Ernst Weber Anatomist and physiologist Date of Birth: 24.06.1795 Country: Germany

1. Biography of Ernst Weber
2. Early Life and Education
3. Professional Career
4. Weber's Contributions to Psychology and Physiology
5. Ernst Weber passed away on January 26, 1878, in Leipzig.

Biography of Ernst Weber

Ernst Weber, an anatomist and physiologist, is considered one of the founders of experimental psychology. His research on sensations and touch, along with the application of rigorous experimental methods, led to the emergence of new directions and areas of study for future psychologists, physiologists, and anatomists.

Early Life and Education

Ernst Heinrich Weber was born on June 24, 1795, in Wittenberg, Saxony, Holy Roman Empire. He was the son of Michael Weber, a theology professor at the University of Wittenberg. From an early age, Ernst developed a keen interest in physics and natural sciences, greatly influenced by the "father of acoustics," physicist Ernst Chladni. He studied medicine at the University of Wittenberg starting in 1811 and obtained his doctoral degree in 1815 from the University of Leipzig.

Professional Career

Due to the aftermath of the Napoleonic Wars, Ernst had to leave his hometown. By 1818, he became a professor of comparative anatomy at his alma mater. In 1834, he made his first contribution to anatomy while attempting to describe cutaneous sensitivity. In his work on the "just noticeable difference" and the sensory threshold, Weber wrote: "Observing the discrepancy between the things being compared, we perceive not the actual difference between the things, but the ratio of this difference between the things being compared." In other words, we are capable of discerning the relative difference between two elements, rather than the absolute difference.

Weber's first work on the threshold of discrimination was related to differences in weight. He determined that the best discrimination occurs when the chosen weight differs from the other by 8-10%. For example, if you hold a 100g block, the second block should weigh at least 103g for you to perceive the difference. Weber also suspected that there are differential thresholds of discrimination for all sensory organs. For example, in order for the human ear to detect a difference in sound pitch, there needs to be a difference of at least 0.006 vibrations per second.

Weber's Contributions to Psychology and Physiology

Weber's empirical psychophysical law, known as Weber's Law or Fechner's law, states that the intensity of sensation is directly proportional to the logarithm of the intensity of the stimulus. However, in the 20th century, American psychologist Stanley Stevens proposed using a power law to describe the relationship between stimulus strength and sensation, demonstrating the limitations of Weber's Law.

Throughout most of his career, Weber collaborated with his brothers, Wilhelm Eduard Weber and Eduard Friedrich Weber, as well as his partner Gustav Theodor Fechner. Their collaboration helped Ernst complete studies on the central nervous system, auditory system, and functions of the brain, as well as the circulatory system, and more. Much of their research focused on sensory physiology and psychology.

In 1821, Ernst conducted a series of experiments on fluid dynamics along with his younger brother Wilhelm. The brothers observed the nature of water particle movement when waves traveled across the water's surface. This experiment helped them develop a detailed account of hydrodynamic principles in blood circulation. In 1827, Ernst shed light on the elasticity of blood vessels by studying blood flow from the aorta to the capillaries in a continuous stream.

Weber also developed methodologies and devices for experimental investigation of sensory organs while studying the differential threshold of stimulation between two adjacent points on the body. He invented an aesthesiometer, also known as "Weber's compass," to determine the threshold of cutaneous sensitivity. By increasing the distance between the two points of contact with the skin, Weber determined at what distance the stimulation would be perceived as two separate points. He concluded that different areas of the skin have different sensitivities. For example, it was found that in the lumbar region of the back, even at a distance of 1.5cm between the points of contact, they often cannot be distinguished as separate. The thermal illusion, which arises from the activation of cold cutaneous mechanoreceptors, is known as the "Weber illusion." Ernst noticed that cold objects seem heavier than equally weighted warm objects.

Weber's use of multifactorial experiments, precise measurements, and his research in sensory psychology and sensory physiology laid the foundation for the acceptance of experimental psychology and psychophysics as distinct fields.

Ernst remained a professor of anatomy at the University of Leipzig for many years, only becoming a professor of psychology towards the end of his life. He retired from the university in 1871. He continued to collaborate with his brother Eduard, and in 1845, they discovered the inhibitory influence of the vagus nerve on heart activity, laying the foundation for the understanding of inhibition as a distinct physiological phenomenon.

Ernst Weber passed away on January 26, 1878, in Leipzig.

Weber's name is associated with the "Weberian apparatus," sensory organs found in certain bony fish that allow them to gauge the degree of inflation of their swim bladder with gas. Weber described this apparatus in 1820.

Weber's meticulous notes and innovative testing ideas in his book "Der Tastsinn und das Gemeingefühl" (The Sense of Touch and the Common Sensibility) prompted the Anglo-American experimental psychologist Edward Bradford Titchener to refer to this work as the "cornerstone of experimental psychology."

Another book by Weber, "Wellenlehre, auf Experimenten gegründet" (Wave Theory, Founded on Experiments), was instantly recognized as important for both physics and physiology.

While most psychologists of that time conducted their work from behind a desk, Weber actively conducted experiments, manipulating only one variable at a time to obtain more accurate results.