded fragments can be connected together to form units. We
propose the dynamic visual icon representation as the mediator of these persistence and
position updating processes. This elaboration suggests that the visual icon may be more
versatile than previously suspected. Under this new view of object completion, motion is
an integral part of all shape perception processes and static images are merely a special
case in which velocity is equal to zero.
Configural Effects in Aesthetic Preference and Goodness-of-Fit
1
Stephen E. Palmer1, Jonathan Gardner1, & Stefano Guidi2
University of California, Berkeley; 2University of Sienna, Italy
We will report on two related projects that concern experiential dimensions that appear to
be dominated by similar configural factors. The first concerns aesthetic response to the
spatial configuration of simple images containing one or more familiar objects within a
rectangular frame. Our results show the effects of several powerful, configural variables,
including a "center bias" in lateral placement, an "inward bias" in lateral placement, and a
"lower bias" in vertical placement. The second concerns people's experience of the
"goodness of fit" for a probe shape ( e.g., a small circle or triangle) within a surrounding
rectangle (cf. Palmer, 1981). Such ratings also reveal the importance of the center of the
frame and pointing inward within the frame, as well as striking evidence for the role of
symmetry and balance in spatial composition. The relation between these two lines of
research will be described in terms of expectations generated by the structure of the
rectangular frame and its relation to the structure of the object(s) it contains.
Biased Competition in Figure-Ground Perception
Mary A. Peterson
University of Arizona
To perceive configurations, one must perceive shaped entities, or "figures," yet the
processes producing shape perception are not yet understood. Progress has been
hampered by three mistaken assumptions (1) figure-ground segregation is an early and
separate stage of processing, (2) this early stage produces a coupled output of shape and
relative distance, and (3) there exists a border ownership process. I will review
behavioral and neurophysiological evidence indicating that figure-ground perception
results from competition between two candidate shapes that might be seen; that
suppression is an integral part of this process; and that suppression can spread from one
part of the visual field to another. I will close by proposing that figure-ground perception
lies at one end of a continuum of processes explained by the biased competition model of
attention.
Symmetry and Shape
Zygmunt Pizlo & Tadamasa Sawada
Purdue University
It is quite well established that human observers can quickly and reliably detect
symmetrical patterns on the retina. Symmetry detection is important because (i) many
objects "out there" are symmetrical, and (ii) symmetry is a form of redundancy.
However, a retinal image of a symmetrical object is itself almost never symmetrical.
Instead, it is "skewed symmetrical". Can human observers detect skewed symmetry? The
answer is "YES". The ability to detect skewed symmetry is of fundamental importance
for shape perception because the application of symmetry constraint to a single 2D retinal
image leads to an accurate recovery of a 3D symmetrical shape. We will argue that the
visual system uses symmetry not as a form of redundancy, but rather as a rule of
perceptual organization.
The Experience Error Revisited
James R. Pomerantz
Rice University
In psychological research, nothing matters more than understanding and describing the
stimulus correctly. Whether it entails only a simple visual pattern on a display or
multisensory, 3D scenes with assorted objects and agents, an accurate and complete
description is necessary both for scientific communication –allowing others to replicate
our studies – and for helping us understand what parts of a stimulus are effective in
engaging cognition and behavior. We sometimes portray our stimuli inaccurately and
commit the experience error, however, by describing the stimulus as we see it rather than
how it may actually be. In essence, we confuse our perceptions of the world with the
stimulation we receive from it, wrongly attributing perceived structure to the proximal
stimulus. By presuming the stimulus is what we see it to be, we confuse stimuli with
responses, with our percepts. We illustrate this phenomenon with several common
examples, show why they matter, and suggest ways in which research and theory in areas
including the perception of objects and wholes may be advanced by addressing the error.
Transposition, Relation, Relational Perception, and Comparative Psychophysics
Viktor Sarris
Frankfurt A.M., Germany
The gestalt premise of relational perception is inherent in all kinds of „transposition“
(relational perception), both in humans and other animals. This is demonstrated in my
talk on my comparative frame-of-reference experiments with either two-stimulus
(unidimensional) orfour-stimulus (twodimensional) postgeneralization context-test
procedures. For instance, in the unidimensional case both the animal and human subjects
showed marked and lawful psychophysical context effects, at least within a certain
stimulus range (testing-the-limits approach); however, in the multidimensional case (fourstimulus paradigm) the respective transposition behavior followed very different response
rules for the different species investigated (cf. Sarris, Relational psychophysics in humans
and animals: a developmental-comparative approach. Psychology Press, London). Of
our main interest here are the crucial, still unsolved problems as related to Questions 1 &
2, namely the issues of the relational processing involved and its connection to
“configural” (integral vs. separable dimensions) responding: How is, or may be, their
age-dependent and comparative analysis to be conceived by some relevant predictive
quantitative modelling and explanatory theorizing? In this context the role of “similarity”
in multidimensional configural processing needs to be emphasized.
Emergence Pictured through Dynamics
James T. Townsend
Indiana University
The concept of emergence has been challenging to define in a precise manner. Some
attempts at general definition seem vague and un-resolvable. Ambiguous figures and
hidden figures are reasonable exemplars which deserve the term. I propose that one
reasonable approach to this concept rests in the general field of mathematical dynamics.
Certain concepts that appear meaningful in the context are discussed.
On groups, patterns, shapes and objects: The many ways in which multiple elements
interact
Johan Wagemans
University of Leuven, Belgium
Perceptual grouping, figure-ground organization, shape perception and object recognition
are all domains in which configural processing plays a role but theoretical synthesis has
been hampered by the diversity of stimuli and experimental paradigms. We have
attempted to study interactions between different component processes and to facilitate
cross-domain comparisons of results by using different kinds of stimuli consisting of
multiple Gabor patches. In Claessens and Wagemans (2005, Perception &
Psychophysics, 67, 1446-1459), we have investigated the interactions between proximity
and alignment in so-called Gabor lattices (analogous to the Kubovy & Wagemans dot
lattices but with Gabor patches instead of dots). In a second line of research (with Bart
Machilsen), we have asked observers to discriminate open contours (“snakes”) from
closed contours (“shapes”) consisting of Gabor elements against a random background,
and we have compared symmetric to asymmetric shapes. In a third line of research (with
Geir Nygård), we have presented Gabor patches on the contour and on the interior
surface of outlines derived from objects and we have compared detection, discrimination,
and identification. In a fourth line of research (with Lizzy Bleumers), we have asked
observers to localize shapes (contours with Gabor elements) and we have compared
upright to inverted object outlines. I will discuss the many different kinds of interactions
between local elements in these different contexts.