CHRISTINE LADD-FRANKLIN
Born on December 1, Christine Ladd (1847–1930)
graduated from the then new Vassar College in
1869. She pursued her interest in mathematics at
the also new Johns Hopkins University and, although
she completed all the requirements for
a doctorate in 1882, the degree was not granted
because she was a woman. She was, however, given
an honorary degree by Vassar in 1887. When the
social climate became less discriminating against
women, she was granted her doctorate from Johns
Hopkins in 1926, 44 years after she had completed
her graduate work (she was nearly 80 years old at
the time).
In 1882 Vassar married Fabian Franklin, a
mathematics professor at Johns Hopkins. During
her husband’s sabbatical leave in Germany,
Christine Ladd-Franklin was able to pursue an
interest in psychology she had developed earlier
(she had published a paper on vision in 1887).
Although, at the time, women were generally excluded
from German universities, she managed to
be accepted for a year (1891–1892) in Georg E.
Müller’s laboratory at Göttingen, where Hering’s
theory of color vision was supported. After her
year under Müller’s influence, she studied with
Helmholtz at the University of Berlin, where she
learned about his trichromatic theory of color
vision.
Before leaving Europe, Ladd-Franklin was
ready to announce her own theory of color vision,
which she believed improved upon those of
Helmholtz and Hering. She presented her theory
at the International Congress of Experimental
Psychology in London in 1892. Upon returning
to the United States, Ladd-Franklin lectured on
logic and psychology at Johns Hopkins until she
and her husband moved to New York, where she
lectured and promoted her theory of color vision at
Columbia University from 1910 until her death in
1930.
Ladd-Franklin’s theory of color vision was
based on evolutionary theory. She noted that
some animals are color blind and assumed that achromatic
vision appeared first in evolution and color
vision came later. She assumed further that the human
eye carries vestiges of its earlier evolutionary
development. She observed that the most highly
evolved part of the eye is the fovea, where, at least
in daylight, visual acuity and color sensitivity are
greatest. Moving from the fovea to the periphery
of the retina, acuity is reduced and the ability to
distinguish colors is lost. However, in the periphery
Ewald Hering
Reprinted by permission of Open Court Publishing Company, a division of
Carcus Publishing Company, from Philosophical Portrait Series, © 1898 by
Open Court Publishing Company.
EARLY DEVELOPMENTS IN PHYSIOLOGY AND THE RISE OF EXPERIMENTAL PSYCHOLOGY 243
of the retina, night vision and movement perception
are better than in the fovea. Ladd-Franklin
assumed that peripheral vision (provided by the
rods of the retina) was more primitive than foveal
vision (provided by the cones of the retina) because
night vision and movement detection are crucial for
survival. But if color vision evolved later than achromatic
vision, was it not possible that color vision
itself evolved in progressive stages?
After carefully studying the established color
zones on the retina and the facts of color blindness,
Ladd-Franklin concluded that color vision evolved
in three stages. Achromatic vision came first, then
blue-yellow sensitivity, and finally red-green sensitivity.
The assumption that the last to evolve would
be the most fragile explains the prevalence of redgreen
color blindness. Blue-yellow color blindness
is less frequent because it evolved earlier and is less
likely to be defective. Achromatic vision is the oldest
and therefore the most difficult to disrupt.
Ladd-Franklin, of course, was aware of
Helmholtz’s and Hering’s theories, and, although
she preferred Hering’s theory, her theory was not
offered in opposition to either. Rather, she attempted
to explain in evolutionary terms the origins
of the anatomy of the eye and its visual
abilities.
After initial popularity, Ladd-Franklin’s theory
fell into neglect, perhaps because she did not have
adequate research facilities available to her. Some
believe, however, that her analysis of color vision
still has validity (see, for example, Hurvich, 1971).
For interesting biographical sketches of LaddFranklin,
see Furumoto (1992) and Scarborough
and Furumoto (1987).