What refers to the minimal difference between two stimuli that can be reliably detected?

The term that describes the minimal difference between two stimuli that can be reliably detected is known as the difference threshold, often referred to as just noticeable difference (JND). This concept highlights how individuals perceive slight variations in stimuli, emphasizing that it's not just the existence of a stimulus that matters, but also the ability to notice changes between similar stimuli.

For example, if you are holding a weight, the difference threshold pertains to the smallest amount of added weight that you can notice. This threshold can vary based on several factors, such as the intensity of the initial stimulus and the individual’s sensory capabilities.

In contrast, the absolute threshold refers to the minimum intensity of a stimulus that is needed for it to be detected 50% of the time, meaning it focuses on the presence of a stimulus rather than differences between stimuli. Perceptual threshold and sensitivity threshold are not primarily terms used in standard psychology discussions regarding the detection of differences in stimuli and therefore do not accurately reflect the established terminology surrounding sensory perception.