Scales of Subjective Viscosity and Fluidity of Gum Solutions

Subjective viscosity and fluidity of water soluble gums were investigated as a function of apparent physical viscosity (in poises), and as a function of the method of presentation. Subjective magnitude (S) appeared to grow as a power function of viscosity (P) with S=kPn, and the exponent n averaging about + 0.4 for subjective viscosity, and ‐0.4 for subjective fluidity. Stimuli appeared more viscous (and less fluid) when presented in narrow‐mouthed test tubes than in wide‐mouthed bottles. The growth rate of subjective magnitude, indexed by n, did not change, however, suggesting that the dynamics of subjective magnitude for viscosity and fluidity are independent of the presentation procedure.