Abstracts 2005 - The Psychonomic Society

Posters 5001–5008 Saturday Evening
POSTER SESSION V
Sheraton Hall, Saturday Evening, 6:00–7:30
• VISUAL PROCESSING •
(5001)
The Poggendorff Illusion: Rectangle Fill Patterns Alter Illusion
Magnitude. CLARE K. PORAC, Pennsylvania State University, Erie,
& ALAN SEARLEMAN, St. Lawrence University—Masini et al. (1992)
found that illusion magnitude (IM) in the Poggendorff is lowest when
the inducing rectangle is filled with lines resembling the figure’s
oblique line. IM is highest when the rectangle is filled with lines that
mimic the straight lines in the inducing rectangle. In Experiment 1,
six Poggendorff figures were presented with vertical rectangles that
were filled with vertical lines of high and low spatial frequency or
horizontal lines of high and low spatial frequency or were solid white
or black. In Experiment 2, the same six Poggendorff figures were presented
with a horizontal rectangle. IM was highest in Experiment 1
when the rectangle was filled with low spatial frequency vertical lines.
In Experiment 2, IM was highest when the rectangle was filled with
vertical lines. Vertical line fill causes higher IM regardless of the orientation
of the straight lines in the rectangle.
(5002)
ART Theory Accounts for Perceived Changes in Perspective Pictures
Due to Eye Height. IGOR JURICEVIC & JOHN M. KENNEDY, University
of Toronto, Scarborough—A problem that has been with the
study of vision since the Renaissance is our reaction to perspective in
pictures. Perspective pictures of square tiles can be drawn using a high,
low, or intermediate eye height. When the eye height is low—that is,
close to the ground—many quadrilaterals that depict squares appear
compressed. But increase the eye height and the apparent compression
decreases, producing quadrilaterals that appear square or even elongated.
A two-factor angles and ratios together (ART) theory explains
which quadrilaterals appear compressed, square, or elongated across
the different eye heights. The ART theory’s two factors are (1) the ratio
of the visual angles of the tile’s sides and (2) the angle between the normal
to the picture plane from the observer and the direction to the tile
from the observer. We point out implications for constancy.
(5003)
Asynchronous Priming in the Gamma Band Facilitates Discrimination
of Kanizsa-Type Forms. ROBERT G. MORRISON, Xunesis,
& HONGJING LU, JOHN E. HUMMEL, & KEITH J. HOLYOAK,
UCLA—We investigated the role of temporally structured priming in
discrimination tasks involving perceptual relations between multiple
Kanizsa-type figures. Visual information presented as asynchronous
flicker in the gamma band can modulate the perception of multiple objects
in a subsequent display, decreasing response time to identify and
discriminate relations between the objects. Our findings provide support
for the JIM model of visual binding.
(5004)
The Flash-Lag Effect Is Modulated by Accumulating Preprobe
Excitation and Postprobe Inhibition. MICAH GEER & WILLIAM C.
SCHMIDT, SUNY, Buffalo—The flash-lag effect occurs when observers
perceive a flashed probe to lag spatially behind a moving target even
though both were physically aligned at the time of the flash. The present
research manipulated properties of the target theorized to modulate
the speed at which signals from moving stimuli are neurally
processed. The results are at odds with a number of explanations of
the effect and are predicted exclusively by an account that relies on
accumulating subthreshold excitation and cumulative lateral inhibition
induced in cortical maps by the moving stimulus.
(5005)
Eye-Movement–Based Biometric Measures. FRANK M. MARCHAK
& TANNER L. KEIL, Veridical Research and Design—Kasprowski and
124
Ober (2005) describe a method for characterizing eye movements to
a moving point that can capture differences among individuals and
uniquely identify a specific individual. In this work, we attempt to
produce a similar result by characterizing eye movements to static images
of natural scenes. Standard eye movement measures based on
fixation and saccade data were examined for subjects repeatedly viewing
the same images. A selection of classification techniques were applied
to these data to determine a set of parameters that could
uniquely identify an individual. We present the results of these efforts,
both positive and negative, and discuss the implications of the use of
eye movements as a biometric measure.
(5006)
The Development of Sensitivity to a Common Region as a Perceptual
Organizational Principle. ANGELA HAYDEN & RAMESH S.
BHATT, University of Kentucky, & PAUL C. QUINN, University of
Delaware—We examined whether 3- to 4-month-olds and 6- to 7month-olds
exhibit sensitivity to a common region as an organizing
principle. Infants were familiarized to two rectangles, one of which
contained two stars. Older infants looked longer at a novel pattern in
which one of the stars was now located in the other rectangle than at
a pattern in which the star was displaced the same amount but still
within the same rectangle. Infants in a control condition in which the
organization was not based on a common region failed to discriminate
between analogously modified patterns. Thus, 6- to 7-month-olds exhibited
evidence of sensitivity to a common region. However, 3- to 4month-olds
failed to exhibit similar sensitivity in this study and in a
subsequent study with simpler patterns. These results indicate that the
principle of common region is functional in infancy, although not until
sometime after 3–4 months of age.
(5007)
Configural Processing of Faces and Objects: An ERP Study of the
Thatcher Illusion. LUC BOUTSEN, Aston University, & GLYN W.
HUMPHREYS, PETER PRAAMSTRA, & TRACY WARBRICK, University
of Birmingham—In the Thatcher illusion, a face with inverted
eyes and mouth looks abnormal when upright, but not when inverted.
Behavioral studies have shown that Thatcherization of an upright face
disrupts perceptual processing of the local configuration. We studied
ERP correlates of the illusion during the perception of faces and nonface
objects, to investigate whether inversion and Thatcherization affect
similar neural mechanisms. Observers passively viewed faces and houses
in four conditions (upright vs. inverted and normal vs. Thatcherized)
while detecting an oddball category (chairs). Thatcherization modulated
N170 to faces, but not to houses, over the occipito-temporal cortex.
This modulation matched the illusion, since it was larger for upright
than for inverted faces; it occurred for whole faces and parts. P1 was
unaffected by Thatcherization but was modulated by inversion. Face
Thatcherization affected P2, whereas inversion affected P2 across categories.
These results suggest that inversion and Thatcherization disrupt
perceptual encoding of faces and objects differently.
(5008)
Do Affordances Change With Changes in Body Shape? WILLIAM
LANGSTON & CHARLOTTE TIDRICK, Middle Tennessee State
University—Patients undergoing weight loss surgery frequently report
a mismatch between their new body shape and their perceived shape
(affecting such decisions as which chairs can hold them or whether
they can walk down the aisle in an airplane). Preliminary research was
conducted to determine what might influence changes in affordances
after changes in body shape. For an initial study using a method of
limits procedure, participants were asked to judge whether or not they
could fit through an aperture when facing forward or sideways or carrying
a large backpack. Participants were then asked to pass through
the aperture to determine the smallest gap through which they could
actually fit. Participants were slightly more accurate for facing forward
than for facing sideways or carrying a backpack. Additional
studies will investigate improvements to the methodology and how af-