mmunication, such is not their
conscious purpose at the outset. They are presumably congenital and
hereditary modes of emotional expression which serve to evoke responsive
behavior in another animal--the reciprocal action being generally in its
primary origin between mate and mate, between parent and offspring, or
between members of the same family group. _And it is this reciprocal
action which constitutes it a factor in social evolution._ Its chief
interest in connection with the subject of behavior lies in the fact
that it shows the instinctive foundations on which intelligent and
eventually rational modes of intercommunication are built up. For
instinctive as the sounds are at the outset, by entering into the
conscious situation and taking their part in the association-complex of
experience, they become factors in the social life as modified and
directed by intelligence. To their original instinctive value as the
outcome of stimuli, and as themselves affording stimuli to responsive
behavior, is added a value for consciousness in so far as they enter
into those guiding situations by which intelligent behavior is
determined. And if they also serve to evoke, in the reciprocating
members of the social group, similar or allied emotional states, there
is thus added a further social bond, inasmuch as there are thus laid the
foundations of sympathy.

"What makes the old sow grunt and the piggies sing and whine?" said a
little girl to a portly, substantial farmer. "I suppose they does it for
company, my dear," was the simple and cautious reply. So far as
appearances went, that farmer looked as guiltless of theories as man
could be. And yet he gave terse expression to what may perhaps be
regarded as the most satisfactory hypothesis as to the primary purpose
of animal sounds. They are a means by which each indicates to others the
fact of his comforting presence; and they still, to a large extent,
retain their primary function. The chirping of grasshoppers, the song of
the cicada, the piping of frogs in the pool, the bleating of lambs at
the hour of dusk, the lowing of contented cattle, the call-notes of the
migrating host of birds--all these, whatever else they may be, are the
reassuring social links of sound, the grateful signs of kindred
presence. Arising thus in close relation to the primitive feelings of
social sympathy, they would naturally be called into play with special
force and suggestiveness at times of strong emotio