ke."[154]

This brief resume of the general literature upon the social process and
social interaction is introductory to an examination of the more
concrete material upon communication, imitation, and suggestion.

2. Communication

"Many works have been written on Expression, but a greater number on
Physiognomy" wrote Charles Darwin in 1872. Physiognomy, or the
interpretation of character through the observation of the features, has
long been relegated by the scientific world to the limbo occupied by
astrology, alchemy, phrenology, and the practice of charlatans.

While positive contributions to an appreciation of human expression were
made before Darwin, as by Sir Charles Bell, Pierre Gratiolet, and Dr.
Piderit, his volume on _The Expression of the Emotions in Man and
Animals_ marked an epoch in the thinking upon the subject. Although his
three principles of utility, antithesis, and direct nervous discharge to
explain the signs of emotions may be open to question, as the
physiological psychologist, Wilhelm Wundt, asserts, the great value of
his contribution is generally conceded. His convincing demonstration of
the universal similarity of emotional expression in the various human
races, a similarity based on a common human inheritance, prepared the
way for further study.

Darwin assumed that the emotion was a mental state which preceded and
caused its expression. According to the findings of later observation,
popularly known as the James-Lange Theory, the emotion is the mental
sign of a behavior change whose external aspects constitute the
so-called "expression." The important point brought out by this new view
of the emotion was an emphasis upon the nature of physiological changes
involved in emotional response. Certain stimuli affect visceral
processes and thereby modify the perception of external objects.

The impetus to research upon this subject given by Darwin was first
manifest in the reports of observation upon the expression of different
emotions. Fear, anger, joy, were made the subjects of individual
monographs. Several brilliant essays, as those by Sully, Dugas, and
Bergson, appeared in one field alone, that of laughter. In the last
decade there has been a distinct tendency toward the experimental study
of the physiological and chemical changes which constitute the inner
aspect of emotional responses, as for example, the report of Cannon upon
his studies in his book _Bodily Changes in Pain, Hunger,