You are here

Wealthy families obey economics rather than evolution

Monday, 3. September 2012 - 12:36

"Go forth and multiply" might be poor advice for parents who want to ensure their descendants' economic success. A study in Sweden spanning five generations confirms that the wealthiest families tend to remain small, despite evolutionary pressures to have as many offspring as possible.

Evolutionary biologists are aware of a curious phenomenon that kicks in when societies become industrialised: the wealthiest families begin to have fewer children, suggesting they are no longer concerned with maximising their reproduction.

One likely explanation for this is that having fewer children allows parents to invest more in each child, and divide their wealth fewer ways. Consequently, the children can maintain the high socioeconomic status enjoyed by their parents. In essence, these wealthy families sacrifice numbers to maintain their status.

Wealthy Edwardian family (Photo Loveday Lemon)

Anna Goodman of the London School of Hygiene and Tropical Medicine and colleagues, have now found some evidence in Swedish family records that supports this idea. The team studied the data gathered on 14,000 people born between 1915 and 1929. The records include details of their children, grandchildren and great-grandchildren.

As expected, wealthy parents had fewer children, and those children tended to maintain the high socioeconomic status of their parents. But the study confirmed that this phenomenon continued down the family line: even after four generations, families that had been wealthy in 1915 were still producing fewer children.

Evolutionarily, the model might only apply in safe countries like Sweden, which has one of the longest life expectancies in the world, says James Boone of the University of New Mexico in Albuquerque. "Wage-labour economies underwritten by fossil fuel technology are a lot more 'disaster proof' than pre-industrial forager and agricultural economies."

Monique Borgerhoff Mulder at the University of California, Davis, agrees. In unstable societies, she says, wealthy families risk disappearing if they are not able to buy their way out of social turmoil. In that situation, having a larger family might be more advantageous.

By Sara Reardon

Source: 
www.newscientist.com
Tags: 
Economics
evolution
reproduction
Wealthy families