S1 (FriAM 1-65) - The Psychonomic Society

Sunday Morning Papers 284–289
Based on evidence from spoken language corpora, Clark and Fox Tree
(2002) hypothesized that the fillers “um” and “uh” represent signals
of anticipated major and minor delay, respectively. But if they are genuine
signals of delay, then they should show effects on the listener.
Two mouse-tracking experiments supported this prediction. Listeners
expected a speaker to refer to something new following an “um” but
not following an “uh,” and only when “um” was followed by a sufficiently
long pause (Experiment 1). Furthermore, this expectation was
based on active perspective taking rather than on a learned association
between a particular pattern of disfluency and new information:
Listeners expected information that would be new for the current
speaker, even though that information was old for them (Experiment
2). These findings suggest that “uh” and “um” are metacognitive
collateral signals that draw listeners’ attention to a speaker’s cognitive
state.
Movement, Distance, and Depth Perception
Seaview, Sunday Morning, 8:00–9:20
Chaired by Maggie Shiffrar, Rutgers University, Newark
8:00–8:15 (284)
Facing Apparent Motion: A Translating Eyeball Illusion. SONGJOO
OH & MAGGIE SHIFFRAR, Rutgers University, Newark (read by
Maggie Shiffrar)—Traditional models of the human visual system assume
that all classes of visual images are initially analyzed in the same
way. From this perspective, the same processes are employed when observers
view crashing waves and smiling children. We tested this assumption
by investigating whether face perception changes motion
perception. In psychophysical studies, we tested the perception of classic
apparent motion phenomena. Wertheimer (1912) initiated Gestalt
psychology with the finding that two sequentially presented static dots
can appear as one translating dot. When these two dots are positioned
in the eye sockets of an upright face, the perception of translation stops.
Face processing also impacts a modified Ternus (1926) display such
that dots that appeared to move independently instead appear to move
together in as eyes in a face. These results suggest that the visual analysis
of facial motion differs from other motion analyses.
8:20–8:35 (285)
Why Do Moving Objects Interfere With the Visibility of Stationary
Ones? JUDITH AVRAHAMI & OREN FLEKSER, Hebrew University—The
fact that moving objects interfere with the visibility of stationary
ones has been known for a long time (Bonneh, Cooperman, &
Sagi, 2001; Grindley & Townsend, 1966; MacKay, 1960), but its
cause is still in dispute. To achieve some insight into the phenomenon
the time required for detecting a gradually appearing Gabor stimulus
on the background of moving dots was measured. The direction and
speed of the dots and the orientation and spatial frequency of the
Gabor were manipulated. When its spatial frequency was high, the
Gabor stimulus was harder to detect when its orientation was orthogonal
to the direction of the moving dots than when parallel; the difference
increased with faster dots. Surprisingly, the opposite was true
when the spatial frequency of the Gabor was low. These results provide
clues as to what the eye must be doing when watching moving
objects and when perceiving stationary ones.
8:40–8:55 (286)
Testing Two Accounts of a Failure of Perceptual Separability.
STEPHEN C. DOPKINS, George Washington University—In the
complex distance task, the stimuli vary on two spatial dimensions and
the error rate for distance judgments regarding one dimension depends
on the interstimulus distance on both dimensions. According to
the mean-shift integrality (MSI) account, this phenomenon reflects
the mental representation of the stimuli; the mean of the distribution
for a stimulus on each dimension of the representation depends on the
level of the stimulus on both spatial dimensions. According to the derived
distance (DD) account, the phenomenon reflects the distance es-
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timation process; the distance between a pair of stimuli on a given dimension
is derivative of the distance between them on both dimensions—distance
on a given dimension can only be assessed to the degree
that the dimension’s scale is made greater than the scale of the
other dimension. The DD account fit the data from several experiments
better than the MSI account did.
9:00–9:15 (287)
A Substantial Genetic Contribution to Stereoscopic Depth Judgments
Further Than Fixation. JEREMY B. WILMER & BEN-
JAMIN T. BACKUS, University of Pennsylvania—One in three individuals
is blind to some range of stereoscopic depth for briefly
presented stimuli (1). We tested precision of depth estimation from
stereopsis in 65 identical and 35 fraternal twin pairs using a recently
developed test (2). Precision for each individual was calculated as the
increment in disparity that caused an increment in reported depth on
75% of trials. Using structural equation modeling we estimated the influences
of genetic and environmental factors on stereoscopic precision.
Almost all reliable individual variation in “far” precision (beyond
fixation) was attributable to genes (57%, 38%–70%*), but genes
did not contribute to individual variation in “near” precision (closer
than fixation; 0%, 0%–26%*). Thus specific genetic markers may
correlate with far stereopsis and therapeutic interventions may be
most successful if they target near stereopsis. *±1SE. (1) Richards, W.
(1970) Experimental Brain Research, 10, 380-388. (2) van Ee, R., &
Richards, W. (2002) Perception, 31, 51-64.
9:20–9:35 (288)
Extremal Edges and Gradient Cuts: New Cues to Depth and Figure–
Ground Perception. STEPHEN E. PALMER & TANDRA GHOSE,
University of California, Berkeley—Extremal edges (EEs) and gradient
cuts (GCs) are powerful cues to depth and figure–ground organization
that arise from shading and texture gradients, where convex,
smoothly curved surfaces occlude themselves (EEs) or are occluded by
other surfaces (GCs). Ecological constraints imply that the EE side of
the shared edge should be seen as closer and figural, and experimental
evidence shows that they are. Indeed, EEs readily dominate even
combinations of well-known classical figure–ground cues (e.g., size
and convexity). The GC side of a shared edge tends to be seen as a farther/ground
surface. The strength of GC effects depends strongly on
the relation between the shared edge and the gradient’s equiluminance
contours, including the angle between them and the alignment of inflection
points along the edge with luminance minima and maxima
along the shading gradient. Together they strongly determine the perception
of relative depth across an edge and figure–ground assignment.
Picture Processing and Imagery
Shoreline, Sunday Morning, 8:00–10:00
Chaired by James R. Brockmole, University of Edinburgh
8:00–8:15 (289)
Prioritizing New Objects for Eye Fixation in Scenes: Effects of
Object–Scene Consistency. JAMES R. BROCKMOLE & JOHN M.
HENDERSON, University of Edinburgh—Recent research suggests
that new objects appearing in real-world scenes are prioritized for eye
fixations and by inference, for attentional processing. We examined
whether semantic consistency modulates the degree to which new objects
appearing in a scene are prioritized for viewing. New objects
were added to photographs of real-world scenes during a fixation
(new object with transient onset) or during a saccade (new object
without transient onset). The added object was either consistent or inconsistent
with the scene’s meaning. Object consistency did not affect
the efficacy with which transient onsets captured attention, suggesting
that transient motion signals capture attention in a bottom-up manner.
Without a transient motion signal, the semantic consistency of the
new object affected its prioritization with new inconsistent objects
fixated sooner than new consistent objects, suggesting that attention