MENTAL MODEL · M4234

Stevens' Power Law

BehaviorHigh supportPsychology

Included

Version 1.0.0 · Updated 2026-07-30

CORE DEFINITION

Perceived intensity is a power function of physical stimulus intensity, not a linear relationship. Different sensory modalities have different power exponents (e.g., electric shock > pain > brightness).

SCAFFOLDING EFFECT

psychology

Reduce cognitive load

Provides a quantitative framework for perceptual nonlinearity. In user experience design or risk communication, it explains why "doubling the dose" does not always lead to "doubling the sensation," helping us more precisely match stimuli to expected responses.

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In psychophysics, the perceived magnitude ψ is related to the physical magnitude φ by a power function ψ = k·φ^β, where β varies by sensory modality (pain β>1 is superlinear, brightness β<1 is sublinear). That is, doubling the stimulus does not double the sensation, and the direction of deviation depends on the modality.

MINIMUM ACTION

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Practice this model in one real situation:

For design or communication: 1) Determine the β for the target sensory modality
Use nonlinearity to match stimuli to expectations
Be cautious with increasing stimuli for superlinear modalities (e.g., pain)
For sublinear modalities (e.g., brightness), larger changes are needed to be noticeable
Calibrate with data.

Check to track your progress (stored locally)

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Source support: Explicit

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en.wikipedia.orghttps://en.wikipedia.org/wiki/Stevens%27s_power_lawZH · Explicit
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