Webber's law, Fechner's law and Stevens' law
Weber's Law
Weber, in the early 19th century, discovered that for a person lifting weights in an experiment, the just distinguishable additional weight depended [somehow] on [what?]. In other words, if the original weight is
Fechner's Law
Fechner wished to derive a transformation that would transform the physical intensity scale to a "perceptual scale" where units on the perceputal scale corresponded to perceptual changes of the same magnitude.
Fechner started with two assumptions:
- Weber's law was valid.
- A just noticeable difference can be considered a [what?].
Stevens' law
Stevens showed that many relationships between just noticable differences and physical stimulus changes actually follow a [something] law. Steven's work finds its way into some fundamental aspects of color measurement.