Perceived intensity grows as a power function of stimulus intensity, with an exponent specific to each sense.
Stevens's 1957 refinement of Weber-Fechner. The exponent varies: brightness compresses, and electric shock expands, which is why pain scales behave so differently from loudness scales.
In practice
- Doubling a bulb's wattage does not look twice as bright; doubling the current in a shock feels far more than twice as bad.
- A pain scale behaves nothing like a loudness scale, which is why "rate it out of ten" means different things in different domains.
- Standing
- Refines the earlier Weber–Fechner logarithmic account.
- Further reading
- Wikipedia
- Subject
- Psychology & Behavior
- Essay
- A century and a half of measuring the mind