How does it feel to return to a place you have been to after so many years?

When I return to a place I have been to after so many years, I always feel particularly warm. Although the people living here are no longer the people I knew, the scenery remains the same. Standing in this place now, I can always miss the time we have experienced together in the past, and feel that time flies so fast.

After the intensity of the stimulus reaches a certain intensity, a sensation occurs. As the intensity of the stimulus increases to a certain level, the sensory system stops working normally. Any stimulation that exceeds a certain limit in intensity will cause pain and disrupt the normal activity of the sensory system. The range of sensory quantities from smallest to largest determines the range of susceptibility of a sensory system.

The minimum amount of stimulation that can just cause sensation is called the absolute sensory threshold, and the corresponding sensory ability is called absolute susceptibility. The two are inversely proportional to each other.

Examples of qualia

Quasi

The entire range of qualia (see picture). The absolute sensitivity of vision is extremely high. Under complete dark adaptation conditions, the energy of only a few photons can cause light perception, and vision can also experience extremely strong light. The same sensory channel is also not equally sensitive to different stimuli within a given range.

For example, the sensitivity of the human eye to light of different wavelengths in the spectrum is very different. They can differ by several orders of magnitude or several logarithmic units, so it is called the spectral light efficiency function, or spectral vision. The brightness function V(λ) is actually the relative sensitivity of the human eye to the spectrum.