The question arises: What is the basis of the influence of the
social heredity, of the forces, in the character of the person
born in a social group? Certain aspects of this we must deal with
later, in order to keep to a unified presentation of the subject.
Other aspects are pertinently to be discussed now.

The link that binds man to man is called the social instinct,
though perhaps it would be better to call it the group of social
instincts. The link is one of feeling, primarily, though it has
associated with it, in an indissoluble way, purpose and action.
The existence of the social instinct is undisputed; its
explanation is varied and ranges from the mystical to the
evolutionary. For the mystical (which crops out in Bergson,
Butler and even in Galton), the unity of life is its basis, and
there is a sort of recognition of parts formerly united but now
separate individuals. This does not explain hate, racial and
individual. The evolutionary aspect has received its best
handling in recent years in Trotter's "The Herd," where the
social instincts are traced in their relation to human history.
One writer after another has placed as basic in social instinct,
sympathy, imitation, suggestibility and the recognition of
"likeness." These are merely names for a spreading of emotion
from one member of a group to another, for a something that makes
members of the group teachable and makes them wish to teach; that
is back of the wish to conform and help and has two sets of
guiding forces, reward and its derivative praise; punishment and
its derivative blame. Perhaps the term "derivative" is not
correct, and perhaps praise and blame are primary and reward and
punishment secondary.