The difference threshold, also known as the just noticeable difference (JND), refers to the minimum amount of change in a stimulus that can be detected by an observer. This concept is crucial in fields like psychology and sensory perception, as it helps to understand how we perceive changes in our environment. For example, if you are holding a weight, the difference threshold determines how much additional weight you need to feel a noticeable difference. This threshold varies depending on the type of stimulus and the initial intensity. According to Weber's Law, the difference threshold is proportional to the original stimulus intensity. For instance, if you are in a dimly lit room, a small increase in light may be easily noticed, while in a brightly lit room, the same increase might go unnoticed.