Final answer:
The absolute threshold is the minimum stimulus energy needed to be detected 50% of the time, while the difference threshold is the smallest change in stimulus that can be detected. The difference threshold is context-dependent and follows Weber's law, which states that the just noticeable difference is a constant fraction of the original stimulus intensity.
Step-by-step explanation:
The concept of absolute thresholds and difference thresholds are fundamental in understanding sensory perception. An absolute threshold is the minimum amount of stimulus energy required to be detected 50% of the time, whether it be the dimmest light visible or the quietest sound audible. The difference threshold, also known as the just noticeable difference (jnd), refers to the minimum amount of change in stimulus energy required for a difference to be detected 50% of the time. This can be influenced by the stimulus intensity and the context in which the change occurs. One commonly cited illustration of the difference threshold is when a person is in a dark movie theater and a cell phone screen lights up, it is likely to be noticed due to the high contrast with the surroundings. Conversely, if the same screen illuminates in a bright arena, the change is less likely to be detected because of the lower contrast. This exemplifies how the difference threshold can vary significantly with the conditions of the surrounding environment, in accordance with Weber's law.