title: Influences of feedback and ascending and descending trial presentations on perithreshold odor detection performance.
abstract: 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.
authors.affiliation: Smell and Taste Center and Department of Otorhinolaryngology: Head and Neck Surgery, University of Pennsylvania Medical Center, Philadelphia, PA 19104, USA. doty@mail.med.upenn.edu
authors.forename: Richard L
authors.initials: RL
authors.lastname: Doty
authors.forename: Jeffrey M
authors.initials: JM
authors.lastname: Diez
authors.forename: Sinan
authors.initials: S
authors.lastname: Turnacioglu
authors.forename: Donald A
authors.initials: DA
authors.lastname: McKeown
authors.forename: John
authors.initials: J
authors.lastname: Gledhill
authors.forename: Kelsy
authors.initials: K
authors.lastname: Armstrong
authors.forename: W William
authors.initials: WW
authors.lastname: Lee
mesh_terms: D000328:Adult; D030141:Feedback, Psychological / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D010626:Phenylethyl Alcohol / Q000737:chemistry* / Q000494:pharmacology; D012684:Sensory Thresholds / Q000502:physiology; D012903:Smell / Q000502:physiology*
chemical_list: D010626:Phenylethyl Alcohol