| Citation | John Robson is distinguished for his many contributions to vision science. His careful measurement and analysis of the visibility of sinusoidal gratings and other periodic stimuli first led him to propose the entirely novel hypothesis that the visual system comprises many spatial-frequency selective mechanisms, or filters, operating in parallel. His subsequent psychophysical studies characterised the bandwidth of these filters while his neurophysiological investigations of the responses of retinal and cortical neurons not only showed how spatial-frequency selectivity was elaborated in these cells but also demonstrated how the Fourier-based experimental and analytical methods he had pioneered could provide new insights into the nature of visual processing. The seminal nature and importance of this work has been recognised by the Friedenwald award of the Association for Research in Vision and Ophthalmology and the Tillyer award of the Optical Society of America. He has demonstrated how the spatio-temporal interactions that he was the first to measure psychophysically can result from small differential delays in signal paths in the retina, and shown how non-linear interactions in the cortex can be understood in terms of a contrast-normalisation mechanism. With Laura Frishman he has used electroretinogram recordings to study retinal kinetics and the retinal loci of light adaptation, and with Denis Pelli he has devised an eye-testing chart that is now widely used in clinical measurement of contrast sensitivity. |