Physicist’s View of Vision

Abstract

Visual mechanisms of animals are extremely complex, but, as a physicist, I shall treat them perhaps a bit simplistically. I shall start with two central questions: What is the function of our visual system, and what are the mechanisms by which it works? A little bit of natural history will be useful to begin to answer the first question. In the jungles of South America there is a strange species of jumping spider. The female has on her posterior a red mark in the form of a “V.” The retina of the male is also in the form of a “V.” When the male, wandering through the forest, notices an object of the right dimensions, and recognizes a brilliant red V, he knows he has found a mate. If the V is lacking, he knows it is only an opportunity for a good meal. His visual system is specially designed to fit his needs.