Selectivity, Adaptation, or Disruption? A Comparison of Alternative Hypotheses on the Effects of Migration on Fertility: The Case of Brazil

This study, based on Brazilian data from 1976, compared the fertility of migrants and stayers at both origin and destination areas. Observed patterns of fertility differentials were then analyzed in terms of 4 hypotheses of fertility behavior focused on processes of socialization, adaptation, selectivity, and disruption. In the study sample, 31% of migrants moved from rural to urban areas, 45% of moves were between urban areas, and 20% of moves were between rural areas. Among rural-to-urban migrants, only 1/3 moved from traditional to modern regions. To uncover the main patterns of migrant and stayer fertility differentials in the study population, the major flows of migrants by origin and destination were disaggregated by recency of migration, education, and age. The overall conclusions were as follows: 1) rural-urban migration flows need to be disaggregated into various modern/traditional cross-classifications (e.g., modern-rural, traditional-urban, frontier-urban) and greater emphasis needs to be placed on rural-urban, urban-urban, and rural-rural flows; 2) no robust quantitative measures of migrant-stayer fertility differentials held across migrant groups, implying that migrants differing in terms of age, education, origin, and destination are likely to behave in significantly variable fashion with regard to stayer standards of fertility behavior; 3) migrant groups with overall lower fertility levels, such as the young and better educated, are less likely to experience significant fertility reduction to bridge the origin/destination fertility gap; 4) rural-to-rural migrants do not appear to experience any lasting fertility reduction even when they move to areas with lower overall fertility rates; 5) urban-to-rural migrants tend to bridge a larger fraction of the uphill fertility gap than rural-to-urban migrants; urban-to-rural migrants tend to bridge a larger fraction of the uphill fertility gap than rural-to-urban migrants; there was evidence of partial adaptation for most migrant categories once disruption effects disappear and evidence consistent with the socialization hypothesis (no fertility reduction for at least 1 generation) was apparent for migrants originating in the least developed parts of Brazil, the frontier region, and the traditional-rural region.