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 fert...

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Main Authors: Eli Nomes, André Grow, Jan Van Bavel
Format: Article
Language:English
Published: International Instititute of Social History 2019-04-01
Series:Historical Life Course Studies
Subjects:
Online Access:https://hlcs.nl/article/view/9309
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author Eli Nomes
André Grow
Jan Van Bavel
author_facet Eli Nomes
André Grow
Jan Van Bavel
author_sort Eli Nomes
collection DOAJ
description 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.
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spelling doaj.art-f883a3ed85974a239e4f9ce929151f012022-12-21T23:14:18ZengInternational Instititute of Social HistoryHistorical Life Course Studies2352-63432019-04-018The Mid-Twentieth Century Baby Boom and the Role of Social Influence. An Agent-Based Modelling ApproachEli NomesAndré GrowJan Van BavelAround 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.https://hlcs.nl/article/view/9309Baby BoomNorm diffusionAgent-based modellingSocial networksSocial influenceFertility
spellingShingle Eli Nomes
André Grow
Jan Van Bavel
The Mid-Twentieth Century Baby Boom and the Role of Social Influence. An Agent-Based Modelling Approach
Historical Life Course Studies
Baby Boom
Norm diffusion
Agent-based modelling
Social networks
Social influence
Fertility
title The Mid-Twentieth Century Baby Boom and the Role of Social Influence. An Agent-Based Modelling Approach
title_full The Mid-Twentieth Century Baby Boom and the Role of Social Influence. An Agent-Based Modelling Approach
title_fullStr The Mid-Twentieth Century Baby Boom and the Role of Social Influence. An Agent-Based Modelling Approach
title_full_unstemmed The Mid-Twentieth Century Baby Boom and the Role of Social Influence. An Agent-Based Modelling Approach
title_short The Mid-Twentieth Century Baby Boom and the Role of Social Influence. An Agent-Based Modelling Approach
title_sort mid twentieth century baby boom and the role of social influence an agent based modelling approach
topic Baby Boom
Norm diffusion
Agent-based modelling
Social networks
Social influence
Fertility
url https://hlcs.nl/article/view/9309
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