S1 (FriAM 1-65) - The Psychonomic Society

Friday Evening Posters 3051–3056
MCCARLEY, University of Illinois, Urbana-Champaign, & CLAIRE E.
LITTLEFIELD, YUSUKE YAMANI, CHRISTINE M. KEMP, &
JEFFREY L. THOMSON, SUNY, Geneseo—Certain pairs of stimuli
yield asymmetric RT patterns in visual search. Specifically, targets
defined by the presence of a unique feature (e.g., a Q among Os) are
found more efficiently than targets defined by the absence of a feature
(e.g., an O among Qs). Horstmann et al. (2006) showed similar
asymmetries in flanker tasks, with targets defined by the presence of
a feature yielding weaker flanker compatibility effects than targets defined
by the absence of a feature. To examine the basis of this asymmetry,
we manipulated the separation between color-cued target and
flanker items embedded among gray filler items. Data showed that
asymmetrical compatibility effects were most pronounced at small
target–flanker separations, and further analyses suggested that the
asymmetry was the result of spatially mediated competitive interactions
between the target and flanker. Specifically, flankers possessing
the defining feature compete more strongly for spatially localized attentional
resources, thus producing stronger interference.
(3051)
Attentional Mechanisms in Simple Visual Detection. CHARLES C.
LIU & PHILIP L. SMITH, University of Melbourne (sponsored by
Philip L. Smith)—Recent spatial cuing studies suggest that detection
sensitivity can be enhanced by the allocation of attention. These results
are ambiguous, however, because cuing effects could be due to
uncertainty reduction rather than signal enhancement. In displays with
no uncertainty, cuing effects are observed only if the target is backwardly
masked—a phenomenon known as the mask-dependent cuing
effect. We investigated this effect in four experiments using the response
signal paradigm. When targets were unmasked, cues failed to
improve detection accuracy when uncertainty was eliminated (Experiment
1), but large cuing effects were obtained when uncertainty was
present (Experiment 2). When targets were masked, stronger cuing effects
were obtained with a backward pattern mask (Experiment 3) than
with a simultaneous noise mask (Experiment 4). Despite some individual
differences, the mask-dependent cuing effects were not due
solely to an external noise exclusion mechanism.
(3052)
How Reward Changes Visual Search. CLAYTON HICKEY & JAN
THEEUWES, Vrije Universiteit Amsterdam (sponsored by Jan
Theeuwes)—Human behavior is guided by environmental feedback;
when we find that our performance results in a positive outcome, we
are likely to continue to act in a similar manner. In this poster, we present
results suggesting that this conditioning plays an important role
in guiding attention in visual search. Participants completed a task
based on the additional singleton paradigm. Each correctly performed
trial was followed by either a large or a small reward. When a trial was
followed by a high reward, the attentional set established for that trial
appeared to be reinforced, as evidenced by fast responses in the next
trial when the same attentional set was required. No such reinforcement
was found following low-reward trials, with some subjects
showing a propensity to abandon the set that resulted in less reward.
These results suggest that reinforcement plays a critical role in the establishment
and maintenance of attentional set.
(3053)
Control of Spatial Shifts of Attention in the Auditory Modality.
JESSICA J. GREEN & JOHN J. MCDONALD, Simon Fraser University
(sponsored by John J. McDonald)—Recently, we reconstructed the
timing and anatomical sources of brain activity associated with attentional
control in vision. Occipital, parietal, and frontal cortices
were activated in succession within 500 msec of a signal to shift attention.
Parietal and occipital areas were then reactivated in succession
prior to the appearance of a visual target. Here, we investigated
whether an analogous sequence of activations would occur during
shifts of attention in the auditory modality. An auditory cue was used
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to direct attention to the likely location of an impending auditory target.
We examined beamformer sources of low-frequency electroencephalographic
activity during the cue–target interval. Attentional
control was associated with the same sequence of parietal and frontal
activations found in vision, except that anticipatory biasing was seen
in auditory, rather than visual, cortex. These results suggest that a single
cortical system mediates voluntary control of spatial attention in
the auditory and visual modalities.
(3054)
Attention Capture in the Face of Changing Attentional Control Settings.
MEI-CHING LIEN, Oregon State University, ERIC RUTHRUFF,
University of New Mexico, & JAMES C. JOHNSTON, NASA Ames
Research Center—Studies have shown that the involuntary capture of
spatial attention by objects is contingent on whether their properties
match what a person is looking for (top-down control). Even salient
objects often fail to capture attention when they do not match topdown
attentional control settings. In most previous studies, however,
control settings were fixed. What happens in the real-world case
where settings change moment by moment? Does the current setting
determine what captures attention, or is there historesis for the previously
used setting? Do changes in control settings make the attentional
system more vulnerable to capture by salient objects? New experiments,
using color as the top-down control property, showed that
attentional capture is contingent primarily on the current attentional
settings. Attention was captured neither by abrupt onsets nor by boxes
in the nontarget color relevant on the very last trial. People have a remarkable
ability to flexibly adjust attentional control settings.
(3055)
Attentional Preference in Selective Reaching: Location Versus Response
Efficiency. TIM WELSH, University of Calgary, & MICHELE
ZBINDEN, ETH—Tipper, Lortie, and Baylis (1992) found that distractors
between the home position and the target caused more interference
in a selective reaching movement than distractors farther from
the home position. Based largely on this “proximity-to-hand” effect,
Tipper et al. proposed that attention can be distributed in an actioncentered
framework such that the interference caused by a specific
stimulus is dependent on the to-be-performed action. The purpose of
the present experiment was to determine whether there is an attentional
preference for stimuli close to the starting position of the reach
(“proximity-to-hand” effect) or for stimuli that afford more efficiently
executed actions regardless of location. The results support an attentional
preference for the most efficient response, since the largest interference
effect was observed when the distractor afforded an action
with a lower index of difficulty than the target, even though that distractor
was farther from the home position than was the target.
• AUTOMATIC PROCESSING •
(3056)
Within- and Between-Hands Simon Effects for Object Locations and
Graspable Components. DONGBIN CHO & ROBERT W. PROCTOR,
Purdue University (sponsored by Robert W. Proctor)—Three experiments
examined the Simon effect for stimulus locations and graspable object
components as a function of whether responses were made with fingers
on the same or different hands. When the relevant dimension was
stimulus color, the Simon effects for irrelevant dimensions of stimulus
location and side of a frying pan handle were of similar size for
the within- and between-hands response conditions. However, the
between-hands Simon effect was larger than the within-hands effect
when upright-inverted orientation judgments were made for the frying
pan. This difference was not evident when the handle was disembodied,
or separated, from the body of the frying pan. These results
suggest that both relative position of the object part and a grasping affordance
contribute to performance when responses to an object property
are made by different hands.