What term describes the weakest amount of stimulus that a person can detect half the time?

The term that describes the weakest amount of stimulus that a person can detect half the time is known as the absolute threshold. This concept is fundamental in the field of psychophysics, which studies the relationship between physical stimuli and the sensations and perceptions they affect. The absolute threshold represents the point at which a stimulus is strong enough to be detected at least 50% of the time. For example, this might refer to the minimum volume of a sound that can be heard or the faintest light that can be seen.

In contrast, other concepts like the difference threshold, also known as just noticeable difference (JND), refers to the smallest change in stimulus intensity that can be detected. Signal detection theory focuses on how we distinguish between signal (stimulus) and noise (background stimuli) in various contexts, particularly considering the influence of contextual factors like motivation or expectations. Lastly, subliminal perception pertains to stimuli that are below the conscious threshold of awareness, which means they are not detected even if they are present. These distinctions are critical in understanding sensory processing and perception in psychology.