Final answer:
The smallest difference in stimuli that can be detected is known as the difference threshold or just noticeable difference (JND). It refers to the minimum amount of difference in stimulus energy required to be detected about 50% of the time.
Step-by-step explanation:
Smallest Difference in Stimuli
The smallest difference in stimuli that can be detected is known as the just noticeable difference (JND) or difference threshold. It refers to the minimum amount of difference in stimulus energy required to be detected about 50% of the time. The JND can vary depending on the intensity of the stimulus. For example, in a dark movie theater, a small change in the brightness of a cell phone screen would be noticeable, whereas in a brightly lit arena, the same change may go unnoticed. This concept was proposed by Ernst Weber in the 1830s and is known as Weber's law.