Abstracts 2005 - The Psychonomic Society

Saturday Evening Posters 5009–5015
fordances change with changes in body shape (e.g., becoming more
accurate while a well-stuffed backpack is worn).
(5009)
Changes in Visual Awareness: Event-Related Brain Potential Correlates.
HARTMUT LEUTHOLD, University of Glasgow—In a recent
event-related brain potential (ERP) study (Koivistu & Revonsuo, 2003),
awareness of visual change has been associated with an early negative
ERP deflection over posterior electrodes. This study employed
rectangular stimuli that varied only in orientation. Thus, to investigate
whether the change-related ERP negativity is independent of the object
dimension changing, I conducted an experiment that used objects
defined by color and shape. In different change detection task blocks,
where memory set size (2 vs. 5 items) varied randomly, participants
were to indicate change in either color or shape. ERPs from 12 participants
were simultaneously recorded during task performance. A
negative amplitude shift over parieto-occipital electrodes, about
200 msec after stimulus onset, was triggered by detected changes, as
compared with undetected and no changes. In conclusion, the present
study strengthens the view that a posterior ERP negativity provides a
neural correlate of processes associated with changes in visual awareness.
(5010)
Repetition Blindness for Chinese Characters: Form and Meaning
Matter. CAILI WU, ALBRECHT W. INHOFF, & CYNTHIA M.
CONNINE, SUNY, Binghamton (sponsored by Albrecht W. Inhoff)—
Repetition blindness (RB) is the failure to detect the second occurrence
of repeated words presented in rapid serial visual presentation.
However, absolute repetition of two items is not the prerequisite for
RB. RB was found for two English words that were either visually or
phonologically similar. Yet there was little evidence for a semantic
contribution to RB. By using some unique properties of Chinese characters,
two experiments were conducted to investigate whether the
form, sound, and meaning of a Chinese character contributes to the
RB effect. The results showed form overlap alone was sufficient to
produce RB but that sound overlap alone was not adequate for RB to
occur. Given some form overlap (i.e., two characters shared the same
semantic radical), semantically related character pairs yielded more
RB than did semantically unrelated character pairs.
(5011)
Object Substitution Masking Interferes With Semantic Processing:
Evidence From ERPs. JASON E. REISS & JAMES E. HOFFMAN,
University of Delaware—Object substitution masking (OSM) refers to
impaired target identification caused by the common onset, but delayed
offset, of a surrounding dot mask. This effect is believed to result
from reentrant processes that replace the target representation
with the mask. However, little is known about the degree of processing
associated with masked targets. We investigated this issue by examining
the effect of OSM on the N400 ERP component, which reflects
the degree of semantic mismatch between a target and its
context. Participants read a “context” word followed by a semantically
related or unrelated “target” word surrounded by dots. As was expected,
delayed dot offset led to significantly reduced target identification accuracy.
Importantly, the N400 component was also diminished by
OSM. These results indicate that OSM interferes with target processing
prior to semantic analysis, demonstrating an important difference
between OSM and visual phenomena such as the “attentional blink,”
where semantic processing is independent of identification accuracy.
(5012)
Temporal Dynamics of Suppression in the Distractor Previewing
Effect. ALEJANDRO LLERAS, University of Illinois, Urbana-
Champaign, & JUN KAWAHARA, Hiroshima University—When a
visual search for a color oddball (e.g., a red diamond among green diamonds)
is performed, oddball-absent trials (for which no response is
required) affect performance on the subsequent oddball-present trial,
an effect known as the distractor previewing effect (DPE). Specifi-
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cally, the color of the distractors in the oddball-absent trial (e.g.,
green) suppresses responses to a target of that color in the subsequent
trial (a green target among red distractors), even though participants
report a target attribute uncorrelated with color. We investigated the
temporal dynamics of this suppression. On oddball-present trials, we
switched the color of the items at different points during the trial.
Oddball status and correct response were maintained before and after
the switch. Despite this, we found that color-switches occurring as
early as 100 msec into the trial reduced the magnitude of the DPE by
about 50%. Implications regarding the locus of the DPE are discussed.
(5013)
Speed–Accuracy Tradeoff in Reaction Times During Smooth Pursuit.
YASUHIRO SEYA & SHUJI MORI, Tokyo Metropolitan University—
We examined reaction times (RTs) during smooth pursuit eye movement
with different retinal eccentricities and stimulus velocities. In
Experiment 1, participants were asked to pursue a row of circular
frames moving at a constant velocity and to respond to the target presented
within one of the frames. In Experiment 2, the participants
were presented with stimuli identical to those used in Experiment 1
while fixating their eyes on stationary central points. The results of
Experiments 1 and 2 showed that the RTs during both smooth pursuit
and fixation increased with the retinal eccentricity. The RTs during
fixation increased with the stimulus velocity, whereas RTs during
smooth pursuit did not change systematically with velocity (although
there were large individual differences). We propose that the latter
finding is due to a tradeoff between response speed (RT) and pursuit
accuracy.
• ASSOCIATIVE LEARNING AND SKILL ACQUISITION •
(5014)
Imagine That! Motor Imagery Enhances Repetition Priming of
Sequences. ERICA L. WOHLDMANN, ALICE F. HEALY, & LYLE E.
BOURNE, University of Colorado, Boulder—We examined the efficacy
of motor imagery for sequence learning and skill acquisition.
Subjects participated in four experimental phases: familiarization,
training, testing, and recognition. Familiarization involved typing 32
four-digit numbers. During training, 64 different four-digit numbers
were presented five times each. The 80 subjects were assigned to four
training groups: The control group merely looked at each number; the
physical group typed each number; the imagery-move group imagined
typing each number while making finger movements; and the
imagery-grip group imagined typing each number while holding a
mouse to inhibit finger movements. At testing, which required typing
old and new numbers, all but the control group showed repetition
priming (i.e., an old–new difference). The recognition test indicated
that explicit memory was neither necessary nor sufficient for repetition
priming. These findings suggest that motor imagery can be used
to learn new sequence representations, but not necessarily new motor
skills.
(5015)
Observed Individual Differences by Controlling Any Timings of
Occurrences of Vast Study Events. TAKAFUMI TERASAWA, Okayama
University, TETSUYA YOSHIDA, Tokoha Gakuen University,
KYOKO MAEMOTO, Okayama Higashi Commercial High School,
ATSUSHI KATSUBE, Okayama University, & NOBUO OHTA, Tokyo
University of Social Welfare—We conducted a 5-week learning study
on the second-language (English) acquisition of high school students.
At a study phase, students were asked to rate their achievement (i.e.,
how for they had mastered the Japanese meaning of each English
word) for each English–Japanese pair word on a 4-point scale (0 = no
good at all, 1 = no good, 2 = good, and 3 = perfect). For all the pairs,
the number of study repetitions (1, 4) and occurrences of learning
events were controlled. For controlling the timing of occurrences of
vast study events (over 1 million), a new experimental design had to
be developed. The design also enables researchers to measure the ef-