Abstracts 2005 - The Psychonomic Society

Posters 5100–5106 Saturday Evening
the activity of the system controlling intention-based actions results
in action–effect (ideomotor) learning.
(5100)
Planning Tool Actions. CRISTINA MASSEN & WOLFGANG PRINZ,
Max Planck Institute for Human Cognitive and Brain Sciences—In our
experiments, we investigated the planning and representation of tool actions.
Results from previous work suggest a subordinate role of the
movement itself in the representation of tool actions, and in this study,
we focus on the relative roles of the transformation and the intended effect
of the movement. Subjects were required to plan lever actions displayed
on a computer screen and indicated by buttonpresses how (in
terms of direction and amplitude) to move the end of a lever to produce
an intended effect, given a specific center of rotation of the lever (transformation).
In a tool-switching paradigm, subjects either switched between
two transformations (A and B; Condition 1) in successive tool actions
or switched between two effects (A and B; Condition 2). Results
point toward a dominant role of the transformation in planning tool actions
and are discussed with respect to the ideomotor theory of action.
(5101)
Tool Transformation and Fitts’s Law: The Influence of Extracorporeal
Space. MARTINA RIEGER & WOLFGANG PRINZ, Max Planck
Institute for Human Cognitive and Brain Sciences—Does Fitts’s law
hold when different transformations between movement space and visual
space are introduced? In Experiment 1, participants carried out
continuous vertical reversal movements. Movement amplitude (12 cm)
and target width (0.4 cm) and, therefore, index of difficulty (5.91)
were equal for all conditions. Nine different gain conditions were conducted
in different blocks (1.8, 1.6, 1.4, 1.2, 1.0, 0.8, 0.6, 0.4, 0.2).
Movements with higher gain were slower and had lower peak velocity
than did movements with lower gain. According to Fitts’s law,
movement times should be equal in all conditions. The results therefore
indicate that extracorporeal space has an effect on movement
kinematics and that Fitts’s law does not hold across different transformations
between movement space and visual space. Experiment 2
showed that the effects of external space are more pronounced with
high indexes of difficulty and large gains.
(5102)
Does Compatibility Interference Require Similar Response Actions?
MATTHEW WIEDIGER & LISA R. FOURNIER, Washington State
University—Previous research shows that planning and withholding
an action to a stimulus (X1) can delay the response to a second stimulus
(X2), if X2 is response compatible (requires the same response
hand) with X1 (compatibility interference, CI). According to Stoet
and Hommel (1999), CI occurs because of an overlap in response
codes (e.g., same hand) between X1 and X2. However, we found that
CI did not occur when X1 required an identity-based response and X2
required an ego-location–based response. In this case, perhaps the
motor actions required for X1 and X2 were too dissimilar or response
execution to X2 was too long to detect CI. The present study investigated
whether the failure to find CI for ego-location–based responses
was due to either of these factors. Results will be discussed in terms
of their implications for the code occupation hypothesis originally
proposed by Stoet and Hommel (1999) to account for CI.
(5103)
Human Rotational Preference and Behavioral Activation System
Sensitivity. DAVID A. ABWENDER & MIKE J. PUSATERI, SUNY,
Brockport (sponsored by Stuart Appelle)—Freely ambulating animals,
including humans, preferentially turn in the direction contralateral to
the brain hemisphere with greater tonic dopamine activity. Using 64
female and 25 male undergraduate participants, we investigated
whether rotational preference (RP) predicts behavioral activation system
(BAS) sensitivity, a behavioral disposition thought to be partly
mediated by left-hemisphere dopamine pathways. RP was assessed by
having participants move about a room in response to tones emanat-
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ing from speakers placed against the four walls. BAS sensitivity was
significantly higher among males with left RP and lower among males
with right RP but was unrelated to RP among women, presumably because
ovarian hormone fluctuation lowers RP assessment reliability.
Conclusion: Lower left- than right-hemisphere tonic dopamine release,
producing left RP, permits higher amplitude left-hemisphere
phasic firing bursts that yield high BAS sensitivity; higher left tonic
dopamine release, producing right RP, precludes high amplitude phasic
bursts, thus diminishing BAS sensitivity.
(5104)
Unintentional Movements During Action Observation: Copying or
Compensating? NATALIE SEBANZ & MAGGIE SHIFFRAR, Rutgers
University, Newark—People often unintentionally mimic others’ actions.
However, compensatory movements have been reported for situations
where actions that are inconsistent with the actor’s goal are observed.
The aim of the present study was to investigate systematically
when unintentional imitational and compensatory movements are
made. Participants were shown movies of a person balancing on a
foam roller. Their task was to indicate how likely they thought it was
that the actor would reach the end of the foam roller. The movies
showed the actor from the front and back. Using a motion capture system,
we measured unintentional movements during action observation.
Participants had a strong tendency to imitate the observed movements
when the actor was seen from the front. Compensatory movements occurred
when the actor was seen from the back. These findings suggest
that motor responses are mediated by the spatial relationship between
the observer and the actor.
(5105)
Dyslexic Adults’ Eye Movement Control During Reading and Visual
Tracking. ROBERT A. KACHELSKI, SINEEPORN CHATTRAKUL-
PONG, TERRI L. ENTRICHT, KRISTEN B. GAYNOR, MARGARET
R. JUDIN, & ROSEMARY LOKKO, Agnes Scott College—Currently,
most theoretical accounts of developmental dyslexia emphasize a
phonological processing deficit that makes decoding written words
into their constituent sounds difficult for dyslexics. However, some researchers
have found evidence of poor eye movement control that may
be an additional problem for at least a subset of those with dyslexia.
Because these findings have been controversial, the purpose of our research
was to determine whether dyslexics do, in fact, exhibit poor eye
movement control when compared with normal readers. We used an
eyetracking system to record dyslexic and control participants’ eye
movements as they completed both reading and visual-tracking tasks.
Results are presented comparing the two groups on variables relevant
to the control of eye movements, such as fixation accuracy and the
percentage of regressive eye movements, as well as variables relevant
to reading performance and phonological processing.
(5106)
The Effect of a Concurrent Task on Gait Performance in Children
With Developmental Coordination Disorder. RONG-JU CHERNG,
LING-ING LIANG, & JENN-YEU CHEN, National Cheng Kung University,
& CATHERINE L. PURDOM & LAURA M. TUTTLE, Agnes
Scott College (sponsored by Jenn-Yeu Chen)—Thirteen children (10
boys, 3 girls; ages 4–6 years) with developmental coordination disorder
(DCD) and 26 age- and gender-matched normal children were recruited
to examine the effect of a concurrent task on walking performance
under different task types (cognitive vs. motoric) and different
difficulty levels (easy vs. hard). Each child performed (1) free walking,
(2) walking while carrying an empty tray, (3) walking while carrying
a tray with seven marbles in it, (4) walking while repeating a
group of digits forward, and (5) walking while repeating the digits
backward. Walking performance was affected by the concurrent task
in DCD more than in normal children. Greater task difficulty increased
the dual-task cost in DCD children more than in normal ones.
However, the above patterns held true only when the concurrent task
was motoric. The cognitive task also affected the walking perfor-