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CHRISTINE LADD-FRANKLINBorn on December 1, Christine Ladd (1847–1930)graduated from the then new Vassar College in1869. She pursued her interest in mathematics atthe also new Johns Hopkins University and, althoughshe completed all the requirements fora doctorate in 1882, the degree was not grantedbecause she was a woman. She was, however, givenan honorary degree by Vassar in 1887. When thesocial climate became less discriminating againstwomen, she was granted her doctorate from JohnsHopkins in 1926, 44 years after she had completedher graduate work (she was nearly 80 years old atthe time).In 1882 Vassar married Fabian Franklin, amathematics professor at Johns Hopkins. Duringher husband’s sabbatical leave in Germany,Christine Ladd-Franklin was able to pursue aninterest in psychology she had developed earlier(she had published a paper on vision in 1887).Although, at the time, women were generally excludedfrom German universities, she managed tobe accepted for a year (1891–1892) in Georg E.Müller’s laboratory at Göttingen, where Hering’stheory of color vision was supported. After heryear under Müller’s influence, she studied withHelmholtz at the University of Berlin, where shelearned about his trichromatic theory of colorvision.Before leaving Europe, Ladd-Franklin wasready to announce her own theory of color vision,which she believed improved upon those ofHelmholtz and Hering. She presented her theoryat the International Congress of ExperimentalPsychology in London in 1892. Upon returningto the United States, Ladd-Franklin lectured onlogic and psychology at Johns Hopkins until sheand her husband moved to New York, where shelectured and promoted her theory of color vision atColumbia University from 1910 until her death in1930.Ladd-Franklin’s theory of color vision wasbased on evolutionary theory. She noted thatsome animals are color blind and assumed that achromaticvision appeared first in evolution and colorvision came later. She assumed further that the humaneye carries vestiges of its earlier evolutionarydevelopment. She observed that the most highlyevolved part of the eye is the fovea, where, at leastin daylight, visual acuity and color sensitivity aregreatest. Moving from the fovea to the peripheryof the retina, acuity is reduced and the ability todistinguish colors is lost. However, in the peripheryEwald HeringReprinted by permission of Open Court Publishing Company, a division ofCarcus Publishing Company, from Philosophical Portrait Series, © 1898 byOpen Court Publishing Company.EARLY DEVELOPMENTS IN PHYSIOLOGY AND THE RISE OF EXPERIMENTAL PSYCHOLOGY 243of the retina, night vision and movement perceptionare better than in the fovea. Ladd-Franklinassumed that peripheral vision (provided by therods of the retina) was more primitive than fovealvision (provided by the cones of the retina) becausenight vision and movement detection are crucial forsurvival. But if color vision evolved later than achromaticvision, was it not possible that color visionitself evolved in progressive stages?After carefully studying the established colorzones on the retina and the facts of color blindness,Ladd-Franklin concluded that color vision evolvedin three stages. Achromatic vision came first, thenblue-yellow sensitivity, and finally red-green sensitivity.The assumption that the last to evolve wouldbe the most fragile explains the prevalence of redgreencolor blindness. Blue-yellow color blindnessis less frequent because it evolved earlier and is lesslikely to be defective. Achromatic vision is the oldestand therefore the most difficult to disrupt.Ladd-Franklin, of course, was aware ofHelmholtz’s and Hering’s theories, and, althoughshe preferred Hering’s theory, her theory was notoffered in opposition to either. Rather, she attemptedto explain in evolutionary terms the originsof the anatomy of the eye and its visualabilities.After initial popularity, Ladd-Franklin’s theoryfell into neglect, perhaps because she did not haveadequate research facilities available to her. Somebelieve, however, that her analysis of color visionstill has validity (see, for example, Hurvich, 1971).For interesting biographical sketches of LaddFranklin,see Furumoto (1992) and Scarboroughand Furumoto (1987).
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