in is in
accordance with other anthropological and ethnological data in regard to
these peoples, which prove the fact, now well established, that they are
not of African origin.

Similarly Boas' study of the Raven cycle of American Indian mythology
indicated that these stories originated in the northern part of British
Columbia and traveled southward along the coast. One of the evidences
of the direction of this progress is the gradual diminution of
complexity in the stories as they traveled into regions farther removed
from the point of origin.

All this, in so far as it seeks to determine the point of origin,
direction, speed, and character of changes that take place in cultural
materials in the process of diffusion, is clearly history and ethnology.

Other questions, however, force themselves inevitably upon the attention
of the inquiring student. Why is it that certain cultural materials are
more widely and more rapidly diffused than others? Under what conditions
does this diffusion take place and why does it take place at all?
Finally, what is the ultimate source of customs, beliefs, languages,
religious practices, and all the varied technical devices which compose
the cultures of different peoples? What are the circumstances and what
are the processes by which cultural traits are independently created?
Under what conditions do cultural fusions take place and what is the
nature of this process?

These are all fundamentally problems of human nature, and as human
nature itself is now regarded as a product of social intercourse, they
are problems of sociology.

The cultural processes by which languages, myth, and religion have come
into existence among primitive peoples have given rise in Germany to a
special science. Folk-psychology (_Voelkerpsychologie_) had its origin in
an attempt to answer in psychological terms the problems to which a
comparative study of cultural materials has given rise.

From two different directions ideas of folk-psychology have
found their way into modern science. First of all there was a
demand from the different social sciences
[_Geisteswissenschaften_] for a psychological explanation of
the phenomena of social life and history, so far as they were
products of social [_geistiger_] interaction. In the second
place, psychology itself required, in order to escape the
uncertainties and ambiguities of pure introspection, a body of
objective