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Green space effects

By Steve Draper,   Department of Psychology,   University of Glasgow.

This page is to summarise and hold pointers about the "Green space" phenomenon. I feel we can call it a phenomenon because there are too many reports of carefully observed effects to leave much doubt that there is something substantial here; but no agreement on theory, nor on the scope of the field or area. I list a few student research projects here in this field. I then mention some published papers, selected to illustrate some of the various aspects of the area.

Some projects here on green space

Maxine Swingler,   Niamh Stack   Steve Draper, have all supervised undergraduate research projects in this area. There have been at least two student projects showing that primary school pupils are significantly better at concentrating on school work after a visit to a green space, than after a break of some other kind.

Some lit. refs on green space

Here are (only) a few published papers on the green space phenonmenon, arranged to illustrate a series of distinct ideas, and so to give some idea of the variety of work in the area.

1. Some of the early papers report medical effects. [The first idea about the effects of green space.]
Note that in this first example, it is a view through a window, not being outside in the green space, that is beneficial.

The introduction in the next article, which is from a medical journal, cites numerous reports of medical benefits of green space on: longevity, cardiovascular diseases, people's self-reported general health, mental health, sleep patterns, recovery from illness, social health aspects and birth outcomes. But it stresses that little is known of the mechanisms underlying them.

2. The most often cited "theory" is Attention Restoration Theory (ART). This focusses attention on the idea that the ability to control one's attention is a finite resource that diminishes as it is used, and how green space exposure can replenish attention, and more generally a variety of cognitive abilities. [This is an idea about the cause of green space effects (depletion of a finite mental resource); and also of specific effects (lower cognitive performance of various kinds, until restoration occurs).]

3. On the other hand, an interview in New Scientist with neuroscientist Daniel Levitin has him asserting that what stresses (fatigues) humans is not concentrating attention but switching contexts; and the remedy is day-dreaming not necessarily green space. (I however think that the restorative properties of green spaces often are to do with being able to let your mind drift while walking with nothing too taxing in the way of carrying out the walk. So that this perspective may be important.) [A different idea about the cause of green space effects.]

4. Plant chemicals, and other ecological factors. [Yet wider ideas about the causes of green space effects.]

5. Physical exercise. [An alternative wider idea about the causes of green space effects.]
Opezzo et al (2014) is a notable paper in this area. Firstly, it asks the question of whether the physical exercise usually involved in being in a green space is in fact the main cause of the benefit. Given the enormous amount of evidence for the benefit of exercise to not only physical health, but also mental health, it is important to research this. The study showed that both green space and exercise have a significant benefit, and that although exercise has a greater effect, green space has an additional, independent, one. That is: exercise is important, but not the sole explanation for the effect. From now on, we should scrutinise every study to see whether exercise has been ruled out as an explanation of the results.

The study used "divergent thinking" as its measure, which is a common test of creativity. [This paper thus also offers evidence of a second effect of green space, other than improved attention.]

Furthermore, the study measured the duration of the effect: the improvement in divergent thinking lasted only about two minutes. Most studies fail to measure how long their effect lasts, tacitly assuming that it is durable. It may be that this explains a puzzle in some of the studies of green space effects on school pupils' attention, where teachers were positive that the green space condition results in marked improvements in attention, yet the study failed to show any improvement in tests of learning. It could be that the effect lasts for less than a whole school period (plus time for a test as well).

6. A general effect on well-being as well as on health and on cognitive performance. [This paper thus offers evidence of another, wider effect of green space.]

7. Wider effects on bhicldren.

4. [ccraig] There are increasing claims about the benefits of lots of outdoors
time for children.
5. But perhaps can think about this in relation to flow. Different kinds of
attention.  Novelty yet irresponsibility: thus avoiding both boredom and
[Impact of Green Spaces]
  • Kernan, M. & Devine, D. (2010) "Being confined within? Constructions of the good childhood and outdoor play in early childhood education and care settings in Ireland" Children & Society vol.24 no.5 pp.371-385. doi:10.1111/j.1099-0860.2009.00249.x

    Web documents, mostly with literature references

    Carol Craig's centre (materials written roughly 2018).   Entry by a Jigsaw diagram index   a more textual index

    Particularly these articles:   1   2   Young People

    Time of day effects on school tests that tries to use attention restoration as an explanation

  • Sievertsen,H.H., Gino,F. and Piovesan,M. (2016) "Cognitive fatigue influences students' performance on standardized tests" doi:10.1073/pnas.1516947113

    This discusses a) "cognitive fatigue" in children cf. "attention restoration"; b) A time of day effect on test scores; c) A 20-30 min. rest immediately prior to test also shows an effect.
    We identify one potential source of bias that influences children's performance on standardized tests and that is predictable based on psychological theory: the time at which students take the test. Using test data for all children attending Danish public schools between school years 2009/10 and 2012/13, we find that, for every hour later in the day, test scores decrease by 0.9% of an SD. In addition, a 20- to 30-minute break improves average test scores. Time of day affects students' test performance because, over the course of a regular day, student's mental resources get taxed. Thus, as the day wears on, students become increasingly fatigued and consequently more likely to underperform on a standardized test.

    Note however, that this study has a VERY tiny effect size (but reached significance due to the huge sample size): so not only is this not about a "green" intervention, but it seems too small to bother about.

    Zhao project happiness at UBC

    The survey questions

    Project Happiness
    How are you feeling?
    Welcome! This survey is about your immediate experiences and takes about 5
    minutes to complete. You can participate anytime, anywhere on UBC Vancouver or
    Okanagan campus, and as many times as you want!

    Scales are mostly   0...10   or   -10...0...+10,   with 2 anchor points.

    1. How happy are you feeling at this moment?
    2. How stressed are you feeling at this moment?
    3. How energetic are you feeling at this moment?
    4. How anxious are you feeling at this moment?
    5. How relaxed are you feeling at this moment?
    6. How upset are you feeling at this moment?
    7. How tired are you feeling at this moment?
    8. How confident are you feeling at this moment?
    9. How busy are you at this moment?
    10. How beautiful is your current environment?
    11. How clean is your current environment?
    12. How quiet is your current environment?
    13. How spacious is your current environment?
    14. How hot is your current environment?
    15. How safe is your current environment?
    16. How comfortable is your current environment?
    17. How healthy are you feeling these days?
    18. How long have you been at UBC? (Please specify how many years and months)
    19. How satisfied are you with your life these days?
    20. How much financial stress do you feel on a day-by-day basis?
    21. Are you currently with any friends right now? If so, how many?
    22. What were you doing just before taking the survey?
    23. What is your gender?
    24. Which year were you born?
    25. Please indicate your exact location on the map: ...

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