S1 (FriAM 1-65) - The Psychonomic Society

Thursday Evening Posters 1021–1027
(SOAs). In Task 2, we varied the compatibility between the stimuli and
the intended (to-be-produced) action effects as well as the required transformation
of action effects into the responses. We found an inverted
Simon effect only with a long SOA, but an influence of the effect–
response transformation with all SOA levels. These results suggest that
at least two processes underlie the inversion of the Simon effect.
(1021)
What Is So Hard About Bimanual Coordination? Evidence for Conceptual
Interactions Between Bimanual Responses. KIMBERLY
HALVORSON, TANA TRUELOVE, & ELIOT HAZELTINE, University
of Iowa, & SIAN L. BEILOCK, University of Chicago (sponsored
by Sian L. Beilock)—Dual-task costs are robust when both tasks require
manual responses, and RTs are usually longer when the two responses
must be made with different hands than with the same hand
(Hazeltine et al., in press). In contrast, expert typists prefer letter
dyads that, if typed, would produce the least motor interference (i.e.,
are produced with different hands), while novice typists show no preference
(Beilock & Holt, 2007). We compared unimanual and bimanual
keypresses to examine how task representations affect bimanual
coordination. Expert typists saw two stimuli each indicating a single
keypress on a computer keyboard. With spatially compatible stimuli,
participants were slower when the two responses required different
hands. However, when letters corresponding to the keys on the keyboard
were used as stimuli, no bimanual costs were observed. The results
suggest that bimanual costs emerge from conceptual codes and
provide a glimpse into the central representations underlying discrete
RT tasks.
(1022)
Interhand Coordination Across Age. ROBERT M. KOHL, RAY-
MOND W. MCCOY, & CRYSTAL M. RADER, College of William &
Mary—There is much evidence to indicate that interhand coordination
is temporally/spatially linked during maximal (speed) conditions.
This linkage was investigated across age. Young adults (M = 19.7
years) and elders (M = 78.2 years) were compared during responses
in which their hands moved maximally/simultaneously the same distance
(28 cm) while one hand negotiated a 20- or 2-cm barrier. The
results indicated that young adults were significantly faster (M, SEM)
then elders in dual-handed movement time (52 msec, 11 msec), peak
velocity (.26 m/sec, .036 m/sec), and time to peak velocity (47.9 msec,
6.8 msec) but similar in dual-handed reaction time and peak height.
However, all relative barrier and nonbarrier hand comparisons of dependent
variables produced very similar results across age, illustrating
a strong hand linkage. Hence, these results indicated that an increase
in age negatively impacted maximal dual-handed responses but
did not impact the linkage of interhanded coordination.
(1023)
Coordination Strategies in Unimanual Circling Movements. SAN-
DRA DIETRICH, MARTINA RIEGER, & WOLFGANG PRINZ,
Max Planck Institute for Human Cognitive and Brain Sciences (sponsored
by Martina Rieger)—To investigate the coordination of unimanual
movements with external events, we used a circling task that
required participants to coordinate hand movements with a clockwise
circling stimulus. We dissociated the actual movement from its effect by
means of transformed feedback. This was done to determine whether
coordination takes place between movement and stimulus or between
movement effect and stimulus. Stimulus and effect were presented
next to each other (Experiment 1) or within each other (Experiment 2).
Additionally, we varied stimulus–effect relation (symmetric/parallel)
and movement phase (in-phase/anti-phase). The results indicate that
the external movement effect is more important for its coordination
with external events than is the movement itself. However, whereas for
easy tasks visual feedback seems to suffice, more complex tasks additionally
seem to integrate proprioceptive feedback. We argue that
feedback from the actual movement and its external effect are merged
to allow optimal performance.
54
• COGNITIVE CONTROL •
(1024)
Tracking Objects of Conflict Through Episodic Memory. MICHIEL
M. SPAPÉ & BERNHARD HOMMEL, Leiden University (sponsored
by Gezinus Wolters)—When people are required to respond with the
right to a stimulus appearing left, they are slower than when features
of perception and action correspond. Such effects can drastically
change and even reverse after noncorresponding trials, which is typically
understood to be caused by adapting to conflict. Measuring sequences
of conflict, however, inexorably means measuring patterns of
stimulus and response repetition. Performance costs are often observed
when repeating a stimulus but alternating a response, since the
previously integrated features overlap with the newly required binding.
To disentangle these two confounded effects, we hypothesized
that when a stimulus display is gradually changed between two trials,
the alternated feature should look as if it were repeated. Thus, by employing
concepts from object-based attention and multiple object
tracking, we show that feature integration may better account for sequential
Simon effects than for conflict adaptation.
(1025)
Is Voluntary Task Switching Influenced by Individual Differences in
Executive Control? KARIN M. BUTLER & CHRISTINA WEYWADT,
University of New Mexico, & CATHERINE M. ARRINGTON, Lehigh
University—This study investigated the ability to switch between
tasks in a voluntary task switching (VTS) procedure as it relates to
performance on working memory capacity measures. VTS requires
participants to initiate task choice rather than rely on an external cue,
allowing for a measure of switch probability in addition to switch
costs (Arrington & Logan, 2005). We examine relationships among
switch probability, switch cost, and working memory capacity measures.
The influence of internal control was assessed by manipulating
the time available to instantiate the task set, and the influence of external
information on task choice was manipulated by varying the
onset times of possible targets. The effects of executive control abilities
on task choice and switch costs will be discussed in relation to
factors influencing task selection and performance in VTS.
(1026)
Inducing Exaggerated Proactive Interference With Transcranial
Magnetic Stimulation. A. CRIS HAMILTON, ROY H. HAMILTON,
H. BRANCH COSLETT, TAMARA BOCKOW, & SHARON L.
THOMPSON-SCHILL, University of Pennsylvania—Neuroimaging
and neuropsychological data indicate that the left inferior frontal
gyrus (LIFG) is important for the resolution of proactive interference
(PI) in working memory. We used brief 300-msec trains of 10-Hz
rTMS to demonstrate that disruption of LIFG is causally involved in
resolving PI. Healthy subjects performed a probe recognition task
(Monsell, 1978) that reliably elicits PI (measured by response time
and accuracy). A list of three words was presented followed by a probe,
and subjects indicated whether the probe appeared in the list. PI was
elicited by manipulating the recency of probes. Consistent with previously
reported TMS data using this task (Feredoes et al., 2006), we
found greater effects of PI when TMS was applied to LIFG, and this
effect was apparent only in subjects’ accuracy. TMS did not influence
accuracy on positive trials, suggesting that effects of TMS to LIFG
were specific to trials that elicit PI.
(1027)
Task-Set Inhibition in Chunked Task Sequences. DARRYL W.
SCHNEIDER, Vanderbilt University (sponsored by Gordon D. Logan)—
Plans give structure to behavior by specifying whether and when different
tasks must be performed. A task sequence is an example of a plan
that can be represented at two levels: a sequence level and a task level.
In the present study, the relationship between chunking (a sequence-level
process) and task-set inhibition (a task-level process) was investigated
to determine whether within-chunk facilitation reduces the n�2 repeti-