Abstracts 2005 - The Psychonomic Society

Posters 3015–3022 Friday Evening
familiar toys and transparent boxes, either empty or containing familiar
objects, and (2) that included separate balls, pairs of balls with
rigid or flexible connectors (dumbbells), and balls in bags. Children
never counted filled containers, neither transparent boxes nor bags.
Adults consistently counted both filled and empty transparent boxes;
some also counted filled bags. Children did count empty containers
if they were the only objects presented on a trial and on trials following
all empty-container trials. Children never counted the dumbbell
connectors in the dumbbells (i.e., they never counted a dumbbell as
three things); adults did. Apparently, a relationship of containment or
connection with a salient object masks the individuation of the less
salient object for preschoolers, but not for adults.
(3015)
Breaking Weber’s Law: Systematic Deviations in Temporal Production
and Discrimination in Pigeons and Rats. FEDERICO SANA-
BRIA, Arizona State University, LEWIS A. BIZO, Southern Cross University,
& PETER R. KILLEEN, Arizona State University—Weber’s
law is frequently purported to be a ubiquitous feature of time perception.
In two experiments, we tested the timing performance of rats and
pigeons, using two timing tasks (temporal discrimination and production)
across a wide range of intervals (from milliseconds to tens
of seconds). The performance of both species systematically deviated
from Weber’s law in both timing tasks: Coefficients of performance
variation were relatively high for very short durations and then decreased
to a minimum for a range of intermediate intervals, as is predicted
by generalized Weber’s law; however, they then increased for
longer durations. A model based on a radix counter that allows for lost
pacemaker counts from an internal clock (Killeen & Taylor, 2000;
Killeen & Weiss, 1987) accommodated the U-shaped pattern.
(3016)
Psychological Time Distortions in Judging Minute-Long Intervals
Retrospectively. SIMON GRONDIN & MARILYN PLOURDE, Université
Laval—Fifty participants were asked to perform five different
cognitive tasks lasting 2, 3.5, 5, 6.5, and 8 min, respectively. After
completing the series of tasks, they were asked to estimate retrospectively
the duration of each one. Psychophysical analyses linking psychological
time to physical time revealed that the value of the slope,
when expressed with the power law, was about .48. The coefficient of
variation, or the ratio of variability to estimated time, ranged from .38
(at 2 min) to .28 (at 8 min). A task effect was observed only at Position
1 for estimated time, whereas no position effect was observed for
each task. There was no significant position or task effect for the coefficient
of variation. At the individual level, the results revealed severe
psychological time distortions. For instance, 2 and 8 min were
sometimes estimated as the same duration.
(3017)
Varying Duration and Location of a Tone in Time Production. JULIE
CHAMPAGNE & CLAUDETTE FORTIN, Université Laval—Manipulating
location of signals in time productions lengthens produced intervals
in proportion to the duration for which the signal is expected.
This effect was attributed to attention sharing between the timing and
the monitoring of the source of the signal. The present study examines
whether the location effect is influenced by the processing requirements
of the signal. A tone was used in a high- or low-frequency
discrimination task, the tone being either short (10 msec) or long
(150 msec). Participants were tested in two sessions with conditions
of tone duration counterbalanced. The location effect was stronger
when participants were tested first in the short-tone condition than
when they were tested first in the long-tone condition. This was explained
by a sampling strategy developed in the first experimental session
that participants maintain during the whole experiment.
(3018)
Remembering the Rate and Duration of Naturalistic Events. MARI-
LYN G. BOLTZ, Haverford College—In everyday behavior, there are
90
many situations that require one to judge an event’s rate and/or total
duration. The purpose of the present research is to compare the recognition
memory for these two temporal dimensions. Experiment 1 revealed
that people are able to incidentally learn the inherent rate of
various ecological sounds that vary in their structural characteristics.
Experiment 2 further demonstrated that rate information is both better
remembered and acquired after a fewer number of learning trials
than is event duration. Lastly, Experiment 3 systematically manipulated
participants’ attending to rate, duration, and pitch information
in order to assess whether these three structural dimensions are jointly
or independently encoded into memory. This relationship, in turn, has
both practical and theoretical implications.
(3019)
Assessment of Numerosity by Tamarins. JULIE J. NEIWORTH,
ALISON LEWIS, & MAREN SONSTEGARD, Carleton College—
Tamarins were trained in two different tasks, one involving a discrimination
of a particular number presented simultaneously on a
three-dimensional visual array and one involving a discrimination of
a particular number of sequentially presented items. Tests of generalization
verified relative numerosity assessment in both tasks initially.
With more training of two particular numbers in each task, generalization
tests showed tamarins subitizing, rather than assessing, relative
numerosity. As Wright, Colombo, and others have found with categorization
tasks, training with multiple items shifted tamarins’
assessment to a more complex method.
(3020)
Scalar Effects in Birds’ Visual Discrimination of Numerosity. JACKY
EMMERTON & JENNIFER RENNER, Purdue University—Several
models of numerical discrimination posit scalar effects—that is, an increase
in the variance of behavioral choices proportional to stimulus
magnitude (numerical value). Pigeons were trained to discriminate
pairs of anchor numerosities (ranging from 2 vs. 7 to 20 vs. 80). They
demonstrated both interpolation and extrapolation of their choices in
tests with novel values. Psychophysical functions were similar within
a given ratio of anchor values when absolute numerosities differed.
Points of subjective equality (PSEs) conformed to geometric means
of the anchor numerosities, and difference limens increased in proportion
to PSEs. Birds’ performance was robust under various control
conditions, including randomizing the array configurations and
array element sizes and equating across arrays for summed brightness
and area. Effects found across a range of numerosities with these visual
arrays were similar to those previously reported across species
when discrimination of number (as well as time) was based on sequential,
nonvisual items.
(3021)
Absolute Timing. JONATHON D. CRYSTAL, University of Georgia—
Independent groups of rats were trained with a 100-sec (n = 14), 24-sec
(n = 7), or 12-sec (n = 7) fixed interval (FI) procedure. The postreinforcement
pause (PRP; latency to the first response after food) was
measured. Temporal uncertainty differed between the three conditions
when measured on a relative time scale (i.e., PRP/FI); temporal uncertainty
was approximately the same when measured on an absolute
time scale (i.e., FI � PRP). Timing was optimal (PRP = FI) for the
100- and 12-sec groups. The data provide support for the absolute timing
hypothesis (i.e., temporal uncertainty is constant in absolute time,
rather than in relative time).
(3022)
Testing a Basic Assumption of Interval Models of Short-Interval
Timing: Does the Internal Clock Work Like a Stopwatch? J. DEVIN
MCAULEY, LORI CURTINDALE, & KEVIN C. H. PANG, Bowling
Green State University—Interval models of short-interval timing posit
three independent processing components: an internal clock used to
estimate duration, a reference memory used to store information about
duration, and a comparison mechanism used to judge relative dura-