Chapter 4: Sensation and Perception Study Guide ? Absolute Threshold: The minimum stimulus intensity that an organism can detect for a specific type of sensory input. Just Noticeable Difference (JND): The smallest difference in stimulus intensity that a specific sense can detect. The JND is a constant proportion of the size of the initial stimulus. Subliminal: ?Below Threshold? Subliminal Perception: The registration of sensory input without conscious awareness. Signal Detection Theory: The detection of stimuli involves decision processes as well as sensory processes, which are both influenced by a variety of factors besides stimulus intensity. Hits: Detecting signals when they are present. Miss: Failing to detect signals when they are present.