ABSTRACT
The modernization paradigm explains the principal secular demographic and social changes in the Petorca Valley. In broad outline the stages of population change in the Petorca Valley correspond to the stages of the demographic transition paradigm. In the Petorca Valley mortality decline preceded family limitation which only began on a large scale once infant mortality levels had dropped by some two-thirds. By 1920 Petorcans began to marry in greater proportions and at younger ages than in previous generations. Only in the 1970s with the initiation of a strong birth control program did interclass diffusion become significant for changing the fertility behavior of Petorcans. If attitudes and aspirations provided motivation for the initial spread of family limitation, mortality decline established the essential demographic context for all types of families, those with premarital births as well as those without. Apparently, in European demographic history the relationship between mortality and fertility change has not been systematic.
