David Marr
(1945-1980)
David Marr was a British neuroscientist whose early work was a theory of the cerebellar cortex and later an explanation of visual information processing from the retina to the visual cortex.
His book
Vision: A computational investigation into the human representation and processing of visual information, was published posthumously by Marr's colleagues at MIT. He died of leukemia in 1980.
Marr wrote in his introduction to
Vision that "vision is an information processing task," "that our brains must somehow be capable of
representing this information," and that his work was "an inquiry into the nature of the internal representations by which we capture this information and thus make it available as a basis for decisions about our thoughts and actions." (p.3)
He also wrote that "the fundamental point is that in order to understand a device that performs an information processing task, one needs many different kings of explanations," that "each problem has to be addressed from several points of view — as a problem in representing information, as a computation capable of deriving the representation, and as a problem in the architecture of a computer capable of carrying out both things quickly and reliably." (pp.4-5)
Marr's vision was based on the earlier work of many MIT scientists who saw the brain as a logical machine capable of doing computations, starting with
Warren McCulloch and
Walter Pitts's 1943 paper "A Logical Calculus of the Ideas Immanent in Nervous Activity,"
In Marr's "Epilogue" the
Vision book, he wrote an imagined conversation between himself, his colleague Tomaso Poggio, and
Francis Crick. He began with the work of a
Horace Barlow.
CONVERSATION
Can we begin with the levels-of-explanation idea, since you attribute so much importance to it? How is it related to ideas about feature detectors and in particular to Horace Barlow’s first dogma (1972, p. 380), which states, “A description of the activity of a single nerve cell which is transmitted to and influences other nerve cells, and of a nerve cell’s response to such influences from other cells, is a complete enough description for functional understanding of the nervous system ”?
Here, of course, I must disagree with Barlow’s formulation, although I do agree with one of the thoughts behind this dogma, namely, that there is nothing else looking at what the cells are doing — they are the ultimate correlates of perception. However, the dogma fails to take level one analysis — the level of the computational theory — into account.
Vision/i>, p.336
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