Abstracts 2005 - The Psychonomic Society

Posters 4001–4007 Saturday Noon
POSTER SESSION IV
Sheraton Hall, Saturday Noon, 12:00–1:30
• 3-D AND MOTION PERCEPTION •
(4001)
Visual Characteristics of Biological Motion: Investigations With
a New Stimulus Set. JOHN A. PYLES, EMILY D. GROSSMAN, &
DONALD D. HOFFMAN, University of California, Irvine (sponsored
by Myron L. Braunstein)—Biological motion research typically uses
point-light animations depicting highly constrained and familiar
human movement. To investigate the visual characteristics critical for
invoking perception of biological motion, we have created a new stimulus
set based on computer generated creatures that possess novel, coherent
motion and appear biological. Our results from a perceived animacy
rating experiment confirm that the creatures are perceived as
alive. In a second experiment, we measured noise tolerance thresholds
for upright and inverted human, animal, and creature animations. Inversion
of point-light animations reduces sensitivity to biological motion
and is thought to reflect configural processing. We found a reduced
inversion effect for creature and animal animations, relative to
the human sequences. Our results provide evidence for the importance
of motion in perceived animacy and of familiarity and body structure
in biological motion perception.
(4002)
Is Action Observation Synonymous With Action Prediction?
GERTRUDE RAPINETT, Max Planck Institute for Human Cognitive
and Brain Sciences, GÜNTHER KNOBLICH, Rutgers University,
Newark, MARGARET WILSON, University of California, Santa Cruz,
& WOLFGANG PRINZ, Max Planck Institute for Human Cognitive
and Brain Sciences—When we observe someone performing an action,
we can predict, to some extent, the outcome of the observed action.
Action prediction may be a corollary of the involvement of the
observer’s action system during the perception of actions performed
by conspecifics (Kilner, 2004). The aim of these experiments was to
identify which attributes of an action enable an observer to anticipate
the future consequences of actions. More specifically, we investigated
whether the kinetics of an action (dynamic/static), the congruency between
the action grip and the target object (power/precision), and the
functional relationship between the action and the target object (related/
unrelated) effect the accuracy of prediction. Participants were presented
with images from different points in the movement trajectories
and were required to predict the outcome. Kinetic information modulated
most strongly the accuracy of prediction. Possible mechanisms
involved in action prediction based on the observer’s action system are
discussed.
(4003)
Implicit Action Encoding Influences Personal Trait Attribution.
PATRIC BACH, CHARLES E. LEEK, & STEVEN P. TIPPER, University
of Wales, Bangor—To-be-executed actions and observed actions
activate overlapping action representations. A consequence of this
vision–action matching process is that producing actions one simultaneously
observes will be easier than producing different actions. For
example, when observing another person kick a ball, a foot response
to identify a stimulus will be faster than a response with a finger. In
contrast, observing a person press a key will facilitate a finger response
relative to a foot response. We demonstrate that compatibility between
perceived actions and executed responses can also influence the personality
traits attributed to the viewed person. These vision–action–
personality effects can be observed both with an explicit rating measure
and when measured implicitly with a priming procedure.
(4004)
Improving Distance Estimation in Immersive Virtual Environments.
ADAM R. RICHARDSON & DAVID WALLER, Miami University
(sponsored by Yvonne Lippa)—It is well known that distances are un-
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derestimated in computer simulated (virtual) environments, more so
than in comparable real-world environments. Three experiments examined
observers’ ability to use explicit (Experiments 1 and 2) or implicit
(Experiment 3) feedback to improve the accuracy of their estimates
of distance in virtual environments. Explicit feedback (e.g.,
“You estimated the distance to be 2.4 meters, the actual distance was
4.5 meters”) improved the accuracy of observers’ distance estimates,
but only for the trained type of distance estimate (egocentric or exocentric)
and the trained type of response (direct or indirect blindfolded
walking). Interestingly, brief closed-loop interaction with the virtual
environment (i.e., implicit feedback) also resulted in near-veridical
distance estimation accuracy.
(4005)
Misperceived Heading and Steering Errors Occur When Driving
in Blowing Snow. BRIAN P. DYRE & ROGER LEW, University of
Idaho—Driving through blowing snow creates a transparent optical
flow with two foci of expansion (FOEs). Previous research showed
that such optical flow produces systematic errors in judgments of the
direction of heading when the FOEs are misaligned (nonrigid). Here,
we examined whether these errors generalize to control of heading in
a more realistic simulation: driving across a textured ground plane
through blowing snow. Participants were instructed to steer a simulated
vehicle such that they maintained a straight path while crosswinds
caused snow to move at varying angles (0º–64º) relative to the
initial direction of translation. For nonzero angles, a pattern of systematic
steering errors was found where smaller angles biased steering
away from the FOE defined by the snow, and larger angles biased
steering toward the snow’s FOE. These results show that misperception
of heading from nonrigid transparent optical flow can cause systematic
errors in the steering of simulated vehicles.
(4006)
Perceptual Learning and the Visual Control of Collision Avoidance.
BRETT R. FAJEN, Rensselaer Polytechnic Institute—What distinguishes
experts from novices performing the same perceptual–motor
task? The superior performance of experts could be attributed, in part,
to a form of perceptual learning known as perceptual attunement. In
this study, perceptual attunement was investigated using an emergency
braking task in which participants waited until the last possible moment
to slam on the brakes. Biases resulting from the manipulation of
sign radius and initial speed were used to identify the optical variables
upon which participants relied at various stages of practice. I found
that biases that were present early in practice diminished or were eliminated
with experience and that the optical variables to which observers
became attuned depended on the range of practice conditions
and the availability of information. Perceptual attunement resulting
from practice on emergency braking transferred to normal, regulated
braking, suggesting that perceptual attunement plays an important
role in learning to perform a visually guided action.
• MUSIC COGNITION •
(4007)
Repetition Priming in Music Performance. SEAN HUTCHINS &
CAROLINE PALMER, McGill University—Four experiments addressed
the role of implicit memory in a music production task. Singers heard
short melodies of predetermined length and sang the final tone as
quickly as possible. We manipulated whether the final tone (target)
was a repetition of a previous melodic tone (prime) and the distance
(intervening tones) between prime and target tones. Experiment 1 manipulated
prime–target distance along with stimulus length, whereas
Experiment 2 manipulated prime–target distance independently of
stimulus length. Experiments 3 and 4 also manipulated the stimulus
rate (tempo). Experiment 1 showed a significant benefit of repetition
priming on singers’ response latencies. Experiment 2 showed a benefit
for repetition at shorter prime–target distances and a benefit for
expected (tonic) endings over less expected (nontonic) endings. Re-