Relation between the differential threshold for intensity and the intensity level of the stimulus:
~ Ex.: DT : 2 units with intensity level of the stimulus = 10 units
What happens when the intensity level of the stimulus is 20, 30, 50, …?
Below is a plot of some hypothetical data showing Weber’s Law.
The slope of the line is the Weber Fraction:
Whether the stimulus is applied to eye, skin, nose, tongue or other senses there is a lawful relationship between the size of the difference threshold and the stimulus intensity level.
Valid for a range of stimulus intensities, it’s a good baseline to compere performance.
But it’s not always true ⇒ increase greatly at extremely low stimulus intensities.