Determination of saltiness from the laws of thermodynamics - Estimating the gas constant from psychophysical experiments

One can relate the saltiness of a solution of a given substance to the conc entration of the solution by means of one of the well-known psychophysical laws. One car also compare the saltiness of solutions of different solutes which have the same concentration, since different substances are intrinsic ally more salty or less salty. We develop here an equation that relates sal tiness both to the concentration of the substance (psychophysical) ard to a distinguishing physical property of the salt (intrinsic). For a fixed stan dard molar entropy of the salt being tasted, the equation simplifies to Fec hner's law. When one allows for the intrinsic 'noise' in the chemoreceptor, the equation generalizes to include Stevens's law, with corresponding decr ease in the threshold for taste. This threshold reduction exemplifies the p rinciple of stochastic resonance. The theory is validated with reference to experimental data.