4.45 – Human Olfactory Psychophysics

摘要: The field of psychophysics deals with describing the relationship between physical stimuli and their resultant perceptual phenomena within a rigorous, quantifiable framework. Here we report on state-of-the-art in human olfactory psychophysics. Olfactory perception can be described functionally hierarchical terms as consisting basic behavior detection, followed by more demanding task discrimination which calls upon short-term memory, culminating identification that consists not only detecting discriminating stimulus, but also pairing it verbal-semantic labels stored long-term memory. Here, use this functional hierarchy an organizational guide. Regarding detection thresholds, existing data is typified extreme variance, both across laboratories. This variance primarily result differences methods odorant delivery application statistical criteria. Despite there general agreement thresholds are very low, or other words, nose first-rate chemical detector. For example, if were to add just three drops ethyl mercaptan into one two Olympic swimming pools, average person would able detect pool had added odor. Regarding discrimination, humans discriminate small concentration molecular structure stimuli. increases perceived intensity. When using suprathreshold n-butyl alcohol standard, changes 7%. fraction similar those found vision audition. Similarly, smallest structure, such addition single carbon chain, results clearly discriminable stimuli. Regarding identification, odor mixtures suggests system identifies objects, whose formation depends previous associations. rules underlying link particular structural properties identity have been difficult establish, due part variability language describe odor. Understanding these remains biggest question psychophysics, arguably olfaction general, outline several being used effort solve mystery.