What does Rico's Law state about photons for a stimulus?

Rico's Law pertains to the relationship between light intensity, area, and total photon count. It indicates that when the area over which light is spread remains constant, the total number of photons for a stimulus within that area also remains constant. This means that as long as the area does not change, the overall amount of light energy, as measured by the number of photons, does not fluctuate, assuming the light source maintains a consistent intensity.

This principle is significant in understanding how we perceive light and visual stimuli, as it relates to the distribution of light across a given surface. The fixed relationship reinforces the concept that with a stable light source and area, we can predictably assess the photonic energy available for stimulating visual receptors.