Rick Boven's Thesis
The use of multiple observers in signal detection theory: A method to remove
the effect of unique noise from experimental data
Richard Boven
1976
Submitted for the degree of Master of Arts in Psychology
Victoria University of Wellington, New Zealand
Abstract
This thesis reports an investigation of the use of multiple observer groups
in the theory of signal detectability. When an experimenter conducts a
psychophysical experiment his data contain the effect of noise which is unique
to each observer an can systematically affect his results. Since the
experimenter cannot adequately measure this noise he cannot assess its impact on
his data.
The mathematical theory of multiple observers suggests that is is possible to
remove the effect of this unique noise from signal detection data by using
multiple observer groups. Three experiments designed to demonstrate this result
are reported. The results suggest that the group-operating-characteristic (GOC)
curve of Watson can, if sufficient observers are run, be used to remove the
effect of unique noise from experimental data.
Applications of multiple observers to the measurement of the
ratio of unique noise variance to common noise variance are considered. It is
shown that the criteria adopted by the observers in the group affect both the
performance of the group and the estimate of the ratio of unique noise to common
noise.
Last updated
08 Nov 2009 04:37 PM
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