Psychometrics of odor quality discrimination: method for threshold determination.

Department of Psychology, Uppsala University, Box 1225, S-751 42 Uppsala, Sweden.
Chemical Senses (Impact Factor: 3.22). 11/2000; 25(5):493-9. DOI: 10.1093/chemse/25.5.493
Source: PubMed

ABSTRACT There is no natural physical continuum for odor quality along which an odor quality discrimination (OQD) threshold can be measured. In an attempt to overcome this problem, the substitution-reciprocity (SURE) method defines a framework for the measurement of an OQD threshold. More specifically, it (i) defines a threshold concept for OQD, including the quantification of qualitative change of the stimulus, and (ii) suggests how to avoid perceived intensity as an unwanted cue for discrimination. In doing this, the psychometric properties of odor quality in the case of eugenol and citral are investigated using both discrimination (experiment 1) and scaling (experiment 2). Based on discriminatory responses, a change of approximately one-third in stimulus content was needed to reach the OQD threshold for eugenol and citral.

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