Aging is associated with increased Weber ratios

Abstract

To investigate whether age-associated changes in the human taste system are quality-specific, we compared young and elderly subjects' suprathreshold discrimination abilities for caffeine and sucrose. The method of constant stimuli was used to obtain just noticeable differences and Weber ratios. The elderly generated larger Weber ratios than did the young for both the medium and high concentrations of caffeine, but not for the low concentration. For example, a 74% increase in .005M caffeine was required to obtain a perceptible difference for the elderly, whereas a 34% increase produced a perceptible difference for the young. The Weber ratios for sucrose did not differ for the two age groups. The results of this study indicate that age-associated changes in the taste system are quality-specific. 555We wished to know whether impairment in the ability \ to discriminate just noticeable differences (INDs) Investigations of psychophysical functions, recognition thresholds, and detection thresholds for taste in the elderly demonstrate age-associated impairment (see Murphy, 1986, in press, andSchiffman, 1986, for reviews) and suggest the additional hypothesis that the effects of aging on the taste system may be quality-specific (Bartoshuk, This research was supported by Grant AG04085 from the National Institute on Aging to Claire Murphy. We are grateful to James Brown, for his comments on an earlier version of the manuscript, and to Jill Sniffen, Kim Malloy, and Diane Bodge for their gracious assistance in testing subjects. Magdalena M. Gilmore (formerly Jensen) is now at the Department of Psychology, Brown University, Providence, RI. Correspondence may be addressed to Claire Murphy, Department of Psychology, San Diego State University, San Diego, CA 92182-0551. Rifkin, Marks, & Bars, 1986; Cowart, 1983, in press;Hyde & Feller, 1981;'Murphy & Gilmore, 1989;Spitzer, 1988;Weiffenbach, Baum, & Burghauser, 1982;Weiffenbach, Cowart, & Baum, 1986). When we determined psychophysical functions for stimuli representative of the four basic taste qualities in a previous study (Murphy & Gilmore, 1989), the elderly's intensity estimates of bitter were the most depressed relative to young people's estimates, and their intensity estimates of sweet were the least depressed. Therefore, tastants representative of these two taste qualities were examined in the present study, and we hypothesized that larger age differences would be found in the discrimination of bitter, as opposed to sweet, stimuli.Thus, the present study addressed two questions. First, do elderly individuals require a greater increase in the concentration of a suprathreshold stimulus in order to experience a perceptible difference in taste sensation than young subjects do? Second, does the size of the Weber ratio depend not only on age, but also on the stimulus tested? METHOD SubjectsThe participants were 12 females, 67-77 years of age (M = 72.42, SD = 3.20), and 12 females, 18-25 years of age (M = 22.92, SD = 1.51). All of the elderly subjects were active, communitydw...

The Effect of Barium on Perceptions of Taste Intensity and Palatability

“…Overall, only three samples (nonbarium water, nonbarium sucrose, and barium sucrose) were liked by subjects, as indicated by positive mean palatability scores. These data are consistent with previous evidence that sweet taste tends to elicit a greater pleasure response than other taste qualities across the human lifespan [61–64], apparently even in the presence of barium. Higher refusal rates for barium samples reinforced the palatability score results, in that the samples with the lowest palatability scores tended to be most frequently refused.…”

Quantification of sensory difference thresholds for fat and sweetness in dairy-based emulsions

“…When using aqueous solutions with a sucrose concentration of 3 and 6 g/100 g, the response of our panel resulted in k = 0.060 and k = 0.057 (no vanilla flavor), and in k = 0.057 and k = 0.062 (with vanilla flavor), respectively. These fractions are close to those presented by Lundgren, Pangborn, Barylko-Pikielna, and Daget (1976) and Berg, Filipello, Hinreiner, and Webb (1955), whereas about twice as high Weber fractions for sucrose sweetness have been published by, e.g., Gilmore and Murphy (1989), McBride (1983) and Laing et al (1983). Weber ratios for sucrose sweetness in water as low as 0.075 have also been quantified for nonhuman primates (Laska, Scheuber, Carrera Sachez, & Rodriguez Luna, 1999).…”

Ageing and taste

“…Seventeen studies found taste-identification thresholds to increase with age, although one study reported only a weak relationship between age and taste strip results (52) . Only one study found no significant difference between age groups (53) ; however, their older group was younger than in all other studies reported in this review (age [51][52][53][54][55][56][57][58][59][60][61][62][63][64][65], and therefore outside of our inclusion criteria. (27) 18 34 37 65-78 55-65 ME NaCl, SU (6) NaCl P < 0 .…”