Declining fertility rates in the West are partially a consequence of heightened competition for social status, according to an anthropological study.
The research suggests that social status has become more important as a consequence of rising social inequality and job competition, and that this has, in turn, caused parents to have fewer children but invest more heavily in their upkeep.
The scientists tested this hypothesis by designing a computational model of how levels of inequality and status competition would affect family size and levels of investment in children. They found that conditions similar to those in 'demographic transition societies' – the developing and developed world – would put a downward pressure on fertility but lead to greater investment in social status and offspring's human capital.
Dr Paul Hooper, an anthropologist at Emory University, and lead author of the paper, said: 'Our model shows that as competition becomes more focused on social climbing, as opposed to just putting food on the table, people invest more in material goods and achieving social status, and that affects how many children they have.'
This chimed with the real-world situation, he added: 'The areas were we see the greatest declines in fertility are areas with modern labour markets that have intense competition for jobs and an overwhelming diversity of consumer goods available to signal well-being and social status.'
The authors say, however, that other factors lie behind declining birth rates in the West, including the provision of contraceptives, lower child mortality rates and the greater entrance of women into higher education.
The study stems from an earlier piece of research conducted by Dr Hooper on the Tsimane tribe, who live in the Amazonian rainforest. Tsimane families had around nine children on average, and their way of life did not require them to invest too heavily in each child. However, Dr Hooper observed that this changed when Tsimane families moved closer to Spanish-speaking towns with market economies.
As the Tsimane began to earn money they spent it, Dr Hooper said, 'on things you wouldn't really expect, like an expensive wristwatch or a nylon backpack for a child attending school, instead of sending them with a traditional woven bag. I got the impression that these things were largely symbolic of their social status and competence'.
In line with the current study, Hooper also noticed that the families became smaller as Tsimane tribes moved away from their traditional way of life.
The research was published in the Philosophical Transactions of the Royal Society B.