Sensory scales of taste intensity

Abstract

The subjective intensity of taste was scaled by the method of magnitude estimation in which Os assigned numbers to designate the apparent strength of stimulus concentrations. Substances used were sucrose, dextrose, maltose, fructose, saccharin, Sucaryl, sodium chloride, and During the past decade several separate studies have been made in this laboratory in order to continue the pioneering efforts of Beebe-Center who used a direct scaling procedure (fractionation) to determine the relation between stimulus concentration and the apparent strength of the resulting taste. An important outcome of the early work was the well-known gust scale (Beebe-Center & Waddell, 1948). Improvements in method have been made from time to time, and it has been found that a procedure based on some form of direct magnitude estimation has advantages over the one based on fractionation. Most of the following studies were student exercises designed to explore one or another aspect of the gustatory sense. The first magnitude estimations of taste intensity were carried out under the direction of Dr. Beebe-Center, After his death in 1958 some of the work was continued under my direction, and some under the direction of J. C. Stevens in an undergraduate laboratory course. Representative exponents derived from a few of the experiments have been noted elsewhere (e.g., Stevens, 1960). For related work by other investigators, see Ekman and Akesson (1965).A prime feature of the method of magnitude estimation lies in the freedom it gives the 0 to match numbers to stimuli. The O's task is to make the numbers proportional to the apparent intensity of the taste. This method of free number matching leads to ratio scales of taste sensation. The method contrasts with the well-known category rating scale, which is often used, but which restricts the O's responses to a finite set of numbers or adjectives. For an example of the use of a finite category scale, see the study of sweetness by Schutz and Pilgrim (1957).For reasons dealt with at length by Stevens and Galanter (1957), the category scale does not reveal the form of the psychophysical function that relates sensory intensity to stimulus intensity. Magnitude estimation, on the other hand, can, in principle, lead directly to a reasonably good estimate of the psychophysical function. Indeed, in every sense modality tested, the methods of direct, unconstrained matching have shown that the psychophysical relation is a power function. In several sense modalities the results of magnitude estimation have been confirmed by the cross-modality matching of one sensory intensity directly to another (Stevens, 1966). PROCEDURESince more than a dozen different students served as Es in the studies reported below, the details of the procedures were not well standardized. Nevertheless, the general features were similar. Solutions of the appropriate concentrations were prepared in advance with tap water (Cambridge, Mass.). The solutions were presented to the 0 at room temperature, one at a time, in small "shot" g...

The effects of viscosity upon perceived sweetness

“…The slopes are negative against Viscosity, suggesting that increasing the solvent viscosity diminishes sweetness. we igh t, level off -a departure from linearity that has consistently appeared in other studies (Moskowitz, 1968(Moskowitz, , 1970aStevens, 1969;Stone & Oliver, 1966). The exponent of the sweetness function for sucrose in log-log coordinates is higher than would be expected from previous studies, but the exponent is relatively constant (to within 20%) across the four log units of viscosity.…”

“…In addition, it incorporates a larger range of suprathreshold stimuli, and concerns the sweet ness-viscosity relation for two different types of sweeteners, sucrose and sodium saccharin, which have different growth functions for perceived sweetness (Stevens, 1969;Moskowitz, 1970b).…”

Bidirectional contrast, matching, and power functions obtained in sucrose consumption by rats

“…The results of many experiments conducted in this fashion, on a wide variety of sensory continua, suggest that sensory intensity (S) is related to physical intensity (I) by a power function, S = kl" (Stevens, 1969). The value of the exponent, n, has been found to vary with different sensory continua, with a value between 1.0 and 1.3 typical of sweetness judgments of sucrose, although lower values have sometimes been obtained (Meiselman, 1971;Moskowitz, 1971Moskowitz, , 1973Stevens, 1969). It is assumed that this function relates subjective sensory ratios of the judged stimuli to the physical ratios of these stimuli.…”

“…For example, in a typical experiment investigating the relative sweetness of sugar solutions, subjects might be instructed to assign numbers in proportion to the relative sweetness of each solution (Moskowitz, 1970). The results of many experiments conducted in this fashion, on a wide variety of sensory continua, suggest that sensory intensity (S) is related to physical intensity (I) by a power function, S = kl" (Stevens, 1969). The value of the exponent, n, has been found to vary with different sensory continua, with a value between 1.0 and 1.3 typical of sweetness judgments of sucrose, although lower values have sometimes been obtained (Meiselman, 1971;Moskowitz, 1971Moskowitz, , 1973Stevens, 1969).…”

The psychophysics of taste from the entropy of the stimulus

“…Therefore, a graph of magnitude estimate, F, against concentration, 1-1, is expected to deviate progressively more from linearity with increasing concentration, as shown in Figure 2. This deviation from linearity is seen very clearly in most of the experimental graphs for taste given by Stevens (1969). Equation 9 was derived by Norwich (1977Norwich ( , 1981a with reference to electrical activity in sensory neurons.…”