Granit, Ragnar Arthur (1900-1991), was a Finnish-born Swedish researcher who studied the physiology (structure and function) of the eye. He shared the 1967 Nobel Prize for physiology or medicine with the American scientists H. Keffer Hartline and George Wald. The prize was awarded for their work on chemical and physiological processes in the eye.
Beginning in the 1920’s, Granit’s research focused on psychophysics, a branch of psychology dealing with the relations betwen physical stimuli and sensations. Granit used techniques for amplifying the small electrical impulses in the nervous system to study the physiology of the retina, the part of the eye that absorbs light rays. He also conducted many investigations into the responses of individual retinal cells to light of a variety of wavelengths and intensities. His investigations into the retina led to his dominator-modulator theory of colour discrimination. According to Granit, some optic nerve fibres (the dominators) respond to the whole spectrum of light, but others (the modulators) are colour-specific.
Granit also developed the recording of electroretinograms (ERG’s), charts of the electrical responses of the retina to light. Granit compared the ERG’s of various animals, in different light conditions. Granit’s later work focused on the role of sensory organs in the muscles called muscle spindles and tendon organs in the regulation, coordination, and control of muscle action. Other work conducted by Granit includes research into the spinal cord, the mechanisms of pain, and related questions of motor control and neurophysiology.
Ragnar Arthur Granit was born in Helsinki, Finland. He studied psychology and medicine at Helsinki University. In 1940, he went to Sweden and became professor of neuropsychology at Stockholm’s Karolinska Institute.
