Answer:
Weber's Law
Step-by-step explanation:
Ernst Weber, a 19th century psychologist proposed that the size of the difference threshold ( ΔI ) appears to be related to initial stimulus ( I ) magnitude.
Weber's Law is related to the just noticeable difference or the difference threshold which is the minimum difference in stimulation that a person can detect half of the time.
The formula: ΔI/I = k ( where k signifies the constant proportion)
In order to really perceive a difference, the stimuli must differ by a constant proportion not amount.