Ernst Heinrich Weber (24 June 1795 – 26 January 1878) was a German physician who is considered one of the founders of experimental psychology. He was an influential and important figure in the areas of physiology and psychology during his lifetime and beyond. His studies on sensation and touch, along with his emphasis on good experimental techniques led to new directions and areas of study for future psychologists, physiologists, and anatomists. Ernst Weber was born into an academic background, with his father serving as a professor at the University of Wittenberg. Weber became a doctor, specializing in anatomy and physiology. Two of his younger brothers, Wilhelm and Eduard, were also influential in academia, both as scientists with one specializing in physics and the other in anatomy. Ernst became a lecturer and a professor at the University of Leipzig and stayed there until his retirement. Early life Ernst Heinrich Weber was born on 24 June 1795 in Wittenberg, Saxony, Holy Roman Empire. He was son to Michael Weber, a professor of theology at the University of Wittenberg. At a young age, Weber became interested in physics and the sciences after being heavily influenced by Ernst Chladni, a physicist often referred to as the “father of acoustics”. Weber completed secondary school at Meissen and began studying medicine at the University of Wittenberg in 1811. He went on to receive his MD in 1815 from the University of Leipzig. The fighting and the aftermath of the Napoleonic wars forced Weber to relocate from Wittenberg. He became an assistant in J.C. Clarus’ medical clinic in Leipzig in 1817 and then a professor in comparative anatomy in 1818 at the University of Leipzig. He became chair of human anatomy at the university in 1821. Ernst Weber’s first direct contribution to psychology came in 1834 when trying to describe the sensation of touch (De Pulsu, Resorptione, Auditu et Tactu. Leipzig 1834). Contributions Just-Noticeable Difference Weber described the just-noticeable difference or jnd as follows: “in observing the disparity between things that are compared, we perceive not the difference between the things, but the ratio of this difference to the magnitude of things compared.” In other words, we are able to distinguish the relative difference, not the absolute difference between items. Or, we can distinguish between stimuli having a constant ratio, not a constant difference. This ratio is known as the Weber fraction. Weber’s first work with the