Tasting successive salt and water stimuli: the roles of adaptation, variability in physical signal strength, learning, supra- and subadapting signal detectability

When NaCl (S) and water (W) are tasted in random order, the two stimuli can be tasted in four possible paired sequences; these orders give stimulation of different signal strengths which are, in decreasing order: W–S, S–W, W–W, S–S. These signal strengths were explained by adaptation effects and by hypotheses generated from experiments examining the variation in concentration of a stimulus once it is placed in the mouth, the effects of stimulus learning and differences in distinguishability of supra- and subadapting stimulation.