Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Taste Threshold”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 937 records · Page 52Linked to original sources
PubMed2001

Covariation in individuals' sensitivities to bitter compounds: evidence supporting multiple receptor/transduction mechanisms.

People vary widely in their sensitivities to bitter compounds, but the intercorrelation of these sensitivities is unknown. Our goal was to investigate correlations as a function of individual sensitivities to several bitter compounds representative of different chemical classes and, from these correlations, infer the number and variety of potential bitterness transduction systems for these compounds. Twenty-six subjects rated and ranked quinine HCl, caffeine, (-)-epicatechin, tetralone, L-phenylalanine, L-tryptophan, magnesium sulfate, urea, sucrose octaacetate (SOA), denatonium benzoate, and n-propylthiouracil (PROP) for bitterness. By examining individual differences, ratings and rankings could be grouped into two general clusters--urea/phenylalanine/tryptophan/epicatechin, and quinine/caffeine/SOA/denatonium benzoate/tetralone/magnesium sulfate-none of which contained PROP. When subjects were grouped into the extremes of sensitivity to PROP, a significant difference was found in the bitterness ratings, but not in the rankings. Therefore, there are also subjects who possess diminished absolute sensitivity to bitter stimuli but do not differ from other subjects in their relative sensitivities to these compounds.

Adolescent↗
PubMed2003

Changes in stimulus salience as a result of stimulus preexposure: evidence from aversive and appetitive testing procedures.

In two experiments, rats received preexposure to three compound flavor stimuli, AX, BX, and CX, where X represents a saline solution. AX and BX were presented in alternation; CX, on a separate block of trials. The value of X was then modified, being devalued by aversive conditioning in Experiment 1, and rendered valuable by the induction of a state of salt need in Experiment 2. When given a choice between BX and CX, the rats consumed more of BX than of CX in Experiment 1, and more of CX than of BX in Experiment 2, suggesting that B and C differed in their ability to modulate the response governed by the X element. It was suggested that blocked preexposure to CX reduces the salience of the C stimulus but that the salience of B is maintained by preexposure in which BX is alternated with AX. The implications of this result for the phenomenon of perceptual learning are discussed.

Animals↗
PubMed1990

Perceptual integration of tertiary taste mixtures.

Integration psychophysics was used to explore the taste perception of mixtures of sucrose, fructose, and citric acid. Three levels of each stimulus were varied in a 3 x 3 x 3 factorial design. Subjects rated total intensity, sweetness, and acidity of the 27 mixtures on graphic rating scales. Consistent with earlier work, the perceived total intensity of the tertiary mixtures was found to be dictated by the intensity of the (subjectively) stronger component alone (i.e., either the integrated sweetness or the acidity, whichever was the more intense). In contrast, the sweetness and acidity of the mixture were susceptible to mutual suppression: Sweetness suppressed acidity, acidity suppressed sweetness. There was, however, a difference between sucrose and fructose in their interactions with citric acid, fructose being the more susceptible to suppression. This selectivity of suppression indicates that the two sweetnesses could not have been inextricably integrated. Implications for taste coding are discussed, and the findings are reconciled in terms of two separate coding mechanisms: one for taste intensity, another for taste quality.

Adult↗
PubMed1992

Effects of context on sweet and bitter tastes: unrelated to sensitivity to PROP (6-n-propylthiouracil).

In a double-shifting context paradigm, subjects gave magnitude estimates of the perceived intensity of qualitatively dissimilar taste substances (saccharin and quinine, sucrose and quinine) or qualitatively similar ones (saccharin and sucrose), with each pair of substances taking on different contextual sets of concentrations in different sessions. The dissimilar pairs produced substantial differential effects of context (e.g., a particular concentration of saccharin or sucrose was judged more intense than a particular quinine in one contextual setting, less intense in another), but the similar pair did not. This result accords with the hypothesis that differential context effects depend on qualitative similarity. Contrary to expectations, however, the magnitude of the context effect did not differ in tasters and nontasters of the bitter substance 6-n-propylthiouracil (PROP), groups previously shown to differ in sensitivity to bitterness in saccharin. Similarity judgments suggest that saccharin and sucrose were qualitatively alike for all subjects, regardless of sensitivity to PROP.

Attention↗
PubMed1996

Monogeusia for fructose, glucose, sucrose, and maltose.

We investigated the ability of subjects to discriminate sugars with a whole-mouth forced-choice paradigm, in which a standard solution was compared with a test solution of varied concentration. Discrimination probabilities were U-shaped functions of test concentration: for 6 subjects and pairwise combinations of fructose, glucose, and sucrose, discriminability always declined to chance over a narrow range of test concentrations. At concentrations < or = 100 mM, maltose was indiscriminable from fructose but discriminable at higher concentrations for 4 subjects. By analogy with the monochromacy of night vision, whereby any two lights are indiscriminable when their relative intensities are suitably adjusted, we call the gustatory indiscriminability of these sugars monogeusia. The simplest account of monogeusia is that all information about the indiscriminable sugars is represented by a single neural signal that varies only in magnitude. The discriminability of maltose from the other sugars at higher concentrations is consistent with the hypothesis that maltose also activates a second gustatory code.

Adult↗
PubMed1992

Contextual and sequential effects on judgments of sweetness intensity.

