What type of stimuli does Stevens' Power law specifically relate to?

Stevens' Power Law relates to the relationship between the magnitude of a stimulus and the perception of that stimulus. It particularly addresses how the perceived intensity of a stimulus varies as a function of its actual intensity, especially in the context of extremely intense stimuli. According to this law, the perceived intensity increases in a nonlinear fashion, meaning that as the intensity of a stimulus becomes stronger (for example, under conditions of extreme intensity), the perceived increase in intensity is less than proportional.

This law is typically employed in contexts where stimuli are strong enough to be reliably detected and perceived, leading to meaningful changes in perception. In contrast, while weak or moderate stimuli can show perceptual changes, they do not encapsulate the specific nonlinear relationship that Stevens' Power Law describes as effectively as extremely intense stimuli. Constant stimuli do not engage the variability required to demonstrate this power law relationship either, as they do not represent changing conditions that affect perception.

Thus, the focus on extremely intense stimuli is key to understanding how Stevens' Power Law quantifies perceptual experiences across different levels of sensory input.