Answer:
The just noticeable difference.
Explanation:
Sensitivity to differences in intensity levels not constant or the smallest difference in the amount of simulation that a specific sense can detect.
It is clearly stated here that intensity level of the stimulus can also play a role in how much people notice changes. If a light is very, very dim, people might be more likely to notice smaller changes in intensity than they would if those same changes were made to brighter light.