Presenting stimuli from skewed concentration distributions affects mean responses on category scales. However, if the number of categories on the response scale is increased, the degree of separation between the mean responses obtained for a positively as opposed to a negatively skewed concentration distribution diminishes. The present study investigates the effect of skewed concentration distributions upon ratings on a line scale and compares it to the context effect found for a 7-point category scale. In addition, sequential dependencies between consecutive stimuli and responses are investigated in order to assess their relevance in taste-intensity scaling studies. The context effects are similar for the 7-point category scale and for the line scale. The analyses of sequential effects show that both preceding responses and preceding stimuli affect current responses. However, since these two factors work in opposite directions, only a small contrast effect from the previous stimulus is significant in an overall analysis. The present study shows that even though the overall sequential effects between consecutive stimuli and responses are small, the effect of experimental context may be considerable. Since subjective context is established at the beginning of a session and sequential dependencies operate throughout the whole session, it is argued that contextual and sequential effects are only indirectly related.

Adult↗
PubMed1989

Individual gustatory reaction times to various groups of chemicals that provoke basic taste qualities.

Reaction times (RTs) to four groups of substances that provoke different taste qualities were measured. Measurements for all substances with the same taste, equalized in perceived intensity and provoking a very strong taste, were made concurrently for each subject. The comparisons were made on the individual level. No significant differences in RTs to substances with the same taste quality were found. When the factor of perceived intensity is kept constant, no effect of the stimulus chemical composition on RTs seems to be present. RTs to stimuli with different tastes differ significantly, the shortest being to salt and the longest to bitter. The difference in RTs for sour and sweet substances is small, and the subjects were not all alike in terms of the order of RTs with respect to these stimuli.

Humans↗
PubMed1991

The effectiveness of different sweeteners in suppressing citric acid sourness.

The exact mechanism that causes taste suppression in a perceptually heterogeneous mixture, and the locus of that mechanism, are as yet unknown. The present study was designed to explore the idea that mixture suppression is a perceptual phenomenon and not the result of physical, chemical, or receptor-substance interactions. An investigation was carried out as to whether perceptually similar taste stimuli give rise to the same sensory interactions when mixed with a substance of a different taste quality. In the first study, five different sweeteners (sucrose, fructose, aspartame, saccharin, and sorbitol) were matched in perceived sweetness intensity, in order to obtain five perceptually similar stimuli. Every equisweet sweetener concentration was mixed with each of four citric acid concentrations. In a second study, the sourness-suppressing effects of two sweeteners, sucrose and aspartame, were compared at four different concentration levels. Sourness scale values of unmixed citric acid, the unmixed sweeteners, and the citric acid/sweetener mixtures were assessed with a functional measurement approach in combination with a two-stimulus procedure. The equisweet sweeteners were equally effective in suppressing the perceived sourness intensity of citric acid over the concentration range used. The side tastes of the sweeteners, if present, did not have a substantial effect on the degree of sourness suppression.

Adult↗
PubMed1991

Reliability of magnitude matching.

In each of four experimental sessions, each of 16 subjects gave magnitude estimates of the taste intensities of NaCl and the loudness of noise on a single, common scale--the method of magnitude matching. In all sessions, the intensity levels of the noises were identical; but in two sessions, the concentrations of NaCl were low, and in two they were high. Cross-modality matches (magnitude matches) between NaCl and noise were derived from the judgments, revealing two main findings: First, given constant NaCl concentrations, individual subjects showed reliably different magnitude matches. Second, changing the NaCl concentrations (context) strongly affected the magnitude matches. These findings suggest that magnitude matching may be useful in assessing interindividual as well as intergroup differences, though caution must be taken to minimize effects of context: Context effects are pervasive; they suggest the presence of a complex relativistic process operating when people judge the intensities of qualitatively different stimuli.

Attention↗
PubMed1993

Response selection, sensitivity, and taste-test performance.

Tasters selected the odd stimulus from among sets of three samples of party dip. Two samples came from one batch, and one sample came from another batch. The physicochemical difference between the batches consisted of the presence or absence of added salt. Two different tests of discriminability were undertaken by the same subjects with the same stimuli: the triangle test and the three-alternative forced-choice (3-AFC) method. Although different numbers of correct selections were obtained in the two tasks, an index of discriminability, d', had the same value when the data were analyzed in accordance with the Thurstone-Ura and signal-detection models, respectively. The average data support Frijters's (1979b) contention that different models of the discrimination process are appropriate to the results of the triangular and the 3-AFC procedures. Further analysis of the data revealed that discrimination was poorer for trios containing one physicochemically weak stimulus and two stronger stimuli than it was for trios containing one stronger stimulus and two weak stimuli. A two-signal 3-AFC task was undertaken by some subjects, and d' estimates from this task were lower than expected on the basis of performance in the other tasks.

Adult↗
PubMed1993

Context effects in judging taste intensity: a comparison of variable line and category rating methods.

The effect of stimulus range and stimulus spacing was examined when subjects registered the perceived intensity of sweet liquids using either a matching procedure (Experiment 1) or category rating (Experiment 2). The matching procedure is conceptually similar to absolute magnitude estimation, whereby subjects match their impression of number size to their impression of the subjective magnitude of a stimulus. In Experiment 1, subjects matched their impression of the stimulus to their impression of the magnitude of the length of a continuously variable line under their control. In Experiment 2, subjects rated perceived sweetness on a vertical 13-point scale with five equally spaced verbal labels. In both experiments, three sets of four sucrose concentrations were employed. In two of these sets, a set of weaker solutions and a set of stronger solutions, concentrations were separated by 0.25 log units. In a third set, which spanned the range of concentrations used in the other two sets (0.87 to 27.36% w/v), solutions were separated by 0.5 log units. An examination of both individual and group data showed the matching procedure to be less susceptible to a range bias than the rating procedure. In particular, a single intensity function accommodated data from individual ranges better when the matching procedure was used than when the rating procedure was used. No effect of stimulus spacing was evident in the data from either procedure.

Attention↗