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Categorical Search: A (selective) Review of Behavioral and Computational Work| old_uid | 15387 |
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| title | Categorical Search: A (selective) Review of Behavioral and Computational Work |
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| start_date | 2015/03/26 |
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| schedule | 09h-10h30 |
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| online | no |
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| summary | Categorical search, the task of finding and recognizing categorically
-
defined targets
(e.g.,
cups, trash bins, etc.) has been a neglected research topic, with the majority of studies in the
search literature using instead picture previews of a target or other paradigms
providing
searchers with
precise knowledge of a target’s exact appearan
ce. Behavioral and
computational work from my laboratory on the topic of
how
eye movements
are directed
during categorical search will be reviewed. Behaviorally, we show that eye movements can
be guided to categorically
-
defined targets
,
a possibility tha
t had been debated. We also show
that this categorical guidance is proportional to the availability of target
-
defining information,
is
sensitive to subtle categorical similarity relationships, and is modulated by factors known to
affect categorization,
su
ch as the hierarchical level used to specify
a
categorical target
.
Computationally, we borrow features and techniques from computer vision to model the eye
movements made during categorical search. We show that this model can predict several core
aspects
of search behavior, including set size effects and the percentages of initial eye
movements to a target (a conservative measure of search guidance). Recent work will also be
discussed that uses SVM
-
based classifiers to decode
the category of target that
a person is
searching for from
the
nontarget
objects
that they preferentially fixate
on target
-
absent
trials
—
reading a searcher’s mind by analyzing their fixations
.
We conclude that categorical
search is very similar to target
-
specific search, with the di
fference being that the visual
features discriminating a target category from nontargets must be learned and retrieved from
long
-
term memory before being used to guide movements of attention and gaze. |
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| responsibles | Rigalleau, Croizet |
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