THE ROLE OF SIGHT IN THE DAILY LIFE OF THE DANCER
Darting hither and thither in its cage, whirling rapidly,
now to the left, now to the right, running in circles,
passing through holes in the nest box quickly and
neatly, the dancer, it would seem, must have excellent
sight. But careful observation of its behavior
modifies this inference. For it appears that
a pair of mice dancing together, or near one another,
sometimes collide, and that it is only those holes
with which the animal is familiar that are entered
skillfully. In fact, the longer one observes
the behavior of the dancer under natural conditions,
the more he comes to believe in the importance of
touch, and motor tendencies. Sight, which at
first appears to be the chief guiding sense, comes
to take a secondary place. In this chapter it
is my purpose to show by means of simple experiments
what part sight plays in the dancer’s life of
habit formation.
The evidence on this subject has been obtained from
four sources: (1) observation of the behavior
of dancers in their cages; (2) observation of their
behavior when blinded; (3) observation of their behavior
in a great variety of discrimination experiments,
many of which have already been described; and (4)
observation of their behavior in labyrinth experiments
which were especially planned to exhibit the importance
of the several kinds of vision which the dancer might
be supposed to possess. The evidence from the
first three of these sources may be presented summarily,
for much of it has already appeared in earlier chapters.
That from the fourth source will constitute the bulk
of the material of this chapter.
My observation of the behavior of the mice has furnished
conclusive evidence of their ability to see moving
objects. But that they do not see very distinctly,
and that they do not have accurate perception of the
form of objects, are conclusions which are supported
by observations that I have made under both natural
and experimental conditions. In Chapters VII,
VIII, IX, and X, I have presented an abundance of evidence
of brightness vision and, in addition, indications
of a specific sensitiveness to wave length which may
be said to correspond to our color vision. It
is noteworthy, however, that all of the experimental
proofs of visual ability were obtained as the result
of long periods of training. Seldom, indeed,
in my experience with them, have the dancers under
natural conditions exhibited forms of activity which
were unquestionably guided by vision.
It is claimed by those who have experimented with
blinded dancers that the loss of sight decreases the
amount and rapidity of movement, and the ability of
the animals to avoid obstacles.
