S1 (FriAM 1-65) - The Psychonomic Society

Friday Noon Posters 2048–2054
ing training, the comparison response alternatives were always presented
following remember (R) cues, but never presented following
forget (F) cues. During testing, accuracy was significantly poorer on
F-cued trials than on R-cued trials. A choose-short bias was observed
at extended delays on both R-cued and F-cued trials. However, increasing
the duration of the R cues and F cues produced a choose-long
bias, indicating that rats responded to comparisons on the basis of the
combined duration of the sample and the postsample cue. This is the
first demonstration of a directed forgetting effect for event duration
memory in rats.
(2048)
Can Big Brown Bats Integrate Their Visual and Echoic Sensory
Systems? CAROLINE M. DELONG & JAMES A. SIMMONS, Brown
University—Big brown bats echolocate by emitting wideband frequencymodulated
sonar sounds and processing the echoes that return to their
ears. Little is known about their ability to integrate their echolocation
system with their visual system during object discrimination tasks. In
this experiment, bats were presented with a two-alternative forced
choice task in which the stimuli were a one-cylinder monopole target
(negative stimulus) and a two-cylinder dipole target (positive stimulus).
In the training phase, the stimuli were painted white and the task
was done in dim light so that the bats could use both echolocation and
vision. In the testing phase, the stimuli were presented in two unimodal
conditions (echolocation only and vision only) and one bimodal condition
in which one cylinder of the dipole target was presented visually
and the other echoically. If the bats succeed in the bimodal condition,
it implies that they can integrate these two sensory systems.
(2049)
Ultrasonic Vocalizations With Dorsal Stimulation in Rat Pups.
CHRISTOPHER WILSON, JEFFREY S. ANASTASI, KRISTINA
NUNGARAY, YU KUBOTA, & MANUELA GARZA, Sam Houston
State University—Three experiments were performed to investigate
production of ultrasonic vocalizations (USVs) in rat pups in response
to transport response elicitation with dorsal stimulation, using both
quantitative and qualitative measures. In Experiment 1, USVs were
recorded with tonic (holding) or phasic (gently waving) stimulation
with phasic producing increases in USV rate. In Experiment 2, USVs
were recorded with the pup passively held, suspended to induce the
dorsal immobility response, and suspended so as to induce a transport
response. Transport response elicitation increased number of USVs
above both dorsal immobility and passive handling. In Experiment 3,
USVs were recorded just prior to the mother’s retrieving the pup and
during retrieval. Actual retrieval increased both number and duration
of USVs, producing both quantitative and qualitative differences, over
preretrieval. The results are discussed with respect to the nature of the
pups’ responses, input of maternal stimulation, and possible mechanisms
for these differences.
(2050)
Refining the Visual Cortical Priming Hypothesis in Category
Learning by Humans and Rhesus Monkeys (Macaca mulatta).
MARIANA V. C. COUTINHO, JUSTIN J. COUCHMAN, JOSHUA S.
REDFORD, & J. DAVID SMITH, University at Buffalo (sponsored by
J. David Smith)—Humans show prototype-enhancement effects and
steep typicality gradients in dot-distortion categorization tasks. These
effects have been ascribed to visual cortical priming. To challenge and
refine this hypothesis, we compared performance by humans and
monkeys on two dot-distortion category tasks in which (1) the stimuli
were size invariant and (2) the stimuli varied greatly in size. Prototype
effects and typicality gradients were substantially the same in
the two tasks, for humans and monkeys. This constrains the visual cortical
priming hypothesis, because low-level visual-priming effects
would not show this robustness of performance to size change. There
may be higher level priming mechanisms involved in dot-distortion
categorization, or prototype-abstraction processes may not actually be
solely priming based.
76
(2051)
Comparing Implicit and Explicit Categorization Strategies in Humans
and Rhesus Macaques (Macaca mulatta). JUSTIN J.
COUCHMAN, MARIANA V. C. COUTINHO, & J. DAVID SMITH,
University at Buffalo—In an early dissociation between implicit and
explicit categorization, Kemler Nelson (1984) gave participants an
optional categorization task that could be performed by responding either
to overall family resemblance or to a single-dimensional criterial
rule. Explicit human learners often adopted the rule-based strategy;
incidental human learners often adopted the family-resemblance strategy.
In the present study, we replicated Kemler Nelson’s human experiment
and found the same dissociation. In addition, we extended
her paradigm to rhesus monkeys, asking whether they also have an explicit,
category-learning system that can be responsive to analytic
rules. Macaques heavily favored the family-resemblance strategy.
Even after many sessions and thousands of trials in the task, they
seemed to have little appreciation that a simple rule, based on one
stimulus dimension, could produce perfect categorization.
(2052)
Transfer Testing Provides Little Evidence of Commonality Between
Matching-to-Duration Tasks Involving Keylight and Food Presentations.
DOUGLAS S. GRANT, University of Alberta—Pigeons were
trained to discriminate between 2- and 8-sec durations of keylight and
food presentations. Different comparison stimuli were presented following
keylight and food durations (colors for one task and lines for
the other task). Following acquisition, the birds experienced two successive
transfer tasks in which the comparisons trained with one set
of durations were presented on trials involving the alternate set of durations.
In each transfer test, the duration-to-comparison mapping was
either consistent (i.e., both short samples associated with one comparison
and both long samples associated with the other comparison)
or inconsistent (i.e., one short and one long sample associated with
one comparison, and the other short and long sample associated with
the other comparison). Whether transfer involved a consistent or inconsistent
sample-to-comparison mapping had little effect on either
initial accuracy or rate of acquisition. Hence, duration tasks using keylight
and food durations are not functionally equivalent.
(2053)
Timing With Opportunity Costs: Concurrent Schedules Improve
Accuracy of Peak Timing. FEDERICO SANABRIA, Arizona State
University, ERIC A. THRAILKILL, Utah State University, & PETER R.
KILLEEN, Arizona State University—The temporal generalization
gradient produced by the peak procedure conflates detectability and
bias. We instituted concurrent ratio and interval schedules to manipulate
the opportunity cost of false alarms (early and late peak responses).
Concurrent tasks brought peak start and stop times closer to
the target time. The shifts were greatest for start times, which not only
moved closer to the target time, but whose coefficients of variation decreased.
The changes were inconsistent with several basic models of
timing.
• DECISION MAKING •
(2054)
Melioration Versus Maximization: Feedback- and Strategy-Driven
Models of Adaptive Behavior. HANSJOERG NETH, CHRIS R. SIMS,
& WAYNE D. GRAY, Rensselaer Polytechnic Institute (sponsored by
Wayne D. Gray)—Environments that confront cognitive agents with
a choice between local and global gains often evoke a behavioral pattern
known as melioration—a preference for immediate rewards over
higher long-term gains (Herrnstein, 1997; Tunney & Shanks, 2002).
We previously presented evidence that global feedback about expected
and optimal gains does not enable decision makers to reliably
overcome melioration in favor of maximization in a probabilistic
binary-choice paradigm (Neth, Sims, & Gray, 2006). Treating the
dilemma between melioration and maximization as a representational