The Garden and the Brain

August 5, 2009

in Articles, General Interest

by Jenny Woods

In the 21st Century we stand on the brink of a new science of mind.

That’s one hell of a statement – what on earth is it doing on a garden website?

Through advances in cell culture and by imaging the activity in living brains it is possible to examine how the squishy network of neurons in our heads perceives, analyses and stores information about the world around it. I’m a scientist – I need to know the ‘WHY?’ of things and, triggered by Anne’s (Anne Wareham) resonant concept of communicating ‘ideas and deep meaning’ through gardens, I wanted to understand whether discoveries from this field of experimental neurobiology could be relevant to the discussion.

In particular I wanted to explore why the phrase ‘ideas and deep meaning’ seemed to embody two very different levels of human experience – why the idea of the contrast between the Temples of Ancient and Modern Virtue may be intellectually amusing, but a standing stone in a misty hollow seems to communicate meaning at a level of consciousness below verbal reasoning.  In what follows the science is well-founded, the speculation all my own.

From our early years we are taught to categorise our experience of the world in terms of the five senses, but the activity of our brains is much more subtle than this crude segmentation. The forces of evolution have driven our brains to become highly-efficient information-processing machines, rapidly synthesising sensory inputs into world pictures. For me one of the most amazing recent discoveries are cells within the hippocampus (the part of the brain that stores explicit memory) that record place – a set of neurons fires when an animal is in a particular location, these cells form a cognitive map of the environment. In a different location, a different map fires. Imagine that! We struggle to define what we mean when we say a garden captures a ‘sense of place’ yet this sense is recorded at a fundamental level of granularity within our brains – indeed perhaps it is because place is such a basic unit, processed at a subconscious level, that we fumble to interpret it in terms of ‘higher’ concepts.

Another hugely significant discovery is the measuring of conscious and unconscious pathways in the brain. I’m not wanting to get tangled-up in Freudian ego and id here, those are interpretive models that pre-date the ability to measure brain process. We’re talking about physically-measurable signal pathways from the sense-organs to different parts of the brain and from the brain to the muscles and other organs. For example, suppose you hear a loud noise or feel a painful electrical shock. These signals are registered in the thalamus, a major relay-point in the brain. From here two impulses are triggered: one passes directly to the amygdala (the region of the brain associated with emotional states and which co-ordinates hormonal responses and autonomic signals to muscles), the other passes through the part of the cerebral cortex that processes information and then on to the amygdala.

Put more simply, our hormones and muscles are already being told to act before we ‘know’ what set them into action. It’s not just noise and touch that work this way, visual stimuli do too. In fact it’s possible to display frightening pictures to a person so quickly that they are unable to process what the picture is of, yet their amygdala has already become active, sending signals to their body to respond to the threat. It’s not difficult to imagine the evolutionary pressures that drove this – running away from danger has always been a good idea! It is this reaction that Amanda Patton is trying to manipulate when she is designing her ‘feel-bad’ gardens she discusses in her article.

Inputs in the form of written words are neutral, we process them in our higher brain before ‘understanding’ occurs. The word ‘fear’ is merely a set of black and white strokes on a page, it needs processing at a high level, associating with previously-held emotional states, before we react with a frisson of adrenaline and a shiver down the spine. Indeed, if you have never learned to read English, ‘fear’ may never become anything other than a pattern. Complex symbols, words and mathematical notation must be processed in the cerebral cortex before we ‘understand’ what they mean, whereas a simple symbol triggers a nervous pathway that sets our muscles and hormones into action before the higher brain has had time to act. A glimpse of a gaping monster at Bomarzo may cause one to leap away before one realises it is merely the sculptor’s art at work and not a predator, but word-plays carved on stone are never going to affect us at such an instinctive level.

For me this evolution-driven instinct is a form of visceral intelligence. Some people are worried that having the sub-conscious mind control our bodies in this way takes away free-will – I’m just glad there’s a bit of my brain getting on with coping with the world without me needing to worry about it!

So what for gardens then? I wanted to understand why I felt so deeply moved standing beside the sinuous mounds and lakes at Portrack, whereas the universe cascade staircase felt like a 1960s Butlins holiday camp. Perhaps in the case of the earth mounds the simple, powerful manipulation of space is registered unconsciously in those place cells of the hippocampus affecting us at a fundamental level, whereas the symbolic and written components of the more complex structure cannot communicate directly with the sub-conscious but need to be processed by higher cerebral levels, bringing in all those other consciously-remembered associations of blocky white concrete as well. Those associations may well be very different for each observer … and individual elements of conscious symbolism may not work at all for some observers (Tony Heywood’s urban installation gardens really turn me off.)

Is this why, when visiting Little Sparta last year, I found the large-scale structures on the exposed hillside both moving and exhilarating (although that may have just been the horizontal rain and freezing wind) but some of the smaller installations by the house had that element of A-level art class angst that rather put me off? The larger elements work with space and place, giving their physical presence subconscious meaning, their textual presence works with the conscious mind a fraction of time later (‘little fields, long horizons’). The conflict-based sculpture doesn’t work for me – but an observer who has actually been in a war-zone may find the associations very meaningful indeed.

So for me ‘thinking gardens’ are divided into two – the ‘idea gardens’ which tickle and amuse the controlled consciousness and the ‘deep-feeling gardens’ that work with these unconscious pathways, with the pre-programmed ‘sense of place’, with this visceral intelligence – they communicate at a level faster and more basic than consciousness can operate. When I was shaping-up these ideas on unconscious communication I tried to express that thought to Anne (Wareham) who replied – “isn’t that just a description of good art?” It’s rather galling to discover you guys knew this all along and we scientists are still playing catch-up. Oh well, at least I know what a fractal is…

Jenny Woods – garden designer, gardener, writer, RHS lecturer

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