Definitions for "Weber's law"
the principle that the amount of change in stimulation needed to produce a just noticeable difference is a constant proportion of the original stimulus. (154)
a principle that seeks to explain the relationship between the size of a stimulus and the amount by which the stimulus must be increased or decreased for an individual to “just notice a difference;” a psychological law that attempts to quantify the minimum amount of change in a stimulus needed to produce a “just noticeable difference” in a person's mind. Much depends, of course, on the size of the stimulus in its initial state (e. g., the price level prior to a change). Can be expressed mathematically. Helps to shed light on questions related to how much must a product's price be lowered (or raised) for the consumer to just notice the price change or how many brands must a retailer add (or subtract) for the consumer to just notice there has been an increase (or decrease) in the store's assortment. In essence, whether it is a price change, a change in product attributes, or some other change, there is a threshold below which consumers do not recognize a difference and above which they do, and it really depends on the starting point and the magnitude of the change relative to that starting point. Named after E.H. Weber, a 19th century experimental psychologist.
(psychophysics) the concept that a just-noticeable difference in a stimulus is proportional to the magnitude of the original stimulus; "Weber's law explains why you don't notice your headlights are on in the daytime"