Weber experimentally determined the accuracy of tactile sensations, namely, the distance between two points on the skin, in which a person can perceive two separate touches. He discovered the two-point threshold - the distance on the skin separating two pointed stimulators that is required to experience two rather than one point of stimulation.
In 1834 he conducted research on the lifting of weights. From his researches he discovered that the experience of differences in the intensity of sensations depends on percentage differences in the stimuli rather than absolute differences. This is known as the just-noticeable difference (jnd), difference threshold, or limen.
Similar observations were made on other senses, including sight and hearing.
He formulated the Weber's law:
(ΔI/I = k - constant),
where I is the original intensity of stimulation,
ΔI is the addition to it required for the difference to be perceived,
and k is a constant is known as Weber's constant.
For lifting weights, the ratio was one to 40. That is, for any standard unit of 40, subjects would notice a difference if one more unit were added to the weight.
The constant is different for each sense (for intensity of light-1/100, sound -1/10).
Weber also described a absolute threshold for all senses, is the smallest detectable level of a stimulus.
Weber’s works was considered by the English-American psychologist Edward Titchener to be “the foundation stone of experimental psychology.”
Especially important was his transfer of experimental methods of physiology in the psychology field.
In 1818 he was appointed Associate Professor of comparative anatomy at Leipzig University, where he was made a Fellow Professor of anatomy and physiology in 1821. Weber was a professor at the University of Leipzig from 1818 until 1871.
In 1821 he was the chair of human anatomy which in 1840 was joined with physiology and in 1865 chair of physiology relinquished to Carl Ludwig.
Around 1860 Weber worked with Gustav Fechner on psychophysics, during which time he formulated Weber's Law.
He devoted his life to science and research.