Children raised in greener neighbourhoods have higher IQs and lower levels of difficult behaviour, study finds
Only a small groan about this study. Income is of course the big potential confounder. Rich people tend to be the ones living in leafy areas and they tend to be smarter.
And the rearchers knew that and tried to control for it. And they didn't do a bad job. But both the index of income and the index of greenery encountered were geographical rather than personal so the correlations were ecological and such correlations are often high. The results are not given in correlational form but appear to be undramatic so are lower than expected in the circumstances. Testing the theory using individual measures could well have confirmed the nul hypothesis.
That the finding is not a strong one is also suggested by the fact that it was found in urban areas only, not in suburban or rural areas
Growing up in an area with more green space is beneficial to a child's intelligence, according to a new study that found those in greener urban areas had a higher IQ.
A team from Hasselt University, Belgium, analysed IQs of over 600 children and then used satellite images to examine the green coverage of their neighbourhoods.
The children in the study were all aged between 10 and 15, according to the team, who say a 3 per cent increase in greenery led to an IQ increase of about 2.6 points.
Researchers also found that children in the study had lower levels of behavioural problems if they lived in an area that more green coverage.
IQ point increases as a result of living in a green environment had the biggest impact on those at the lower end of the spectrum as small changes made a big difference.
This is the first time IQ has been considered as a potential benefit of being exposed to green spaces in childhood - other studies have looked at wider cognitive benefits.
The researchers aren't sure exactly why IQ increases with exposure to a green environment, but suspect it could be to do with lower levels of stress.
The data on IQ and location came from the East Flanders Prospective Twin Survey (EFPTS), a registry of multiple births in the province of East Flanders, Belgium.
The average IQ of those involved was 105 but the team found 4 per cent of the children with a score below 80 had grown up in areas with low greenery levels.
It wasn't just intelligence that was impacted by living in an area that was more green - the team found it also helped improve the behaviour of some of the children.
They found that behavioural problems reduced for every 3 per cent rise in greenery.
The team said that a well planned city could offer unique opportunities to create an 'optimal environment' for children to develop to their full potential.
'Whereas in 1950, only 30 per cent of the world’s population lived in urban areas; nowadays, this is already more than half of the global population, and it is expected to increase to 68 per cent by 2050,' the team explained.
'There is more and more evidence that green surroundings are associated with our cognitive function,' study author Tim Nawrot told The Guardian.
'I think city builders should prioritise investment in green spaces because it is really of value to create an optimal environment for children to develop their full potential.'
According to the study authors the benefits of greenery recorded in urban areas weren't replicated in more rural communities - likely because those areas had enough green space for everyone to benefit so the effects weren't as localised.
The authors believe that a combination of lower noise levels and lower stress levels found in green space areas contribute to the improvements in IQ and behaviour.
Part of this is also due to the fact there are more opportunities for physical and social activities in areas with more greenery - which can improve IQ scores on their own.
'Our results indicate that residential green space may be beneficial for intellectual and behavioural development of children living in an urban environment.
'We showed a shift in the IQ distribution of urban children in association with residential green space exposure,' the authors wrote.
The findings have been published in the journal PLOS Medicine.