A first book in psychology / by Mary Whiton Calkins.

  • Mary Whiton Calkins
Date:
1910
Catalogue details

Licence: Public Domain Mark

Credit: A first book in psychology / by Mary Whiton Calkins. Source: Wellcome Collection.

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    the colorless-light consciousness results not only from mixture of colored lights; it is sometimes excited by a single stimulus. The three most important cases in which one colored light, falling on the retina, is seen as gray are (a) in the faint light or twilight when, as the saying is, “all cats are gray”; (b) in color-blind eyes 10 to which some one color (most often red or green) or even all colors appear as gray; * (c) when the colored light falls on the peripheral or outer edge of the retina. If, for instance, a small colored object be brought toward the field of vision from the right side, while the left eye is closed and the right eye firmly fixated on something directly in front of the face, it will be found that the colored object at first seems gray, and that it is seen in its true color only as it approaches the centre of the eye.f (b) The Physiological Conditions of the Consciousness of Color and Colorless Light Even the attempt to offer a physical explanation of our vis¬ ual sensations has led us, thus, to refer to physiological retinal conditions. We must now undertake a completer enumera¬ tion of these physiological conditions of vision. And it will be convenient to describe together the conditions of the color¬ consciousness and the colorless-light consciousness. In brief, the main physiological conditions of vision are the following: (i) A specific retinal process; (2) an excitation of the optic nerve which connects retina and brain; (3) an ex¬ citation of the visual brain centre — probably the cortex of * For experiments, cf. Sanford, 135. t For experiments, cf. Sanford, 137a; Titchener, §9; C. E. Seashore, “Elementary Experiments in Psychology,” Chapter III. (Footnote ref¬ erences to “Seashore” are to this book.)
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