Keeping up with the Joneses may decrease fertility, according to a new study.

A new mathematical model developed by researchers from Emory University revealed that fertility drops as competition for social status goes up.

Paul Hooper, an anthropologist at Emory University, said that the latest findings support real world scenarios in both modern and hunter-gatherer societies.

"The areas were we see the greatest declines in fertility are areas with modern labor markets that have intense competition for jobs and an overwhelming diversity of consumer goods available to signal well-being and social status," said Hooper. "The fact that many countries today have so much social inequality - which makes status competition more intense - may be an important part of the explanation."

"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," Hooper explained.

Hooper and his team note that fertility has gone down globally , and factors like access to birth control, higher education and lower child mortality rates are "insufficient" when it comes to explaining recent statistics.

"While these factors are very important they are insufficient to explain the drops in family sizes that we are seeing," said Hooper

Hooper and his team said the latest findings can also be seen in modern hunter-gatherer societies.

"In a hunter-gatherer society, parents have a limited number of things available to invest in: Food, clothing and shelter," said Hooper. "The average Tsimane family has nine children and they can provide these basic needs for all of them."

However, the size of Tsimane families tends to become smaller the closer they are to Spanish-speaking towns and come into contact with market economies and industrialized products.

"When they start getting earnings for the first time, they spend money 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," Hooper said. "I got the impression that these things were largely symbolic of their social status and competence."

Researchers said that the latest findings are important because they show how prioritizing prestige and social standing can hurt society.

"The human species is highly social and, as a result, we appear to have an ingrained desire for social standing," Hooper concluded. "The problem is that our brains evolved in a radically different environment from that of the modern world. Evolution didn't necessarily train us very well for the almost infinite size of our communities, the anonymity of many of our interactions and the vast numbers of goods that we can use to signal our status. Our evolved psychology may be misfiring and causing us to overinvest in social standing."

The findings are published in the journal Philosophical Transactions of the Royal Society B.