Gustatory reaction time under variable stimulus parameters in human adults

Abstract

Reaction times and perceived intensities for NaCl solutions were measured in sixteen human adults. Stimulus delivery was by means of a circular piece of solution-soaked filter paper held with forceps. The reaction time (T) decreased and the perceived intensity (S) increased with increasing the concentration (C) of NaCl solution applied to a fixed (78.5 mm 2) tongue area. The comprehensive relations among T, S and C can be expressed by the following formulae; T = a + b log( C C 0 ) , T = p + q log( S S 0 ) , and logS = mlogC + logn, where a, b, p, q, m, n = constants, and S 0 indicates the perceived intensity at the threshold concentration (C 0). Meanwhile, the reaction time decreased and the perceived intensity increased with increasing the stimulated area (A) under a fixed (1.0 M) concentration of NaCl solution. The relations among T, S and A can also be expressed by the following equations; T = a′ + b′ log( A A 0 ) , T = p′ + q′ log( S S 0 ) , and logS = m′logA + logn′, where a′, b′, p′, q′, m′, n′ = constants, and A 0 indicates the threshold size of stimulated area.