Greener cities mean smarter kids, finds study

City kids who grow up with lots of green space in their neighbourhoods will be smarter and better behaved than those surrounded by concrete, according to a study carried out by researchers at Hasselt and Ghent universities. The study is thought to be the first to seek an association between green space and intelligence.

The researchers analysed IQ measurements of more than 600 twins between the ages of eight and 15 in East Flanders. They assessed greenery in the neighbourhoods where they lived.

The study found that having 3.3% more green space in a radius of three kilometres around the home was associated with an increase of 2.6 points in total IQ.

This is not a very large difference for an individual, but could be significant at the population level. For instance, in an urban environment with less greenery there may be more children at the lower limit of a normal IQ curve.

The finding was not connected to the socio-economic status of the families involved. “The link between green space and intelligence was found in children of parents with both a high and a low level of education,” said Esmée Bijnens, the lead researcher in the study.

More green space was also associated with a reduction in behavioural problems in children, such as aggression or a lack of concentration. However, neither the IQ nor the behavioural benefits of green space could be detected in rural or suburban environments.

Why urban green space has this effect on intelligence is still an open question. It might be because it provides environmental benefits, such as reducing exposure to air pollution, noise and heat. Green space may also encourage health-promoting activities and social cohesion, or help people restore their physical and mental capacities more generally.

Whatever the reason, the effect is worth having. “The study shows that green elements, such as the proximity of a park in a city, can make a difference to children’s development,” said Tim Nawrot, professor of environmental epidemiology at Hasselt University.

Policymakers and city planners should both take note, he said, and work to create “optimal environments where children are given the opportunity to develop their full potential”.

Photo, from top: ©Eric Lalmand/BELGA, ©Thiery Roge/BELGA