psychophysics essays

psychophysics essays The Weber -Fechner Principle: An Approximate psychological law relating the degree of response or sensation of a sense organ and the intensity of the stimulus. The law asserts that equal increments of sensation are associated with equal increments of the logarithm of the stimulus, or that the just noticeable difference in any sensation results from a change in the stimulus, which bears a constant ratio to the value of the stimulus. Weber was the first German anatomist and physiologist to introduce the concept of the just-noticeable difference, which is the smallest observable difference between two similar stimuli. From 1818 until 1871 Weber was a professor at the University of Leipzig. Weber is best known for his work on the sensory response to weight, temperature, and pressure. Weber stated that, in order for any increase in the intensity of the stimulus a threshold of sensation must be passed. This increase would create the just-noticeable difference. The ratio Weber discovered was the total intensity of sensation, rather than an absolute figure. Greater weight had to be added to heavier objects in order for the person to notice the change. Weber's observations were formed mathematically by Gustav Theodor Fechner, which he later called Weber's law. Fechner was a German physicist and philosopher; he was an influential figure in the development of psychophysics. He was concerned with the quantitative relations between sensations and the stimuli producing them. When Fechner was 16, he began medical school at the University of Leipzig where he studied anatomy under Weber. Fechner upon graduation discovered his interested lead more toward physics and mathematics than medicine. Fechner by the end of the 1830's had written several papers on the perception of complementary and subjective colors. In 1840 his article on subjective afterimages w ...