RATIO SCALES AND CATEGORY SCALES OF ODOUR INTENSITY

The relation between a ratio scale obtained by magnitude estimationand a category scale of the odour intensity of 1-butanol wasstudied, together with individual variations in the ratio scale.Series of solutions of butanol in water in small bottles werepresented to a panel for judgement, half using the method ofmagnitude estimation, the other half a category scale. Plotswere made of the category scale against the ratio scale, andthe ratio scales of individual members of the panel were analysed.A power function exponent of 0.48 was found for the panel'sratio scale, with individual values ranging from 0.25 to 0.49.The category scale was curved relative to the ratio scale; variabilityof the magnitude estimates was approximately proportional tothe magnitude estimates; and a small time-order error was found.Odour intensity exhibits the three tested characteristics ofa prothetic continuum, and the variability of individual exponentswas not as great as sometimes suggested.