S1 (FriAM 1-65) - The Psychonomic Society

Friday Afternoon Papers 99–104
Observers overestimate the slopes of hills with verbal measures, but
are more accurate with body-based motor matching techniques, an example
of contrast between cognitive and sensorimotor visual information.
We replicated this effect using arm posture measured with
digital photography rather than a tilt board for the motor measure,
eliminating body contact with the hardware. Judged slopes are too
steep at long distances, measured by having observers estimate segments
of slopes between themselves and markers; at 16 m an 11º hill
is verbally estimated at nearly 30º; the motor estimate is much lower.
At 1 m, however, estimates are more accurate with both measures.
What happens when observers traverse the slope before estimating it,
giving them short-distance, presumably more accurate perceptual information
at every point on the slope? Their overestimates are just as
great as those of observers who did not traverse the slope. Appearance
dominates knowledge of the terrain.
3:10–3:25 (99)
The Perception of Four-Dot Configurations. MARY C. PORTILLO,
CARL HAMMARSTEN, SHAIYAN KESHVARI, STEPHEN W.
JEWELL, & JAMES R. POMERANTZ, Rice University (read by
James R. Pomerantz)—Perceivers see stars in the night sky configured
into dozens of nameable constellations. With simpler stimuli, twopoint
configurations are organized into a straight line, and three points
into a triangle. How do we perceive configurations of four points, as
when four coins are tossed randomly on the floor: as quadrilaterals,
as straight lines, curves, Y patterns, Ls, Ts, or yet others? We presented
328 patterns that systematically sampled the space of all possible
4-dot arrangements (ignoring size scale, orientation, and reflections)
for subjects to free-classify based on perceived similarity. We
then cluster-analyzed their responses. The structure of their classifications
was captured by a hierarchy of 14 clusters of patterns. The
first bifurcation occurred between patterns having 3 dots in a straight
line versus those that did not. Further branches suggest an ordered set
of rules for grouping dot patterns, including grouping by proximity,
linearity, parallelism, and symmetry.
3:30–3:45 (100)
Spationumerical Associations Between Perception and Semantics.
PETER KRAMER, IVILIN STOIANOV, CARLO UMILTÀ, &
MARCO ZORZI, University of Padua (sponsored by Johannes C.
Ziegler)—Stoianov, Kramer, Umiltà, and Zorzi (Cognition, in press)
found an interaction, between visuospatial and numerical information,
that is independent of response selection effects (e.g., the SNARC effect).
This Spatial-Numerical Association between Perception and Semantics
(SNAPS) emerges when a spatial prime follows (backward
priming), but not when it precedes (forward priming), a numerical target.
Here, we investigate the time course and nature of the SNAPS effect.
We used nonspatial, verbal parity judgments and number comparisons
and, to dissociate the SNAPS effect from other numerical
effects, we compared conditions with and without priming. The results
show that the SNAPS effect is inhibitory and peaks when the
prime follows the target by about 100 msec. Moreover, we observed
a main effect of number size even in the parity judgment task, contrary
to earlier claims. This latter finding has important implications
for current models of the representation of numerical magnitude.
Selective Attention
Regency ABC, Friday Afternoon, 4:10–5:30
Chaired by Zhe Chen, University of Canterbury
4:10–4:25 (101)
Implicit Perception in Object Substitution Masking. ZHE CHEN,
University of Canterbury, & ANNE TREISMAN, Princeton University—Object
substitution masking (OSM; Enns & Di Lollo, 1997)
refers to reduced target discrimination when the target is surrounded
by a sparse mask that does not overlap with the target in space but
16
trails it in time. In two experiments, we used a novel approach to investigate
the extent of processing of a masked target in OSM. We measured
response compatibility effects between target and mask, both
when the offsets were simultaneous and when the mask offset was delayed.
Participants made a speeded response to the mask followed by
an accuracy only response to the target, then categorizing their responses
to the target as “see” or “guess.” Targets and masks matched
or differed at a feature level in Experiment 1 and at a categorical level
in Experiment 2. Evidence for OSM as well as a dissociation between
perception and awareness was found in both experiments.
4:30–4:45 (102)
Intertrial Biasing of Selective Attention Leads to Blink-Like Misses
in RSVP Streams. ALEJANDRO LLERAS & BRIAN LEVINTHAL,
University of Illinois, Urbana-Champaign—When participants are required
to report the case of the color-oddball letter in a single-target
RSVP stream, their ability to do so is modulated by the position of the
target in the RSVP stream, and more crucially, by the match or mismatch
between the current target color and the color of distractors in
the prior RSVP stream. When the target is presented in the color of
the distractors in the previous trial RSVP stream, participants very
often miss the target (performance is at chance) when the target is presented
early on in the RSVP stream. Performance recovers for later
target positions in the RSVP stream. The pattern of performance (cost
and recovery) is strongly reminiscent of the attentional blink, even
though only one target is to be detected on any given trial and more
than 2 sec have elapsed since the end of the previous trial.
4:50–5:05 (103)
The Time Course of Goal-Driven Saccadic Selection. WIESKE
VAN ZOEST & MIEKE DONK, Vrije Universiteit, Amsterdam (sponsored
by Mieke Donk)—Four experiments were performed to investigate
goal-driven modulation in saccadic target selection as a function
of time. Observers were presented with displays containing
multiple homogeneously oriented background lines and two singletons.
Observers were instructed to make a speeded eye-movement to
one singleton in one condition and the other singleton in another condition.
Simultaneously presented singletons were defined in different
dimensions (orientation and color in Experiment 1), or in the same dimension
(i.e., orientation in Experiment 2, color in Experiments 3 and
4). The results showed that goal-driven selectivity increased as a function
of saccade latency and depended on the specific singleton combination.
Yet, selectivity was not a function of whether both singletons
were defined within or across dimensions. Instead, the rate of
goal-driven selectivity was related to the similarity between the singletons;
when singletons were dissimilar, accuracy as a function of
time increased more rapidly than when they were similar.
5:10–5:25 (104)
Tracking of Visual Objects Containing Textual Information.
LAURI OKSAMA & JUKKA HYÖNÄ, University of Turku (sponsored
by Jukka Hyönä)—Do properties of textual identity information
associated with moving targets influence visual tracking? In realworld
visual environments, such as air traffic displays, targets to be
tracked contain textual information (e.g., call signs). In the present
study, the textual information appeared within rectangles that moved
around the computer screen. Four factors were manipulated in the experiments:
(1) number of targets (2–6), (2) length of textual information
(5 vs. 10 character words), (3) familiarity of textual information
(existing words vs. pronounceable pseudowords), and (4) speed of object
movement. We observed that performance accuracy decreased as
a function of target set-size, text length, word unfamiliarity, and target
speed. We argue that the results are consistent with the recently
proposed serial model of dynamic identity–location binding (MOMIT),
which states that identity–location bindings for multiple moving objects
become more difficult when target identification consumes more
time (e.g., as text length increases).