migration: international 3023


Why international migrations occur is a ques
tion asked by scholars of migration. Several
partial theories have been advanced by social
scientists to explain international migration but
there is no general theory of international
migration. Theories that have been offered to
explain international migration tend to stem
from disciplinary paradigms. Political scientists
focus on the role of the state and the impor
tance of state policies in channeling and limit
ing immigration while economists direct their
attention to economic differentials between
countries, particularly wage gaps and supply
and demand for labor in sending and receiving
countries, and look at how migration and devel
opment interact. Sociologists continue to be
influenced by the Chicago School of Sociology
which developed theories of immigrant incor
poration and assimilation based on the experi
ences of European immigrants to US urban
areas in the early 1900s. While immigrant assim
ilation remains a central study issue for sociolo
gists, a number of sociologists have started to
examine the origins of contemporary interna
tional migration and the global forces driving it.
Under the auspices of the International
Union for the Scientific Study of Popula
tion (IUSSP), Douglas Massey and colleagues
(1993a, b) undertook an evaluation of migration
flows into North America, Western Europe, the
Gulf States, the Asia Pacific region, and South
America and concluded that those flows have
their origins in the social, economic, and poli
tical transformations now occurring in send
ing and receiving countries. The IUSSP group
also advanced the argument that international
migrations are not driven by a lack of develop
ment, as is commonly argued, but by devel
opment itself (Taylor & Massey 2004) and are
likely to grow in the years ahead. In other
research, Massey (1990) offered the theory of
cumulative causation to explain why interna
tional migrations continue after the precipitat
ing economic or political factors that initiated
the migration flow changes. According to
cumulative causation theory, new conditions
that arise in the course of migration come to
function as independent causes themselves:
migrant networks spread, institutions support
ing transnational movement develop, and the
social meaning of work changes in receiving
societies (Massey et al. 1993a).
New theories of international migration have
been advanced by social scientists because ear
lier theories were considered inadequate to
account for the changing direction, volume,
and types of migration that have emerged dur
ing the globalization era of international migra
tion. The earlier theories, including Lees
(1966) pushpull, Stouffers (1940) intervening
opportunities, and Zelinskys (1971) mobility
transition, were judged as too static to explain
the directions of contemporary international
migration or why some people migrate while
most do not. Neoliberal theories advanced by
economists that posited that individuals will
migrate to destinations where they expect to
receive the greatest net benefit were also criti
cized by sociologists for assuming both that
labor market differentials alone determine inter
national migration and that potential migrants
can calculate those risks.
Criticisms have also been directed at the new
theories. For instance, the theories advanced by
the IUSSP group focus on explaining why
labor migrations occur but ignore other types
of migration. Alejandro Portes (1999) argues
that the dimensions that are part of contempor
ary international migration are too disparate to
be explained by a single theory. Portes (1999:
28) argues further that rather than focusing on
a grand theory of international migration,
scholars should direct their attention to four
separate processes, including: the origins of
immigration, the directionality and continuity
of migrant flows, the utilization of immigration
labor in receiving countries, and the integration
and assimilation of immigrants in receiving
Some scholars have begun the process of
advancing theories on parts of the international
migration process. Zolberg et al. (1989) elabo
rated a theory of refugee migrations that held
that those flows have been transformed in
recent decades by globalization forces that
affect the scale of civil and political conflict
within and between nations. Others situate the
new international migrations in the changing
transnational networks and systems of countries