The Dancing Mouse | Page 2

of methods by which
the behavior and intelligence of animals may be studied. As it happens
the dancer is an ideal subject for the experimental study of many of the
problems of animal behavior. It is small, easily cared for, readily tamed,
harmless, incessantly active, and it lends itself satisfactorily to a large
number of experimental situations. For laboratory courses in
Comparative Psychology or Comparative Physiology it well might hold
the place which the frog now holds in courses in Comparative
Anatomy.
Gratefully, and with this expression of my thanks, I acknowledge my
indebtedness to Professor Hugo Münsterberg for placing at my
command the resources of the Harvard Psychological Laboratory and
for advice and encouragement throughout my investigation; to
Professor Edwin B. Holt for valuable assistance in more ways than I
can mention; to Professor Wallace C. Sabine for generous aid in
connection with the experiments on hearing; to Professor Theobald
Smith for the examination of pathological dancers; to Miss Mary C.
Dickerson for the photographs of dancing mice which are reproduced
in the frontispiece; to Mr. Frank Ashmore for additional photographs
which I have been unable to use in this volume; to Mr. C. H. Toll for
the drawings for Figures 14 and 20; to Doctors H. W. Rand and C. S.
Berry for valuable suggestions on the basis of a critical reading of the
proof sheets; and to my wife, Ada Watterson Yerkes, for constant aid
throughout the experimental work and in the preparation of this
volume.
R. M. Y.

CAMBRIDGE, MASSACHUSETTS,
August, 1907.

CONTENTS
LIST OF ILLUSTRATIONS
LITERATURE ON THE DANCING MOUSE
CHAPTER I
CHARACTERISTICS, ORIGIN, AND HISTORY
Peculiarities of the dancing mouse--Markings and method of keeping
record of individuals--The dancer in China and Japan (Kishi, Mitsukuri,
Hatai)-- Theories concerning the origin of the race: selectional breeding;
the inheritance of an acquired character; mutation, inheritance, and
selectional breeding; pathological changes; natural selection--Instances
of the occurrence of dancers among other kinds of mice--Results of
crossing dancer with other kinds of mice.
CHAPTER II
FEEDING, BREEDING, AND DEVELOPMENT OF THE YOUNG
Methods of keeping and caring for dancers--Cages, nest-boxes, and
materials for nest--Cleansing cages--Food supply and
feeding--Importance of cleanliness, warmth, and pure food--Relations
of males and females, fighting--The young, number in a litter--Care of
young--Course of development--Comparison of young of dancer with
young of common mouse-- Diary account of the course of development
of a typical litter of dancers.
CHAPTER III

BEHAVIOR: DANCE MOVEMENTS
Dancing--Restlessness and excitability--Significance of restlessness--
Forms of dance: whirling, circling, and figure-eights--Direction of
whirling and circling: right whirlers, left whirlers, and mixed whirlers--
Sex differences in dancing--Time and periodicity of dancing--Influence
of light on activity--Necessity for prolonged observation of behavior.
CHAPTER IV
BEHAVIOR: EQUILIBRATION AND DIZZINESS
Muscular coordination--Statements of Cyon and Zoth concerning
behavior-- Control of movements, orientation, equilibration, movement
on inclined surfaces, climbing--The tracks of the dancer--Absence of
visual dizziness--Comparison of the behavior of the dancer with that of
the common mouse when they are rotated in a cyclostat--Behavior of
blinded dancers (Cyon, Alexander and Kreidl, Kishi)--Cyon's two types
of dancer-- Phenomena of behavior for which structural bases are
sought: dance movements; lack of response to sounds; deficiency in
equilibrational ability; lack of visual and rotational dizziness.
CHAPTER V
STRUCTURAL PECULIARITIES AND BEHAVIOR
The functions of the ear--Structure of the ear of the dancer as described
by Rawitz, by Panse, by Baginsky, by Alexander and Kreidl, and by
Kishi-- Cyon's theory of the relation of the semicircular canals to space
perception--Condition of the auditory organs--Condition of the
equilibrational organs--Condition of the sound-transmitting
organs--The bearing of the results of anatomical investigations upon
the facts of behavior.
CHAPTER VI
THE SENSE OF HEARING

Experiments on hearing in the dancer made by Rawitz, by Panse, by
Cyon, by Alexander and Kreidl, by Zoth, and by Kishi--Hearing and
the voice-- Methods of testing sensitiveness to sounds--Results of tests
with adults-- Importance of indirect method of
experimentation--Results of tests with young--The period of auditory
sensitiveness--Individual differences.
CHAPTER VII
THE SENSE OF SIGHT: BRIGHTNESS VISION
What is known concerning sight in the dancer--Brightness vision and
color vision--Methods of testing brightness vision, the visual
discrimination apparatus--Motives for discrimination and
choice--Punishment versus reward as an incentive in animal
experiments--Hunger as an incentive--An electric stimulus as an
incentive--Conditions for brightness vision tests-- White-black
vision--Evidence of preference--Check experiments--Conclusion.
CHAPTER VIII
THE SENSE OF SIGHT: BRIGHTNESS VISION (_Continued_)
The delicacy of brightness discrimination--Methods of testing the
dancer's ability to detect slight differences in brightness--Results of
tests with gray papers--Relation of intensity of visual stimuli to the
threshold of discrimination--Weber's law apparatus and method of
experimentation-- Results of Weber's law tests--Practice effects, the
training of vision-- Description of the behavior of the dancer in the
discrimination box experiments--Modes of choice: by affirmation; by
negation; by comparison-- Evidence of indiscriminable visual
conditions.
CHAPTER IX
THE SENSE OF SIGHT: COLOR