Direct magnitude estimation of salt taste intensity with continuous correction for salivary adaptation

Subjects sipped and expectorated NaCl solutions, estimating intensities by direct magnitude estimation, with and without interstimulus rinsing, while saliva samples were taken prior to each tasting and analysed for sodium. Interstimulus rinsing was seen to reduce salivary sodium concentrations and elicit higher intensity estimates. Exponents for simple psychophysical power functions were seen to be higher in the no-rinsing condition, confirming earlier studies. When the functions were corrected for adaptation level and chemical activity, the trend in exponents was reversed; this can be interpreted in terms of context effects. It was also found that power functions only produced the best fit for approximately half the functions; parabolic functions produced approximately half, while a few were best fitted by exponential, linear and logarithmic functions.