Method of stimulation, mouth movements, concentration, and viscosity: Effects on the degree of taste adaptation

Although sensory adaptation, the gradual loss of sensation during prolonged stimulation, has been demonstrated in laboratory taste experiments, a comp arable loss of taste intensity is not experienced in real-life eating situa tions. This discrepancy may be due to differences in the proximal stimuli o r to differences in the ways the taste receptors are stimulated. In two exp eriments, the effects of four potentially relevant variables were investiga ted: stimulus intensity, stimulus viscosity, mouth movements, and presentat ion method. During the initial seconds of stimulation, adaptation to the we akest of the two solutions was faster. Although more viscous stimuli were l ess sweet, viscosity as such did not affect adaptation rate, nor did mouth movements. Among the three presentation methods, a sucrose-soaked filter pa per on the tongue produced more adaptation than either sipping the solution or flowing it over the tongue. This suggests that even mouth movements far more subtle than those still present in the no-movement condition of a sip -and-spit experiment can disrupt the adaptation process.