What information is used by the visual system to detect patterns? A standard model
hypothesizes that both spatial frequency and orientation information are processed by
independent channels, meaning there is no summation among channels. Despite consensus
among researchers on how the visual system sums spatial frequency and orientation
information there are data in the literature (Kersten, 1987) that ostensibly contradict the
standard model. To resolve this conflict, we measured the efficiency of spatial frequency
and orientation of filtered noise. To learn what information the visual system uses when
detecting filtered noise, we applied a technique that can determine the information used
to detect and discriminate filtered visual noise. In Chapter 2 the detection of spatial
frequency filtered noise is not only efficient but remains so with stimulus uncertainty and
extremely brief (10ms) stimulus duration. When the spatial frequency channel used was
measured, we found a fixed bandwidth channel as the spatial frequency of the pattern
was increased. To test the standard model, we implemented simulations of the standard
model and contrary to the interpretation, the standard model could predict detection of
spatial frequency filtered noise. Chapter 3 used spatial frequency filtered noise to relate
the detection and discrimination of filtered visual noise. A simple rule relates what information
observers use to detect and discriminate spatial frequency filtered noise. Chapter
4 extends the work of Chapter 2 to orientation information and found that orientation
filtered noise is detected efficiently. We again measured what information observers used
and found that, unlike SF filtered noise, observers use orientation in a flexible or adjustable
manner. / Thesis / Doctor of Philosophy (PhD)
| Identifer | oai:union.ndltd.org:mcmaster.ca/oai:macsphere.mcmaster.ca:11375/21062 |
| Date | January 2011 |
| Creators | Taylor, Christopher |
| Contributors | Bennett, Patrick, Sekuler, Allison, Psychology |
| Source Sets | McMaster University |
| Language | English |
| Detected Language | English |
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