I
Man is predominantly a visual animal. To him seeing is believing,--a
saying which in canine parlance might readily become smelling is
believing. We teach by illustrations, models, and object-lessons,
and reduce complex relations to the curves of the graphic method,
to bring home and impress our statements. Our every-day language,
as well as the imagery of poetry, abounds in metaphors and similes
appealing to images which the eye has taught us to appreciate.
The eye is also the medium of impressions of æsthetic as well as
of intellectual value; and one grand division of art is lost to
those who cannot see. The eye, too, forms the centre of emotional
expression, and reveals to our fellow-men the subtile variations in
mood and passion, as it is to the physician a delicate index of our
well-being. There are reasons for believing that it was the function
of sight as a distance-sense that led to its supremacy in the lives
of our primitive ancestors. Whatever its origin, the growth of
civilization has served to develop this eye-mindedness of the race,
and to increase and diversify the modes of its cultivation.
The eye, thus constantly stimulated in waking life, and attracting to
its sensations the focus of attention, possessing, as it does, in the
retinal fovea a special and unique aid to concentrative attention,
does not yield up its supremacy in the world of dreams. The visual
centres subside but slowly from their day's stimulation; and the rich
stock of images which these centres have stored up is completely at
the service of the fancy that guides our dreams. Indeed, the dream
itself is spoken of as a vision.
Though, as a race, we are eye-minded, individually we differ much
with regard to the rôle that sight plays in our psychic life. In
one direction a good index of its importance is to be found in the
perfection of the visualizing faculty, of which Mr. Galton has given
an interesting account. He asked various persons to describe, amongst
other things, the vividness of their mental picture when calling to
mind the morning's breakfast-table. To some the mental scene was
as clear and as natural as reality, lacking none of the details of
form or color; to others the resulting mental image was tolerably
distinct, with the conspicuous features well brought out, but the
rest dim and ill-defined; while a third group could only piece
together a very vague, fragmentary, and unreliable series of images,
with no distinct or constant picture.
Similar differences are observable with regard to memories. Some
persons firmly retain what they read, while the memory forte of
others is in what they hear; and pathology supports this subdivision
of the sense-memories by showing, for example, that all remembrance
for seen objects may be lost while that for sounds remains intact. A
case, remarkable in several aspects, is recorded by M. Charcot. The
subject in question could accurately call up, in full detail, all
the scenes of his many travels, could repeat pages of his favorite
authors from the mental picture of the printed page, and by the same
means could mentally add long columns of numbers. The mere mention of
a scene in a play, or of a conversation with a friend, immediately
brought up a vivid picture of the entire circumstance. Through
nervous prostration he lost this visual memory. An attempt to sketch
a familiar scene now resulted in a childish scrawl; he remembered
little of his correspondence, forgot the appearance of his wife and
friends, and even failed to recognize his own image in a mirror. Yet
his eyesight was intact and his intellect unimpaired. In order to
remember things he had now to have them read aloud to him, and thus
bring into play his undisturbed auditory centre--to him an almost new
experience.
The function of vision in dreams is doubtless subject to similar
individual variations, though probably to a less extent. Seeing,
with rare exceptions, constitutes the typical operation in dreams;
it is this sense, too, that, under the influence of drugs or of
other excitement, is most readily stimulated into morbid action, and
most easily furnishes the basis of delusions and hallucinations to a
disordered mind. The dependence of the nature and content of dreams
upon the waking experiences is so clearly proven that it would be
surprising not to find in them the individual characteristics of our
mental processes; and if Aristotle is right in saying that in waking
life we all have a world in common but in dreams each has a world of
his own, we may look to the evidence of dream-life for indications of
unrestrained and distinctive psychological traits.