By Lambert Strether of Corrente.
Readers know I often advocate walks (and look up; if down, not at your shoes). Being of a melancholic temperament, I think it’s important to move, no matter the direction; and the best way to move is outdoors. And now “the science” backs me up! From The World Journal of Biological Psychiatry, “Spend time outdoors for your brain – an in-depth longitudinal MRI study,” the Conclusion:
Results indicate remarkable and potentially behaviorally relevant plasticity of cerebral structure within a short time frame driven by the daily time spent outdoors. This is compatible with anecdotal evidence of the health and mood-promoting effects of going for a walk. The study may provide the first evidence for underlying ce]rebral mechanisms of so-called green prescriptions with possible consequences for future interventions in mental disorders.
Here are the “materials” for the study:
[W]e investigated six medication-free, healthy, and currently, urban-living individuals (age 24–32 years, one male, all living in Berlin) on 40–50 measurement points, distributed over 6–8 months with magnetic resonance imaging (MRI). Participants were working at the Max Planck Institute for Human Development, where the data was assessed at the MRI scanner at a time of participants’ convenience and not according to a strict schedule. Most participants were scanned about twice a week, between summer 2013 and early 2014.
The Ethics Committee of Charité University Clinic, Berlin, approved of the study, including the fact that the participants were employee members of the institute. Our rationale for this was 2-fold; firstly, we thought that scientists working with MRI regularly can anticipate best what it is like to be in the scanner that regularly and know the typical data handling in science well enough to be able to consent or dissent to it, and also to sharing the data with other scientists. Secondly, it seemed much more feasible and reasonable to ask individuals who were working around the lab already, to participate, because the life changes caused by participating in this study were much lower for members of our institutes, who are regularly pilot subjects for MRI studies anyways.
Lots of confounders here, I would say; I would also imagine that if we wanted to find out whether six scientists living in Berlin and working at the Max Planck Institute ought to get outdoors more, all we would have to do is ask their mothers. Be that as it may:
Most strikingly, and independently of affect, we observed that more hours spent outdoors was associated with higher grey matter volume in [the dorsolateral prefrontal cortex (DLPFC)]. We then searched for factors potentially associated with spending time outdoors, that may also have a positive effect, or that could constitute a potential mechanism by which time spent outdoors may substantiate in more grey matter volume in DLFPC. It came as a surprise to us that none of these covariates, namely sunshine duration, amount of fluid intake, hours of free time, or physical activity, explained variance in DLPFC volume. A factor that we were not able to enter as a covariate, and that may potentially explain the observed effect, is air pollution. It is well-known that air pollution is oftentimes worse indoors compared to outdoors, when the air is not well-ventilated, which can seriously affect the health of the inhabitants (Leung 2015; WHO 2021). This could potentially explain the positive effects of spending time outdoors on the brain and affect. However, further studies are needed in which the exact time and location of outdoor exposure are assessed so that it can be related to air pollution measurements, ideally combined with devices measuring indoor air quality.
(The study, though published this month, was conducted in summer 2013 and early 2014, making the suggestion that ventilation makes a difference all the more poignant. It is pleasant to think that the effect of properly understanding aerosol transmission could have the knock-on effect of improving people’s positive affect.)
Results indicate remarkable and potentially behaviorally relevant plasticity of cerebral structure within a short time frame driven by the daily time spent outdoors. This is compatible with anecdotal evidence of the health and mood-promoting effects of going for a walk. The study may provide the first evidence for underlying cerebral mechanisms of so-called green prescriptions with possible consequences for future interventions in mental disorders.
I’m not at all sure about “cerebral mechanisms.” For example, if we thought that going for a walk would have a mechanical effect, that would eliminate the element of surprise (like, say, the 100th psychedelic experience as opposed to the first). But would a walk without surprise — as a walk in, for example, a prison might be — have the same “mood promoting effect”? I doubt it. However, I do like “potentially behaviorally relevant plasticity of cerebral structure.” I don’t think the brain (hence, hence doing a lot of work, here, the mind) is easily malleable. However, it’s important to understand that the brain (hence, the mind) is not the seat of an essence, as modern-day phrenologists believe. Finally, for those who believe that consciousness is not seated within the skull, it would seem natural that expanding its field of operation from indoors to outdoors would have a material effect, much as a flooding river cuts deeper into its banks.
The Financial Times seems to have arrived at the same conclusion in the same week, albeit by a different route. From (granted, in the “How to Spend It” section) “‘Gardening is a way to be a human being” (the photographs are gorgeous; clear your cookies, search on the title, and click through):
Spaniard Fernando Caruncho is acclaimed for his vast minimalist landscapes but much prefers to be called a gardener, one who believes his profession is about more than planting and prettifying: it is “a way to be a human being”…. Plato taught his students in the garden of Akademos while Aristotle’s Lyceum was a verdant plot with a shaded grove (from where it got its name) and a botanical garden. These were the places where the physical and spiritual came together. “The garden is the place of knowledge. It is a fundamentally spiritual point of view,” he says.
