Pair Comparison and Ascending Series NaCl Thresholds: Criterion and Residual Effects

Abstract

Ascending series detection and recognition thresholds, both with and without interstimulus water rinses, and pair comparison thresholds, with varied presentation order, were measured for NaCl. Thresholds were measured in situ against a normal salivary background and also after rinses with 60 mM and 1 M NaCl. Predicted changes in the level of adaptation of the taste receptors, due to NaCl concentration changes in the mouth, were seen to vary the measured thresholds. Ascending series thresholds without interstimulus rinses were highest of all, although they were reduced by rinsing. The order of presentation in pair comparison tests was seen to vary thresholds in a manner predicted by proposed adaptation levels. Effects were also noted which were due to criterion definition and language. The trends found in the present experiments were also found in the literature.