Task-determined strategies of visual process, by Gad Geiger, Jerome Y. Lettvin, and Olga Zegarra-Moran.
What the Frog's Eye Tells the Frog's Brain, by J. Y. Lettvin, H. R. Maturana, W. S. McCulloch, and W. H. Pitts
Just read I.A and VIII, about 2 pages, to get the flavor of what Lettvin discovered about frogs.
A more recent treatment
Developmental Dyslexia: a Different Perceptual Strategy and How to Learn a New Strategy for Reading, by Gad Geiger and Jerome Y. Lettvin.
An amazing auditory result
Wide and Diffuse Perceptual Modes Characterizes Dyslexics in Vision and Audition, by Gad Geiger et al.
WRT: 1 hour, but Section 3, readable in minutes, is the interesting part