Influences of Feedback and Ascending and Descending Trial Presentationson Perithreshold Odor Detection Performance

The influences of feedback and ascending and descending trial sequences on the ability of 135 college-aged subjects to detect phenyl ethyl alcohol odorant concentrations ranging from 10–9 to 10–5.5 v/v were examined in a two-alternative forced-choice test paradigm. At the highest concentrations, asc...

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Bibliographic Details
Published in:Chemical senses 2003-07, Vol.28 (6), p.523-526
Main Authors: Doty, Richard L., Diez, Jeffrey M., Turnacioglu, Sinan, McKeown, Donald A., Gledhill, John, Armstrong, Kelsy, Lee, W. William
Format: Article
Language:English
Subjects:
feedback
method of limits
phenyl ethyl alcohol
psychophysics
threshold
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Summary:The influences of feedback and ascending and descending trial sequences on the ability of 135 college-aged subjects to detect phenyl ethyl alcohol odorant concentrations ranging from 10–9 to 10–5.5 v/v were examined in a two-alternative forced-choice test paradigm. At the highest concentrations, ascending trial sequences produced better performance than descending trial sequences; the reverse was true at the lowest concentrations. There was a tendency for feedback to improve performance marginally at the lowest two odorant concentrations presented. In the region associated with a traditional detection threshold calculation (i.e. at the 75% performance point in a two-choice detection task), no influences of feedback or direction of trial sequence were apparent. These data indicate that the effects of explicit feedback and trial sequence direction depend upon the segment of the peri-threshold stimulus concentration continuum evaluated.
ISSN:0379-864X
1464-3553
DOI:10.1093/chemse/28.6.523