What is the Weber-Fechner Law?

Also known as the law of sensory perception, it defines that the sensory solution to external stimuli (temperature, light, sound, etc.) is not proportional to the intensity of the stimulus. When the intensity of the stimulus is very great, the human senses self-regulate to perceive only huge differences; if the intensity of the stimulus is very low then they adapt to amplify the smallest possible differences. In marketing, it means that the consumer does not always perceive a variation in the price of a product or service. It depends on the magnitude of the change. In user experience, it provides information, for example, on response times in user interactions with systems.