Biology Reference
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9
Contributions of E. N. Willmer,
P. Saugstad & A. Saugstad,
and I. Lie
The new discoveries of Polyak, Hartline, Kuffler and Granit clearly
indicated that the old orthodox formulation of the duplicity theory
had serious flaws. In particular, the seminal discovery of Polyak and
Granit that rods shared neural pathways with cones appeared to
contradict the basic assumption of the theory that rods and cones
functioned independently of each other. Obviously, the time was ripe
for a reformulation of the theory to make its statements consistent
with the new discoveries. In addition to the reformulations proposed
by Polyak and Granit (see above), important changes to the theory
were made both by Willmer ( 1946 , 1961 ), Saugstad and Saugstad
( 1959 ) and Lie ( 1963 ).
Willmer's reformulation represented a quite new version of
the duplicity theory. Indeed, he held that the rods under photopic
conditions played an important role in trichromatic colour vision.
Saugstad and Saugstad called for a more moderate revision of
the theory. They held that its statements should be reformulated
making the meaning more explicit. Also, they pointed to well-founded
evidence against the theory and concluded that its statements should
be qualified by the development of a more comprehensive theory,
taking into account the structure and function of the nervous
system.
The contributions of Willmer and Saugstad and Saugstad were
primarily theoretical. Lie, on the other hand, made a thorough empirical,
psychophysical investigation focused on rod-cone interactions in colour
vision under mesopic test conditions. In opposition to the orthodox
conception of the duplicity theory, he interpreted his results to mean
that rod and cone activities in the retina antagonized each other over a
long transitional mesopic-intensity interval.
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