The Mid-Twentieth Century Baby Boom and the Role of Social Influence. An Agent-Based Modelling Approach

Around the middle of the 20th century, most Western countries experienced a surge in birth rates, called the Baby Boom. This boom was unexpected at the time and the underlying mechanisms are still not entirely clear. It was characterized by high levels of inter- and intra-country variability in fertility, as some regions even experienced fertility decline during the Boom. In this paper, we suggest that social influence processes, propelling a shift towards two-child families, might have played an important role in the observed changes in fertility. Interactions in social networks can lead new types of childbearing behaviour to diffuse widely and thereby induce changes in fertility at the macro level. The emergence and diffusion of a two-child norm resulted in homogenization of fertility behaviour across regions. Overall, this led to a reduction of childlessness and thus an increase of fertility, as more people aspired to have at least two children. Yet, in those regions where larger family sizes were still common, the two-child norm contributed to a fertility decline. To explore the role of social influence with analytical rigor, we make use of agent-based computational modelling. We explicate the underlying behavioural assumptions in a formal model and assess their implications by submitting this model to computational simulation experiments. We use Belgium as a case study, since it exhibited large variability in fertility in a relatively small population during the Baby Boom years. We use census data to generate realistic starting conditions and to empirically validate the outcomes that our model generates. Our results show that the proposed mechanism could explain an important part of the variability of fertility trends during the Baby Boom era

Marital Fertility and Educational Assortative Mating Before, During and After the Baby Boom in Belgium

Over the course of the 20th century, the expansion of female participation in education and the gradual re-entrance of women into the labour market changed the dynamics of union formation and fertility. After the Baby Boom period, the association between wealth or social status on the one hand and fertility on the other was turned around. In the meantime, educational attainment became a key determinant of fertility. In this paper we investigate the relation between educational assortative mating and marital fertility. We focus on the fertility trends during the Baby Boom and subsequent Baby Bust, which have been shown to be related to changes in marriage patterns. More particularly, we investigate how changes in the timing and quantum of marital fertility were related to the changing combination of his and her educational attainment. We adopt a couple-oriented approach and use retrospective Belgian census data with rich information on educational attainment and marriage and childbearing histories, which allows us to use event history analysis to analyse fertility of the relevant birth cohorts. Results show that couples where both partners are poorly educated experienced the highest fertility among most of the Baby Boom producing birth cohorts. Hypergamous couples (husband more educated than wife) were not far behind, and their fertility levels even exceeded the levels of the low-educated couples among some birth cohorts. Highly educated homogamous couples had slightly lower fertility than hypergamous couples. Hypogamy (husband less educated than wife) was clearly associated with lower fertility, even among the younger cohorts. The increasing prevalence of hypogamy during the Baby Bust could thus be one factor contributing to the fertility decline.status: publishe

Education and marriage: the shift from female hypergamy to hypogamy in Belgium, a 20th century cohort analysis

One of the key social trends of the 20th century has been the expansion of participation in education. Using detailed retrospective information from the 1981 and 2001 censuses, this paper investigates how this expansion is associated with major trends in nuptiality in Belgium. We focus specifically on the changing gender balance in education and how this is related to the likelihood and timing of marriage and to patterns of educational assortative mating. Our empirical analysis shows that marriage was getting more universal, happening at an earlier age and more often heterogamous in term of education over the cohorts born in the first half of the 20th century. In younger cohorts, when women’s levels of education caught up with men’s, the age at marriage as well as the degree of homogamy increased again. Homogamy remained dominant throughout, but while women tended to marry men who were at least as highly educated as themselves until the 1950s cohorts, in more recent cohorts, women have tended to marry men who are at most as highly educated as themselves. Hypogamy is now the second most common pattern, after homogamy. Controlling for changes in the distribution of educational attainment by applying a log-linear model, we find that part of the changes in assortative mating in Belgium may be explained by changes in mate preferences regarding education. Finally, we find that hypogamous marriages tend to be contracted at later ages than homogamous or hypergamous ones

De recente evolutie van de vruchtbaarheid in het Vlaamse Gewest: 2013-2014

nrpages: 37status: publishe

The Mid-Twentieth Century Baby Boom and the Role of Social Influence. An Agent-Based Modelling Approach

Around the middle of the 20th century, most Western countries experienced a surge in birth rates, called the Baby Boom. This boom was unexpected at the time and the underlying mechanisms are still not entirely clear. It was characterized by high levels of inter- and intra-country variability in fertility, as some regions even experienced fertility decline during the Boom. In this paper, we suggest that social influence processes, propelling a shift towards two-child families, might have played an important role in the observed changes in fertility. Interactions in social networks can lead new types of childbearing behaviour to diffuse widely and thereby induce changes in fertility at the macro level. The emergence and diffusion of a two-child norm resulted in homogenization of fertility behaviour across regions. Overall, this led to a reduction of childlessness and thus an increase of fertility, as more people aspired to have at least two children. Yet, in those regions where larger family sizes were still common, the two-child norm contributed to a fertility decline. To explore the role of social influence with analytical rigor, we make use of agent-based computational modelling. We explicate the underlying behavioural assumptions in a formal model and assess their implications by submitting this model to computational simulation experiments. We use Belgium as a case study, since it exhibited large variability in fertility in a relatively small population during the Baby Boom years. We use census data to generate realistic starting conditions and to empirically validate the outcomes that our model generates. Our results show that the proposed mechanism could explain an important part of the variability of fertility trends during the Baby Boom era.status: publishe

The Mid-Twentieth Century Baby Boom and the Role of Social Influence. An Agent-Based Modelling Approach

Around the middle of the 20th century, most Western countries experienced a surge in birth rates, called the Baby Boom. This boom was unexpected at the time and the underlying mechanisms are still not entirely clear. It was characterized by high levels of inter- and intra-country variability in fertility, as some regions even experienced fertility decline during the Boom. In this paper, we suggest that social influence processes, propelling a shift towards two-child families, might have played an important role in the observed changes in fertility. Interactions in social networks can lead new types of childbearing behaviour to diffuse widely and thereby induce changes in fertility at the macro level. The emergence and diffusion of a two-child norm resulted in homogenization of fertility behaviour across regions. Overall, this led to a reduction of childlessness and thus an increase of fertility, as more people aspired to have at least two children. Yet, in those regions where larger family sizes were still common, the two-child norm contributed to a fertility decline. To explore the role of social influence with analytical rigor, we make use of agent-based computational modelling. We explicate the underlying behavioural assumptions in a formal model and assess their implications by submitting this model to computational simulation experiments. We use Belgium as a case study, since it exhibited large variability in fertility in a relatively small population during the Baby Boom years. We use census data to generate realistic starting conditions and to empirically validate the outcomes that our model generates. Our results show that the proposed mechanism could explain an important part of the variability of fertility trends during the Baby Boom era

Doctoral Efficiency: Summary of the Survey Results & Recommendations

nrpages: 18status: publishe