S1 (FriAM 1-65) - The Psychonomic Society

Friday Evening Posters 3106–3111
consistency after 6 months was 100%. Skin conductance responses
(SCRs) were monitored while we left each subject alone in a room so
they wouldn’t need to “fake” specific emotional expressions to convince
us of their authenticity. A hidden camera videotaped their expressions
evoked by different textures and the tapes were subsequently
analyzed by blinded researchers to rule out confabulation. Evaluators’
ratings significantly correlated with the valency of synesthetes’ subjective
reports, and SCR was significantly enhanced for negative synesthetic
emotions. We suggest that this effect arises from increased crossactivation
between S2 somatosensory cortex and insula for “basic”
emotions and fronto-limbic hyperactivation for more subtle ones.
(3106)
Cross-Modal Comparisons of Time Intervals Presented or Not
Presented in Sequences. SIMON GRONDIN, University of Laval, &
J. DEVIN MCAULEY, Bowling Green State University—In four experiments,
participants were presented with two sequences, each consisting
of 1 or 4 intervals (marked by 2 or 5 signals), and were asked
to indicate whether the interval(s) of the second sequence was (were)
shorter or longer than the interval(s) of the first. On each trial, the
standard sequence, which could occur first or second, delineated a
fixed 500-msec interval, whereas the comparison sequence delineated
a variable interval that was 500 ± 15, 45, 75, or 105 msec. Markers in
Sequence 1 and Sequence 2 were, respectively, sounds and flashes
(Experiment 1), flashes and sounds (Experiment 2), both flashes (Experiment
3), and both sounds (Experiment 4). In general, the results
showed that discrimination was better (1) when four intervals were
presented, rather than one (especially in Sequence 2); (2) when the
standard interval(s) was (were) presented before the comparison interval(s);
and (3) when sequences were marked by sounds, rather than
by flashes.
• SPATIAL UPDATING •
(3107)
Path Integration and Spatial Updating in Humans: Behavioral Principles
and Underlying Neural Mechanisms. THOMAS WOLBERS &
MARY HEGARTY, University of California, Santa Barbara, CHRIS-
TIAN BUECHEL, University Medical Center, Hamburg-Eppendorf,
& JACK LOOMIS, University of California, Santa Barbara—Path integration,
the sensing of self-motion for keeping track of changes in
orientation and position, constitutes a fundamental mechanism of spatial
navigation. Here, we show that humans can reliably estimate selfmotion
from optic flow in virtual space, which relied upon the dynamic
interplay of self-motion processing in area MST, higher-level
spatial processes in the hippocampus, and spatial working memory in
medial prefrontal cortex. A subsequent eye movement study revealed
that when the positions of external objects have to be updated simultaneously,
humans do not simply track remembered locations by
means of saccadic eye movements. Instead, incoming self-motion
cues are integrated with stored representations in the precuneus to enable
online computation of changing object coordinates and to generate
motor plans for potential actions in dorsal premotor cortex.
These results will be discussed in the context of an emerging theoretical
model of navigational learning.
(3108)
Where Am I? Updating Nested Spatial Memory Learned From Different
Sources. A. REYYAN BILGE & HOLLY A. TAYLOR, Tufts
University—People mentally update environment locations relative to
their own position as they move, a process called spatial updating.
Wang and Brockmole (2003) found that when learning nested environments
from direct experience, the more immediate (or proximal)
surrounding (room) received updating priority, whereas the remote
one (i.e., campus) required more effortful updating. The present work
examined nested updating after map learning. Participants learned locations
within a room nested within a campus either through direct experience
or via maps. After learning both environments, they updated
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their location with respect to one of the environments and then completed
tasks assessing knowledge of both environments. The results
suggested that learning format selectively favors different levels of a
nested environment. People more accurately represented the proximal
environment (room) following navigation, whereas they more accurately
represented the remote environment (campus) after map learning.
These results have implications for best practice in representing
environments on different scales.
(3109)
Knowledge Updating on the Basis of Learning From Spatial Actions
and Spatial Language. ALEXANDRA PETERS & MARK
MAY, Helmut Schmidt University (sponsored by Mark May)—Do spatial
actions and spatial language lead to functionally equivalent or to
functionally distinct types of spatial representation? In two experiments,
we used real and imagined perspective switches to examine
this question. Blindfolded participants were asked to learn object locations,
either by exploring the locations with a cane (spatial action)
or by hearing verbal descriptions (spatial language). In Experiment 1
with bodily switches (i.e., self-rotations between 0º and 180º), pointing
latencies were longer after language than after action learning, especially
for the more difficult testing perspectives (45º and 135º). In
Experiment 2 with imagined switches to the same perspectives, spatial
disparity between real and imagined perspective had a significant
effect on latencies, both learning conditions being similarly affected.
Implications of these findings for single- versus dual-code conceptions
of the underlying spatial representations and processes are
discussed.
(3110)
The Effect of Active Selection in Path Integration. XIAOANG WAN,
RANXIAO FRANCES WANG, & JAMES A. CROWELL, University of
Illinois, Urbana-Champaign (sponsored by Ranxiao Frances Wang)—
Many species can integrate information of self-motion to estimate
their current position and orientation relative to the origin, a phenomenon
known as path integration. We used a homing task in virtual
hallway mazes to investigate the effect of active selection/planning in
path integration. Participants traveled along hallways and attempted
to directly return to the origin upon seeing a golden apple. Half of the
participants freely decided the direction and distance of each hallway
by themselves (completely free selection condition). The other half
followed the identical outbound pathways selected by their counterparts
(passive following condition). The two groups received the same
perceptual and motor information but differed in the voluntary selection
of the path structure. We found no overall facilitation effect of active
selection on homing performance, possibly due to the trade-off
between the advantage of planning and the cost of increased working
memory load and task complexity in the active selection condition.
(3111)
Intrinsic Reference Direction in Sequentially Learning a Layout.
XIANYUN LIU & WEIMIN MOU, Chinese Academy of Sciences, &
TIMOTHY P. MCNAMARA, Vanderbilt University (sponsored by
Weimin Mou)—Mou, Liu, and McNamara (2007) showed that preferred
directions in pointing judgments (e.g., “Imagine you are standing
at X, facing Y, please point to Z”) were consistent with the sequence
that participants used to learn locations of objects, suggesting
that the learning sequence may determine the spatial reference direction
in memory. In this project, participants learned a layout of 7 objects
with a symmetric axis different from the learning view. In Experiment
1, the objects’ locations were illustrated by circular disks
that were always presented during learning, and the objects were presented
sequentially in a random order. In Experiment 2, the disks were
removed and the objects were presented sequentially along the symmetric
axis. The results showed that the preferred heading was determined
by the symmetric axis in Experiment 1 but by the learning direction
in Experiment 2. These results suggest that spatial reference
directions are established before learning sequence.