Floyd Ratliff
The Rockefeller University
May 1, 1919 - June 13, 1999
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Scientific Discipline: Psychological and Cognitive Sciences Membership Type:
Emeritus
(elected 1966)
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Floyd Ratliff investigated the spatial and temporal characteristics of visual perception. His studies on the effects of eye movement on vision led to the creation of a device that stabilized retinal images (the non-movement condition), allowing for the control of the temporal aspects of contoured visual stimuli. Techniques he developed to explore brightness discrimination in pigeons have been extended to measure visual and auditory thresholds in several animal species. Working concurrently with Hartline, Ratliff conducted his most significant research on the linear optical system of Limulus (the horseshoe crab). This study became the first quantitative description of information processing in a portion of the nervous system, as well as the first use of computerized data collection in neurophysiology. It was from this research that Ratliff discovered the process of disinhibition, a basic principle of neural organization. He used this to principle to define the properties involved in the interaction of individual neural elements in the retina. He demonstrated that the entire retina, not just a region, was comprised of a neural network within several other networks. He then worked to interpret brightness contrasts, the visual phenomenon of Mach bands, border contrast, and other related phenomena in human pattern vision. These findings were summarized in his 1965 publication, "Mach Bands: Quantitative Studies on Neural Networks in the Retina", which was considered a major influence on the development of the field of sensory physiology. Ratliff’s other major contributions included determining the dynamics of excitation and inhibition in retinal networks using Fourier analyses and developing the application of evoked potential methods to assess visual disorders.
Ratliff received his BA in psychology from Colorado College in 1947. For his graduate studies, he enrolled at Brown University, earning both his MS and PhD in physiological psychology in 1949 and 1950, respectively. He began teaching at Harvard University the following year, becoming an assistant professor in 1952. He left Harvard in 1954 to accept a position as an associate in biophysics at The Rockefeller Institute (now The Rockefeller University). In 1966, he was appointed the professor of biophysics and physiological psychology at the newly named Rockefeller University, and he held the position until becoming a professor emeritus in 1989. From 1974 to 1986, he served as the Head of the Laboratory of Biophysics. He also was the president of the Harry Frank Guggenheim Foundation from 1983 to 1989. Ratliff was a member of numerous organizations, including the Society for Neuroscience, the American Psychological Society, the Society of General Physiologists, the Society of Experimental Psychologists, and the Optical Society of America. For his work in retinal mechanisms, he was awarded the Edgar D. Tillyer Award from the Optical Society of America in 1976, the Pisart Vision Award from the New York Association for the Blind in 1983, and the Distinguished Scientific Contribution Award from the American Psychological Association in 1984.
