The absolute threshold is the minimum level of stimulus intensity needed for a person to detect a particular sensation 50% of the time. This concept is crucial in fields like psychology and sensory perception, as it helps to understand how we perceive different stimuli, such as light, sound, or taste. For example, in the case of hearing, the absolute threshold would be the faintest sound that an individual can hear. Similarly, for vision, it refers to the dimmest light that can be perceived. Understanding absolute thresholds aids in studying sensory systems and their limits.