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Unformatted text preview: 1068 The American Journal of Clinical Nutrition 31 : JUNE 1978, pp. 1068-1077. Printed in U.S.A. The psychophysics of taste Linda M. Bartoshuk, Ph.D. ABSTRACT Modern psychophysical studies of sensory systems have produced new insight into sensory function and new techniques that have application to the clinical evaluation of taste. Most previous taste evaluation has been done with threshold measures that are subject to a variety of problems and that also fail to provide an accurate picture of suprathreshold sensitivity. The scaling of suprathreshold intensity reflects a patients taste world more accurately than thresholds. Am. I. Clin. Nutr. 31: 1068-1077, 1978. Taste dysfunction is a disturbing problem for many individuals. Taste anomalies can affect health not only through effects on food and fluid intake but also because of the general loss of morale accompanying the loss of an important source of pleasure. Accurate clinical assessment of taste func- tion is essential both to understand the source of dysfunction and to suggest possi- ble remedial measures. Modern psycho- physical studies of sensory processes have provided techniques that were designed for the laboratory but may have application to the clinic as well. One important insight produced b the psychophysical study of the senses is that threshold measurements are of limited usefulness because they do not describe the dynamic range of sensory func- tion . The measurement of thresholds can also offer problems to the unwary. The following discussion deals first with the ma- jor pitfalls to be encountered in threshold measurement and second with scaling pro- cedures that offer advantages when used in conjunction with or instead of threshold procedures. Threshold procedures Detection and recognition thresholds The detection threshold is the lowest con- centration at which a taste can just be detected while the recognition threshold is the lowest concentration at which the qual- ity of a taste stimulus can be recognized. The threshold is a statistical concept. By convention, a threshold value usually refers to the concentration that is detected or recognized 50% of the time. The up-down procedure A variety of techniques can be used to generate taste thresholds (see References 1 and 2 for a general discussion of threshold methodology). In practice , highly efficient methods are the most desirable in order to decrease the time required to get a stable value . One of the most efficient procedures is the up-down or staircase technique (3). With this technique , the subjects responses determine the concentrations tested: if the subject indicates the presence of a stimulus, then the concentration of the test stimulus is decreased on the next trial while if the subject fails to indicate a stimulus, then the concentration is increased . This generates a series of runs of the subjects perception of the presence or absence of the stimulus....
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This note was uploaded on 06/13/2011 for the course PSYCH 115 taught by Professor Shaine during the Spring '07 term at UCLA.
- Spring '07