When it comes to the physical and psychological benefits of being exposed to nature — and especially to scenery that is filled with lush plant life — the evidence lately has been rolling in.
Recently we reported on a study by Australian researchers showing that brief 40 second micro-breaks, in which students looked at computerized images of a green roof, led to improved performance on an attention-demanding cognitive task.
And now, in what appears to be the first study of its kind, a team of researchers find myriad additional benefits for schoolchildren who go to schools that feature lots of green spaces and natural scenery. Kids exposed to more greenery — as measured by satellite imagery of their schools and neighborhoods — showed not only better attention, but also superior working memory.
The research, conducted by researchers from Spain, Norway, and the United States — and led by Payam Dadvand of the Centre for Research in Environmental Epidemiology in Barcelona — studied 2,593 seven- to 10-year-old children from 36 Barcelona schools over the course of a full year. It was published Monday in the Proceedings of the National Academy of Sciences.
The students each took four repeated cognitive tests over three-month intervals in the space of a year. At the same time, for each kid, the researchers used satellite imagery to assess the amount of green space around the home, along the path to and from school, and around the school itself. This did not exclusively mean parks but rather included trees, plants, and grasses.
Children generally show improvement over time in these tests, as their brains develop. But kids with more exposure to greenery improved more, on average, in working memory, higher order “superior working memory,” and attentiveness. Interestingly, however, the greenness of the home (or lack thereof) didn’t seem to matter much — rather, it was the greenness of the commute and especially the school that made the difference.
“The kids where there was more green around the school, we saw better cognitive development, so they did better on these tests,” said Mark Nieuwenhuijsen, a researcher with the Centre for Research in Environmental Epidemiology in Barcelona and one of the study’s authors. “It was about a five percent difference over the time period.” That’s an amount, said Nieuwenhuijsen, that may sound small but “on a population scale, this can have huge effects.”
At the same time, the researchers also assessed levels of what they called traffic-related air pollution, which naturally tends to be lower in areas with more green space. And they found that when the role of pollution was added into their models, this seemed to be a very important factor — it explained 20 to 65 percent of the link between greenery and better cognitive development.
“Our observed beneficial associations between greenness exposure and cognitive development could have been partly mediated by reduction in exposure to [traffic-related air pollution],” the authors wrote. However, based on their data, it appeared unlikely that this factor alone could explain all of the benefit — just a significant part of it.
“We don’t think it’s all air pollution,” said Nieuwenhuijsen. “I think it’s also some kind of direct effect, when you look at green space and mental health, you see quite a beneficial effect of green space on mental health.”
That raises the question of what, precisely, is the mechanism by which exposure to greenery seems to have so many beneficial effects.
The authors list a variety of other possible mechanisms: Less exposure to distracting noise, for instance, or more likelihood of engaging in outdoor exercise.
Environmental Photographer of the Year 2015
Environmental Photographer of the Year 2015
1/15 Fishing net checking, Vietnam 2014 by Hoang Long Ly
Fishermen check their nets in Vietnam. The marine economy is one of the strongest economic sectors of Vietnam; it is targeted to reach 53 to 55 percent of GDP by 2020 and to comprise more than 60 percent of the country’s export turnover
2/15 Glacier 1987, Mount Kenya 2014 by Simon Norfolk
Climate change and the melting of Lewis Glacier, Mount Kenya, from a series entitled ‘When I Am Laid in Earth’. The flame line shows the Lewis Glacier's location in 1987. The glacier has receded about 120m. In 1987 the Curling Pond's surface was 15m higher than presently and the back wall was a tall wall of ice, the glacier's snout. The fire is made from petroleum. The photographer insists that his images contain no evidence that the glacier's retreat is due to man-made warming (glaciers can retreat when the don't get sufficient snow, or if the cloud cover thins, for example,) but it is nonetheless my belief that humans burning hydrocarbons are substantially to blame
3/15 Plastic tree #20, Bolivia 2014 by Eduardo Leal
Plastic bags are part of the landscape in the Bolivian Altiplano. The accumulation of plastic bags on the environment cause deterioration of the landscapes and agriculture soils and it is associated to the death of domestic and wild animals. The world consumes over one million plastic bags every minute
4/15 Collecting crabs, Satkhira 2014 by Kazi Riasat Alve
This man has a huge area of land capable of being farmed productively. A severe cyclonic storm Aila hit the west Bengal coast, west of the Bangladesh border, on 25 May 2009. It caused a storm surge of 2-3m above tide levels along the west Bengal and Bangladesh coasts, with severe devastation to these areas. His land was waterlogged and is no longer cultivable due to the high salinity of soil and water. Now he supports his family by collecting crabs and selling them at the market
5/15 Sandstorm in the city, Kuwait 2011 by Rizalde Cayanan
On Friday 25 March 2011 a severe sandstorm very suddenly enveloped parts of Kuwait. It shut down Kuwait's International Airport and the dust storm reduced visibility to less than 500 metres; in some areas, there was reportedly no visibility at all
6/15 Beauty Salon, Lagos, Nigeria 2014 by Petrut Calinescu
Two women, dressed in purple and holding hair weaves, stand in the doorway of a hair and beauty salon, one of several such waterside establishments in Makoko, Nigeria. They are usually very busy on Sunday, when the women of the local community are preparing for church
