The judgment operation of ratio production

The judgment operation that individuals perform when they set a sensory intensity in a predefined ratio to a standard sensory intensity is unknown. The present study was conducted to determine this operation by functional measurement. Participants first produced a sensory intensity for each combination of various predefined ratios and standard sensory intensities. Subsequently, they rated these produced intensities. Factorial graphs derived from these ratings were essentially parallel. This result shows that participants produced each sensory intensity by operating as if they were adding an amount of sensory intensity to the respective standard sensory intensity. It was found that this added amount varied nonlinearly with the predefined ratio, implying that ratio productions are nonlinear.