Attending to visual information for perception and recognition

Bonnar, Elizabeth-Ann (2005) Attending to visual information for perception and recognition. PhD thesis, University of Glasgow.

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A fundamental function of the visual system, and other sensory systems, due
to resource limitations, is to optimally select task-relevant information from the
barrage of information impinging the retina. In a series of experiments different
aspects of attention to visual information for perception and recognition are
Firstly, what information is selected? In Chapter 2, I begin with addressing
the generic problem of knowing which information drives the perception of a
stimulus. As a case study example, a first experiment using Bubbles (Gosselin
and Schyns, 2001) determines the specific information underlying the perception
of the stable percepts of an ambiguous image and shows that this information is
grounded in different spatial filters processing each image interpretation. A
further experiment employs frequency-specific adaptation to induce a perception
of the image that is orthogonal to the adapting frequencies, validating this
information drives the selective perception of the ambiguous image.
Secondly, if we know the subset of information that is selected for the
perception of an input, can the processing of information underlying a percept be
selectively suppressed, thereby inducing an alternative percept? In the
experiments of Chapter 3, I further apply this spatial frequency adaptation
method to test the relevance of local image features for the perception of the
ambiguous image, and the recognition of gender in hybrid faces. While the
results of the experiment on the perception of the ambiguous image suggest an
effective method for testing the role of local stimulus information for perception,
the results of the experiment on the recognition of gender in faces showed no
effect of adaptation region on perception of gender.
Thirdly, how does selective information use evolve with learning? And what
are the mechanism(s) that enable this learning? In Chapter 4, I investigated the
evolution of information use in the discrimination of unfamiliar faces using a
perceptual learning paradigm. I used the method of noise masking to examine
the facial regions observers used, over time, for successful discrimination, and to
determine the mechanisms underlying performance improvements. The results
showed that the efficiency of observers to use the information available increased
with learning differentially across different regions of the face.
Supplementary to examining attention to information in terms of the
information content of the stimulus, another series of experiments investigated
the effect of attention on the temporal dynamics of processing visual information,
and the locus of this effect within the stream of information processing. Using
spatial pre-cueing to manipulate attention and a speed-accuracy trade-off (SAT)
method to examine the full time-course of visual processing, I analysed, in
addition to the behavioural response and the parameters of the SATfunction, the
lateralised readiness potential (LRP)and other components of the event-related
brain potentials (ERPs) to determine the locus of any attentional modulations on
the speed of processing. The results of three experiments showed that attention
can speed up visual information processing, and that the locus of this effect is at
later processing stages related to the categorisation of a stimulus.

Item Type: Thesis (PhD)
Qualification Level: Doctoral
Subjects: B Philosophy. Psychology. Religion > BF Psychology
Colleges/Schools: College of Science and Engineering > School of Psychology
Supervisor's Name: Leuthold, Mr Hartmut
Date of Award: 2005
Depositing User: Ms Dawn Pike
Unique ID: glathesis:2005-4907
Copyright: Copyright of this thesis is held by the author.
Date Deposited: 30 Jan 2014 15:08
Last Modified: 30 Jan 2014 15:08

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