7/15 The abandoned village of Geamana, Romania 2014 by Glyn Thomas
The abandoned village of Geamana in the Apuseni Mountains in Romania - a village that was deliberately abandoned and flooded to form a tailings pond for a vast copper mine.400 families were evacuated and the village flooded to create a tailings pond for the toxic waste from the nearby copper mine at Rosia Poieni. The church tower and a few houses are all that remain, engulfed in contaminated sludge
8/15 Retrace our steps, Fukushima 2014 by Carlos Ayesta and Guillaume Bression
Midori Ito is staged in an abandoned supermarket in Namie City inside the Fukushima no go zone. In this area, nothing has changed since the disaster happened. The products stored in the supermarket have passed the date by sell for several years now. Ironically, a sign written in Japanese says « Fresh products ». The photographers asked former residents or inhabitant from the Fukushima region, and in some cases, the actual owners of certain properties, to join them inside the no-go zone and open the doors to these ordinary, but now unfriendly, places. Facing the camera, they were asked to act as normally as possible, as if nothing had happened. The idea behind these almost surreal photographs was to combine the banal and the unusual. The fact of the historical nuclear accident gives these images a real plausibility
9/15 Cladonia Forest, USA 2014 by Matthew Cicanese
The anatomy of forest micro-biomes consists of an intricate web of organisms with highly complex relationships, interactions, and elements. This photographic series illuminates the beauty of various micro-biota that reside on the forest floor. Earths biodiversity is being snuffed out by the exponential growth of the human population. It is the photographer’s goal as an environmental documentary artist to photograph these miniscule lifeforms in a way that voices the splendor and magnificence of their existence, and promotes the conservation of ecosystems and biodiversity
10/15 Life in tidal flood 3, Chittagong, Bangladesh 2014 by Jashim Salam
A family watching TV, waits for water to recede during a tidal flood in Chittagong. In the past few years, tidal surge – sea levels rising significantly - has begun to affect the city, resulting in frequent flooding of residential and business areas. Considering the present warming trends, the report warns that even 20 to 30 years from now shifting rain patterns could leave some areas of the country underwater. If the sea level rises 65cm in 2080, around 40% of arable land will be lost in southern Bangladesh. It notes about 20 million people in the coastal areas are affected by salinity and will be climate refugees. Chittagong is often regarded as the commercial and industrial capital of Bangladesh. If things continue to worsen, most of Chittagong could become completely submerged in the near future and millions will be climate refugees
11/15 Life in the ship breaking yard, Chittagong 2014 by Yousuf Tushar
The ship breaking industry at Sitakunda started its operation in 1960. Due to low labour costs and less stringent environmental regulations Chittagong ship breaking yard boomed in a very short period of time. It has destroyed thousands of trees in the coastal area. It results in constant harmful oily substance leakages from ships, dangerous vapours and fumes from burning materials making this coastal belt a highly polluted area
12/15 Namaj and City, Bangladesh 2015 by Joydeep Mukherjee
On the Day of Bishwa Ijtema, that takes place in Tongi near Dhaka, is the world’s third largest Muslim congregation. People from all over Bangladesh and its neighbourhood gather here to offer Namaj for peace and prosperity
13/15 Solar Portrait, Myanmar 2014 by Ruben Salgado Escudero
Daw Mu Nan, 45, a Padaung farmer and mother of eight, at her grandson's home in Pa Dan Kho Village, Kayah State. This portrait depicts the lives of inhabitants from remote areas of Myanmar who for the first time have access to electricity through the power of solar energy. Each subject was asked how having electricity has affected their life. The portrait was set up within their environment, according to the sitter's wishers. The scenes have all been lit only by solar powered light bulbs which are contributing to the improvement in these peoples standard of living
14/15 Berber 2, Turkey 2011 by Hayri Kodal
A lone barber shop stands in Konya, Turkey, with its electricity supply still working. Konya is best known as a busy university city, and an economic boom town. But this photograph tells a somewhat different story
15/15 The Devil’s gold, Indonesia 2014 by Luca Catalano Gonzaga
Inside the womb of the Ijen Kawah volcano, in Eastern Java, Indonesia, the miners go deep in search of the 'Devil's gold', as sulfur has always been known. lpan, 27, a sulfur miner of ten years, looks for sulfur slabs under the toxic fumes
In addition there is the “biophilia” hypothesis, associated with Harvard evolutionary biologist E.O. Wilson, who postulates that because humans evolved in certain kinds of green landscapes, we in effect have a psychological need for them. Thus, when we are deprived of greenery, it is harmful to our psyches.
In this interpretation, it’s not so much that green spaces help us as that the lack of them harms us. Or as one writer on the subject puts it: “If there is an evolutionary basis for biophilia, as asserted by E.O. Wilson…then contact with nature is a basic human need.”
‘This inborn response to nature can be very instrumental to health, and productivity, and physical and mental well-being,” added Stephen Kellert, a Yale researcher who has collaborated with Wilson in investigating the biophilia hypothesis and is trying to apply it in the built environment, through architectural design.
The implications of the research seem clear — schools should plant lots of trees and gardens and, more generally, cities should foster as much greenery as possible.
“Improved cognitive development in children attending schools with more greenness could result in an advantage in mental capital, which, in turn, would have lasting effects through the life-course,” noted the study authors.
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