Stevens law, also known as Stevens's power law or the power law of sensation, is a psychological principle that explains the relationship between the physical intensity of a stimulus and the perceived intensity or magnitude of the resulting sensation. It was proposed by the American scientist and psychologist, Stanley Smith Stevens, in the 1950s.
According to Stevens law, the relationship between the physical and perceived intensities of a stimulus is not linear but instead follows a power function. This means that as the physical intensity increases, the perceived intensity does not increase in a one-to-one fashion, but rather increases exponentially. The law states that the sensation magnitude is proportional to the physical intensity raised to a power.
Stevens law is often applied in psychophysics, a field that studies the quantitative relationship between physical stimuli and the corresponding human sensations or perceptions. It provides a mathematical model to understand how humans perceive different sensory stimuli, such as brightness, loudness, or pain intensity.
The power exponent in Stevens law determines the sensitivity of an individual to changes in stimulus intensity. For example, a smaller exponent indicates greater sensitivity to changes, whereas a larger exponent indicates less sensitivity. This law has significant implications in various areas, including the design of measuring instruments, understanding human perception, and developing marketing strategies that aim to elicit desired sensory experiences.
