S1 (FriAM 1-65) - The Psychonomic Society

Saturday Noon Posters 4090–4096
stepping on a treadmill, all of which produced a constant stepping rate
but differed in the physical turning rate of the body. Our findings confirm
that guidance is dominated by biomechanical information. However,
it is organized not simply from biomechanical information in
isolation but from co-occurring biomechanical and inertial information.
We conclude that the biomechanical and inertial systems have
evolved into an interconnected unit with enhanced perceptual acuity
through activation-dependent excitatory interactions.
(4090)
Visually Induced Steering Errors From Simulated Blowing Snow
Are Affected by Environmental Objects. ROGER LEW, BRIAN P.
DYRE, AARON POWERS, & FRANK YARBROUGH, University of
Idaho—Translating through laterally blowing snow creates nonrigid
transparent optical flow with two distinct foci of expansion (FOE) corresponding
to the snow and ground. Such optical flow induces illusory
perceptions of heading relative to the ground and produces systematic
steering errors, whose magnitude and direction depend on the
angle between the vectors defining the snow and observer movements.
At small angles (4º–8º), observers misperceive curvilinear movement
toward the snow FOE (attraction errors) and steer away from it. At
larger angles (>16º), observers misperceive curvilinear movement
away from the snow FOE (repulsion errors) and steer toward it. Here,
we examined whether randomly placed posts projecting from the
ground affect these steering errors. We found that the density of the
posts affected the angle at which errors of attraction cross over to errors
of repulsion, suggesting that the illusion may be influenced by the
magnitude of relative motion between the snow and environment.
(4091)
Seeing on Another World: Perceptual Challenges of Lunar Operations.
MARY K. KAISER & ALBERT J. AHUMADA, JR., NASA Ames
Research Center—The lunar environment provides different perceptual
affordances than does Earth. There are no ambient sounds or
scents. The suits that humans must wear to survive greatly attenuate
and alter tactile stimulation. Even the gravitational–inertial cues differ,
due to the lower gravity. Consequently, there is a heightened dependence
on visual cues; yet many of these are altered or compromised
as well. The absence of an atmosphere impacts illumination
conditions and distance cuing. Furthermore, current plans to conduct
operations near the lunar poles will result in low sun angles, exacerbating
problems associated with shadowing and glare. We will discuss
the challenges that these conditions will present to the human explorers,
and consider some possible mitigations and countermeasures.
• SPATIAL COGNITION •
(4092)
Spatial Distortions With Successively Flashed Stimuli. DIANA
BOCIANSKI, RWTH Aachen University, GISA ASCHERSLEBEN,
University of the Saarland, & JOCHEN MÜSSELER, RWTH Aachen
University—When observers are asked to localize the peripheral position
of a flashed probe with respect to a previously presented comparison
stimulus, they tend to judge it as being more toward the fovea than
the comparison stimulus is. Experiments revealed that the mislocalization
only emerges when comparison stimulus and probe are presented
successively, not when they are presented simultaneously. In addition,
the mislocalization decreases with larger interspaces between stimuli,
and it is reversed with stimulus onset asynchronies above 400 msec.
Findings are discussed as spatial effects of priming mechanisms.
(4093)
Recovering 3-D Structure From 2-D Images by Integrating Visual
and Haptic Inputs. BING WU, ROBERTA L. KLATZKY, & GEORGE
STETTEN, Carnegie Mellon University (sponsored by Roberta L.
Klatzky)—A 2-D figure translating behind a slit can be perceived but
appears distorted. We performed a 3-D analogue. By moving an imaging
transducer over a box, the subject viewed successive slices of a
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hidden virtual rod, displayed either at the haptically explored location
(via an augmented-reality visualization) or displaced to a remote LCD
that separated the visual and haptic inputs. The subject matched the
virtual rod’s pitch and/or yaw with a physical rod. When the virtual
rod tilted in only one dimension, subjects performed well with both
displays. However, when judging pitch and yaw together, and when visual
information was spatially incongruent with haptic, subjects made
large errors. These frequently took the form of near-correct magnitude
but reversed direction, suggesting that responses were based on discrete
codes. We suggest that when complex 3-D structure must be inferred
from 2-D images, displaced visual information interferes with
spatiotemporal integration.
(4094)
The Influence of Concurrent Verbal Working Memory Load on Spatial
Orientation in a Virtual Environment. JENNIFER E. SUTTON,
Brescia University College, & HOLLY M. CSIKOS & MARC F.
JOANISSE, University of Western Ontario—It has been suggested that
adults’ flexible use of both geometric and feature information in spatial
reorientation tasks is mediated by linguistic processing (Hermer-
Vazquez et al., 1999). However, some recent research has cast doubt on
whether linguistic processing is really necessary for feature use in such
tasks (Ratliff & Newcombe, 2005). In the present study, adult participants
performed a reorientation task in a virtual rectangular room that
had either four identical white walls (no-feature room) or three identical
white walls and one red wall (feature room). On some trials, participants
also performed either a concurrent verbal shadowing task or a
digit memory task. Neither of these concurrent tasks interfered with
participants’ use of the colored wall feature to reorient themselves.
However, verbal shadowing did interfere with the use of geometric cues
in the no-feature room, an effect not addressed in previous studies.
(4095)
Map Drawing Reveals Spatial Mental Model Development Following
Virtual Navigation. MARC M. SEBRECHTS, JASON SPITALETTA,
& JENNIFER MILES, Catholic University of America—This study
used detailed analysis of map drawing to examine development of spatial
mental models in a controlled virtual environment. Participants
followed a specified route through a virtual building, and drew a map
of that building following each trial. Video recording tracked the progression
of individual map drawings as well as the final product. Substantial
differences emerged in strategy, structure, and sequence of
map production. The data provide some support for the typical landmark,
route, survey sequence of acquisition, but also showed strong
distinctions between formation of specific route-based representations
and survey-like representations embedded in a more general
framework. Continuous tracking of drawing identified particular
characteristics of the participants’ models, including a tendency to use
route primacy and recency, the anchoring of elements around key
structural features, variation in the importance of orientation and
alignment, and shifting priorities between objects and paths.
(4096)
Mediation of Sexually Dimorphic Cognitive Task Performance by
Hormonal Contraceptives. WHITNEY WHARTON, University of
Wisconsin, Madison, ELLIOT HIRSHMAN, George Washington University,
PAUL MERRITT, Texas A&M University, Corpus Christi, &
SAMANTHA PARIS & LINDSAY DOYLE, George Washington
University—The present study investigated whether hormonal contraceptives
mediate performance on sexually dimorphic cognitive
tasks across the menstrual cycle in younger individuals. Visuospatial
tasks included the mental rotation, spatial orienting, and visual search
tasks. Recognition memory and digit span performance were also examined.
The results show the following. (1) The relation between
menstrual cycle phase and visuospatial performance is different in OC
users and nonusers. (2) Visuospatial performance is influenced by the
androgenic activity of OCs. Importantly, Yasmin users not only performed
more poorly on visuospatial tasks than did 2nd- and 3rd-