S1 (FriAM 1-65) - The Psychonomic Society

Papers 263–269 Sunday Morning
Task Switching
Regency ABC, Sunday Morning, 8:00–9:40
Chaired by Catherine M. Arrington, Lehigh University
8:00–8:15 (263)
Stimulus–Task Binding in Voluntary Task Switching: The Role of
Prior Experience in Task Choice. CATHERINE M. ARRINGTON
& RACHEL L. PAUKER, Lehigh University—Stimulus–task binding
has been hypothesized to underlie some performance deficits on
switch trials in task-switching paradigms. We examined the effect of
individual stimuli on task choice in a voluntary task-switching (VTS)
paradigm where subjects are allowed to choose which task to perform
on each trial. Subjects performed large/small or living/nonliving
judgments on single-word stimuli under instructions to perform the
tasks equally often in a random order. Stimulus–task binding was
measured as a match to the initial categorization of an item in all subsequent
presentations of that stimulus. When subjects voluntarily
choose the initial categorization, the probability of match to initial
was substantial (.669). This effect was reduced (.522), but still significant,
when the initial categorization was determined by the experimenter.
The roles of prior experience with a stimulus and stimulus
identity in VTS suggest that task choice is a complex process
involving interactions of internal and external factors.
8:20–8:35 (264)
Strategic Control Over Task-Set Inhibition. ULRICH MAYR, University
of Oregon, & STEPHAN STEGT, University of Bonn—We
(Mayr & Bell, 2006) recently suggested that rate of switching in a voluntary
switching situation depends on whether individuals adopt a
“continuous-flow” or a “discrete-event” strategy. Theoretically, the
discrete-event strategy is characterized by inhibition after each trial,
thereby clearing the slate for an unbiased choice of the next-trial task.
In Experiment 1, we instructed subjects to either treat trials as a stream
of interdependent stimulus–response instances or as distinct events.
As expected, discrete-event subjects showed higher switch rates. In
addition, they exhibited longer no-switch and faster switch RTs than
did continuous-flow subjects, which is consistent with the use of inhibition
to segregate consecutive events. In Experiment 2, we tested
the inhibition prediction directly, by assessing the effect of strategy on
the backward-inhibition effect (Mayr & Keele, 2000). As expected,
we found substantial backward inhibition after discrete-event, but
none after continuous-flow instruction. Thus, inhibition seems to be
under some strategic control.
8:40–8:55 (265)
Response Effects in Voluntary Task Switching. ANDRE VAN-
DIERENDONCK, JELLE DEMANET, & BAPTIST LIEFOOGHE,
Ghent University—In voluntary task switching, participants are free
to select the task to perform, as long as they perform both tasks an approximately
equal number of times and perform the tasks in a random
order. Previous research (Mayr & Bell, 2006) demonstrated an influence
of sequences of stimuli on this pattern of alternation. Following
this up, we investigated the role of response sequences by manipulating
the compatibility of the response layout in task selection and task
execution. We were interested in the effects of the intertrial interval
on the response used to indicate the subsequent task selection. Three
experiments demonstrated that task selection latencies were affected
by these response variations, whereas the task-repetition probabilities
and task selection randomness only varied with the intertrial interval.
These results show that while response effects influence task-level
processes, they do not come into play in the process of task selection.
9:00–9:15 (266)
Proactive and Concurrent Interferences in Task-Switching.
MYEONG-HO SOHN, E. ZITA PATAI, & REBECCA B. WELDON,
George Washington University—Cognitive control is required to minimize
the interference effect on the performance of the goal-relevant
41
task. In this study, we examined the effects of proactive and concurrent
interferences. The proactive interference occurs when the current
task is different from the most recent task. The concurrent interference
occurs when the current target is accompanied with a distractor.
Participants performed two perceptual classification tasks and two semantic
classification tasks in a task-switching paradigm. In general,
participants were more fluent with perceptual than with semantic
tasks. When switching between different tasks, the latency of semantic
tasks was slower when preceded by perceptual tasks. In addition,
the semantic tasks were performed slower when the concurrent distractor
was associated with another semantic task. The perceptual
tasks were not affected by the types of distractors or transitions. These
results suggest that the interference effect depends on the strength of
the relevant and irrelevant tasks.
9:20–9:35 (267)
Hierarchical Plans Can Produce Nonhierarchical Behavior. GOR-
DON D. LOGAN & DARRYL W. SCHNEIDER, Vanderbilt University—Hierarchical
plans structure behavior by dividing a set of tasks
into subsets and specifying which subset to perform at which time.
Usually, the sequence of tasks in the plan mirrors the sequence of
tasks the person performs—the plan says “do A, then B” and the person
does A then B—making it hard to determine whether the observed
evidence of hierarchical control reflects plan-level processing or tasklevel
processing. We separated these levels of processing by having
subjects memorize two task sequences and then perform a randomly
cued task at one of the serial positions in a sequence (e.g., “alpha 3”
meant “perform task three from list alpha”). Response times were
longer when subjects switched between sequences than when they repeated
sequences, indicating hierarchical plan-level processing. We
present a model that illustrates how structured plans control sequences
of responses that do not mirror the sequence in the plan.
Memory
Regency DEFH, Sunday Morning, 8:00–10:00
Chaired by Moshe Naveh-Benjamin
University of Missouri, Columbia
8:00–8:15 (268)
Is Older Adults’ Associative Memory Deficit Mediated by Age-
Related Sensory Decline? MOSHE NAVEH-BENJAMIN, ANGELA
KILB, & YOKO HARA, University of Missouri, Columbia—Numerous
studies show age-related decline in episodic memory. One of the
explanations for this decline is an associative deficit hypothesis,
which attributes part of older adults’ declining episodic memory performance
to their difficulties encoding and retrieving separate features
of episodes as cohesive entities (e.g., Naveh-Benjamin, 2000).
Here, we evaluate the degree to which this deficit is partially mediated
by sensory loss associated with increased age. In two experiments,
young adults were presented with visually and auditorily degraded
word pairs. Their memory for both the components and the
associations of these degraded pairs was then tested using word and
associative recognition tests, respectively. We also used groups of
older adults with nondegraded stimuli. The results and their theoretical
implications will be discussed.
8:20–8:35 (269)
Ventromedial Prefrontal Damage Impairs Source but Not Associative
Memory. ELISA CIARAMELLI, Rotman Research Institute, &
JULIA SPANIOL, Ryerson University (read by Julia Spaniol)—Both
associative recognition (AR) and source memory (SM) are thought to
capture episodic binding. However, whether these tasks tap the same
cognitive and neural systems is unclear. Here, we show a dissociation
between AR and SM in patients with lesions in ventromedial prefrontal
cortex. Thirteen patients, including 6 with spontaneous confabulation,
and 13 controls studied picture–word pairs and received
an old–new recognition test. Lures included rearranged pairs (studied