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.     

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, andn-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.     

Psychological skills and mindfulness training effects on the psychological wellbeing of undergraduate music students: An exploratory study

This study explored the efficacy of psychological skills and mindfulness training intervention on the psychological wellbeing of undergraduate music students. Participants were undergraduate music students (n = 36) from the Department of Music at a South African university, 21 of whom were elected to take the psychological skills and mindfulness training intervention. Data on their self-reported psychological wellbeing, psychological skills, mindfulness and performance anxiety levels were collected pre-and post-intervention. The analysis applied non-parametric procedures to determine changes in students’ psychological wellbeing after the seven-week intervention programme. Findings suggest improvements in psychological wellbeing, psychological skills, mindfulness and performance anxiety with training. Psychological skills and mindfulness training may have benefits to the psychological wellbeing of music students.