DIFFUSION THEORIESTheory in Cultural Diffusion. In terms of
theory development, cultural diffusion is the actual
movement of a given social institution or physical
implement, while stimulus diffusion is the exchange
or movement of the principle upon which an insti-
tution or implement is based. In the cultural diffu-
sion literature, scholars have enumerated assump-
tions, stated principles, and reviewed empirical
work with the objective of identifying propositions
tested repeatedly and not found to be false. In-
deed, beginning with the work of early twentieth
century anthropologists, one can identify at least
five broadly accepted and empirically supported
claims that form the core of what is called cultural
diffusion theory. First, borrowed elements usually
undergo some type of alteration or adaptation in
the new host culture. Second, the act of borrowing
depends on the extent to which the element can be
integrated into the belief system of the new cul-
ture. Third, elements that are incompatible with
the new culture’s prevailing normative structure
or religious belief system are likely to be rejected.
Fourth, acceptance of an element depends upon
its utility for the borrower. Finally, cultures with a
history of past borrowing are more likely to bor-
row in the future. These claims constitute the
‘‘core propositions’’ of culture diffusion theory;
over the years, each has been qualified and elabo-
rated upon, and corollaries have been created
(Stahl 1994).
Currently, diffusion is seen as a mechanism
for culture change that typically accounts for a
large proportion of any particular culture invento-
ry. The deterministic, linear view of diffusion has
been discredited by the empirical record. The
concept of culture diffusion as a means of under-
standing cultural inventories is entrenched in the
field of cultural anthropology. As the twenty-first
century dawns, a principal controversy among
cultural anthropologists centers on the definition
of culture, rather than upon the acceptability of
culture diffusion. Diffusion theory remains promi-
nent in the archaeology literature, particularly as a
means of tracing culture inventories for groups
over time (Posnansky and DeCorse 1986).
Sociologists were initially involved in the use
of cultural diffusion theory as a means of looking
at cultural change (largely in terms of nonmaterial
culture) in the United States. Initially theory drawn
from anthropology was used (Chapin 1928), but
over time the sociological focus became identify-
ing social psychological motivations and mecha-
nisms supporting the diffusion process (Park and
Burgess 1921, p. 20). Recently, sociological work
directly on culture is bifurcated, with one group of
scientists still emphasizing the social psychological
issues in culture meaning (Wuthnow and Witten
1988), and another more concerned with structur-
al (mathematical or statistical) models of culture
processes themselves (Griswold 1987). Neither
group has especially focused on diffusion theory
as a mechanism to track or identify the content-
outcomes of culture change.DIFFUSION OF INNOVATIONSThe diffusion of innovations has historically fo-
cused on the spread of an idea, procedure, or
implement within a single social group or between
multiple groups. For the most part, scholars of this
tradition define diffusion as the process through
which some innovation is communicated within a
social system. Also important is the notion of a
time dimension reflecting the rate of diffusion,
and the importance of the individual adopter (or
non-adopter) reflecting the role of social influence.The study of innovation diffusion began rath-
er narrowly, grew to dominate the field of rural
sociology for a time, contracted in popularity for
many years, and then spawned wide interest across
several disciplines. Innovation diffusion study con-
tains several groups: those who focus on content
or the specific innovation being diffused; those
who emphasize theoretical elaborations of generic
principles of innovation diffusion; and those con-
cerned with creating structural models to track
diffusion. Particularly in the past decade, the lit-
erature has seen much cross-fertilization, although
mathematical modelers tend to appear less often
in the work of other diffusion scholars. Although
the roots of innovation diffusion theory are seen
to be largely in rural sociology, more recently the
field has become distinctly interdisciplinary with
major advancements made especially in the disci-
pline of communication.Historical Development. The definitive histo-
ry of the diffusion of innovations as a paradigm
was published by Thomas Valente and Everett
Rogers (1995). The roots of innovation diffusion