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| Poster #285 Non-Monotonic Psychometric Functions for Phenyl Ethyl Alcohol. |
| E. Leslie Cameron1, Natalie Scalamera1, Brooke Bastian1, Shima T. Moein2, Richard L. Doty3 1Carthage College, Kenosha, WI, United States 2Sensonics International, Haddon Heights, NJ, United States 3University of Pennsylvania, Philadelphia, PA, United States |
Phenyl ethyl alcohol (PEA, a rose-like smelling odor) is one of the chemicals most widely used to determine olfactory thresholds. To our knowledge, no published data of its psychometric function have been reported. For some other chemicals (e.g., alpha-ionone, amyl acetate), olfactory psychometric functions are non-monotonic, exhibiting significant ‘notches’ at points along the function (Cameron et al., 2024; Marshall & Moulton, 1981; Cameron & Doty, AChemS, 2018; 2019). Trial-by-trial confidence tends to increase as concentration increases, generally mirroring performance (Cameron et al., 2024). In this study, we determined psychometric functions for PEA using a 2-alternative forced choice detection task that employed Sensonics’ Snap & Sniff® wands or Pop and Sniff® inhalers. On each trial, two stimuli were presented in rapid succession. One contained PEA at one of 10 predetermined concentrations and the other an odorless diluent. The participant’s task was to indicate which stimulus seemed stronger and to rate the degree of their confidence on a 9-point rating scale. In one condition, 14 undergraduates (3 M, 11 F) completed a single 30-minute test session of 60 trials. In another condition, 2 adults (1 M, 1 F) and 2 teenagers (1 M, 1 F) each completed 10 identical test sessions. As observed for other odorants that have been tested, consistent ‘notches’ at two concentrations were found using both types of stimulus presentation devices. Moreover, confidence increased exponentially with concentration and typically mirrored performance. Such discontinuities may provide insight into the underlying mechanisms involved in receptor-level processing and may explain some of the variability noted in point estimate threshold values. |