Weber Fechner and Steven's Power law

The concept of Just Noticeable Difference was given by Weber where he explained that we will be able to perceive the difference in intensity of the stimulus depending on the original strength of the stimulus. For higher strengths of stimulus, a greater chnage in intensity of stimulus is required is required to notice the difference in intensities. 

Fechner took this concept and tried to explain the percieved intensity of stimulus vis a vis the strength of stimulus. But Fechner law was applicable to only very high and very low intensities of stimulus. Later this was modified by Steven who gave Power law to explain the percieved intensity of stimulus.


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