I don’t much like the word “spiritual,” partly because at least in this culture we oppose it to the material, and partly because of woo woo in the form of scented candles, grifters, and priests (sorry for the redundancy). But replace it with “green prescription” and “positive affect” and I can cope. More:
Caruncho’s objective is to create a transformative space.
That is an excellent objective. Gardening certainly transformed me (as I believe, for the better).
He often uses a minimal palette, referencing the natural colours of the surrounding landscape. Critics have accused him of disliking flowers, which are used sparingly, but he insists that he loves them. “There is nothing more delicate, wonderful, surprising and beautiful than a jasmine, a rose, an orange blossom or a camellia,” he says, revealing that he plants flowers with restraint to underline or enhance an overall scheme. He is known to use mass plantings of a single plant – cosmos or camellias, oleanders, figs, cypress or olive trees – in praise of them.
Masses of color in a “grandmother’s garden“: My ideal, though indeed I do not garden in a Mediterranean climate:
“One flower is all flowers,” he says. “In the Mediterranean [where most of his gardens can be found] the blossom time is very short, mostly from May to June, which is why I use the flower as a counterpoint between the trees and the rocks.”
That’s totally untrue. For one thing, different flowers attract different pollinators.
Every space is a living artwork [like Amazonia] that dies and is reborn, and each is individual, requiring a response that summons up the spirit of the place. It is the living, changing environment that makes each project so unique. The three elements he sees as critical are geometry, water and light, and his starting point, even when designing a small urban garden, is the sky.
That’s a great tip for planning a garden, making the sky the starting point. That forces you to look somewhere other than your shoes or feet; induces you to think about prevailing winds (birds; fungus) and the arc of light across the plot; and gets you thinking about canopy right away (instead of five years on.
Of course, you may not have a plot of earth to garden in, or access to a community garden, or even a balcony to grow plants in pots on (as I know some readers do). I can’t advise house plants, because I don’t know how to keep them alive. But hopefully, you can at least get outside — double-masked in the age of Delta, and keeping an even greater distance than was usual — and look at other people’s gardens, or walk through public gardens. (You could also try dumping packets of wildflower by the road or in the median, just to see what grows.)
However, if you seek to benefit from “potentially behaviorally relevant plasticity of cerebral structure” through gardening, do remember or consider this passage from Ursula LeGuin’s story, “Old Music and the Slave Women,” set in a world where there is a civil war between slaveowners and slaves. Esdan, “Old Music,” a diplomat captured by slaveowners, looks out from the window of his cell and muses:
The room looked out from the second floor over the gardens of Yaramera, terraced slopes and flowerbeds, walks, lawns, and a series of ornamental lakes and pools that descended gradually to the river: a vast pattern of curves and planes, plants and paths, earth and still water, embraced by the broad living curve of the river. All the plots and walks and terraces formed a soft geometry centered very subtly on an enormous tree down at the riverside. It must have been a great tree when the garden was laid out four hundred years ago. It stood above and well back from the bank, but its branches reached far out over the water, and a village could have been built in its shade. The grass of the terraces had dried to soft gold. The river and the lakes and pools were all the misty blue of the summer sky. The flowerbeds and shrubberies were untended, overgrown, but not yet gone wild. The gardens of Yaramera were utterly beautiful in their desolation. Desolate, forlorn, forsaken, all such romantic words befitted them, yet they were also rational and noble, full of peace. They had been built by the labor of slaves. Their dignity and peace were founded on cruelty, misery, pain. Esdan was Hainish, from a very old people, people who had built and destroyed Yaramera a thousand times. His mind contained the beauty and the terrible grief of the place, assured that the existence of one cannot justify the other, the destruction of one cannot destroy the other. He was aware of both, only aware.
Of course, our situation is not Esdan’s. But if you do end up gardening, my advice would be to avoid “the labor of slaves” — in modern terms, “the labor of wage slaves” — insofar as possible. Grow as much as possible from seed. Make sure your seed supplier is either a co-op or very small. Do not patronize box stores (they’re unhealthy anyhow). Let no organic matter leave the property. If possible, don’t bring any in either (I had a very bad experience with landfill mulch, of which more later). Avoid pesticides or insecticides, and make sure they don’t poison the water or the soil if you use them. And so on. Detach yourself as much as you reasonably can from, well, capital. You can’t build a “transformative space” by incorporating materials designed to keep you exactly who and what you are. And where, and how, and why!
 Although a cynic would suggest that’s why aerosol transmission is so vociferously opposed, especially in schools.