The Effects of Bitter-Adaptation on Sensitivity to the Other Taste-Qualities

This study deals with the effect that adaptation to bitter has on sensitivity to the other taste-qualities; sweet, salt, and sour. The reason for investigating this special problem is that, while all taste-qualities are known to undergo adaptation, the character of the after-effects of adaptation is less well established for bitter than for the other primary qualities. The history of the problem reveals a confusion of terminology as well as a disagreement among the experimental results. The facts of tasteadaptation have been confused with those of taste-contrast, with the consequence that the meaning of the term 'contrast,' so far as the sense of taste is concerned, has become ambiguous. The confusion is surprising, for the differences between adaptation and contrast are clear and unmistakable. The phenomena of contrast in taste are akin to those of vision and result from the distribution of taste-stimuli over the tongue; for example, salt applied to one side of the tongue may bring out the taste of a subliminal sour or sweet applied to the other side. Thus the contrast-effect in taste may be defined as the effect that spatially distributed tastes, either simultaneously or successively presented, have upon one another.