Better by design.

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Humans

How interior design choices can boost your mental and physical health

Neuroscientists have figured out what interior design choices, from flooring to lighting, can help create homes that improve our mental health, decrease stress and fatigue, and even spark creativity

13 April 2022

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By David Robson

Leonie Bos

YOU might recognise the sensation from visits to a friend’s house – the feeling that a space is good for you. Perhaps it is a sense of profound relaxation, as if you left your worries at the door. Or you may have found the perfect office space that leaves you buzzing with creative ideas. Yet try to explain why you felt that way, or recreate those effects at home, and you fall short.

According to the ancient Chinese practice of feng shui, there are rules of harmonious living that affect the flow of energy through your body, and many modern design gurus take a similar line, dishing out guidance in lifestyle magazines and Instagram accounts. They advise on the shape of rooms, materials in furnishings, colours on walls and organisation of books – it may make your home look good, but does it make you feel good?

While there is nothing wrong with going with your gut when it comes to decor, there could be a better way to make design choices. A growing number of neuroscientists are collaborating with architects and interior designers. With carefully controlled experiments using objective physiological and psychological measures, they are starting to systematically test the influence of design elements on brain and body.

The work couldn’t be timelier. The rise of remote working has meant more time at home for many. Whether you want to boost your mood, lower your blood pressure, decrease your bad habits or ease the burden of dementia, this research can provide evidence-based strategies to optimise your living space for your physical and mental health.

The roots of this work lie in a field called neuroaesthetics. In the 1990s, neuroscientists began to explore the brain processes underlying our sense of beauty in art and music. They have shown, for instance, that the brain’s amygdala preferentially processes blurred images, showing heightened activity before we are even aware of what we are seeing. This is thought to be due to the region’s role as an early warning system, detecting threats in the peripheries of our vision (which are inherently blurry). The soft contours of impressionist art trigger this pathway, offering a hotline to the brain’s emotional processing that bypasses our conscious preferences and triggers an emotional response.

Over the next two decades, the focus of attention expanded from fine art to design – spearheaded by a conference at the faculty of architecture at the University of Dresden, Germany, in 2010. “We got to hang out with all these architects and designers,” says Oshin Vartanian, a psychologist at the University of Toronto. “We left this meeting with tremendous enthusiasm that this was something to go after.”

Much of the initial research explored the way our evolutionary history may have shaped our reactions to certain indoor spaces. According to one branch of evolutionary psychology, which biologist E. O. Wilson referred to as the “biophilia hypothesis”, we are drawn to living things – such as the sight of foliage and fruit or the sound of birds – and that this tendency has, in part, a genetic basis. This love of nature would have been adaptive, since other organisms could be sources of food or danger. Consequently, our brains still find natural scenes effortlessly fascinating – they can capture our attention without us having to deliberately focus on them. According to “attention restoration theory”, this can help to recharge the mind when it is stressed. Experiments in adults and children have shown that environments that stimulate unconscious attention allow parts of the brain responsible for directed attention to rest and recover from mental fatigue. “The effects are similar to those of meditation,” says John Spengler, a professor of environmental health and human habitation at Harvard University. As a result, we find scenes from nature particularly restorative – and designs that incorporate natural elements into homes and offices should have knock-on benefits for our physical and mental health.

Indeed, many studies now support that idea. Hospital patients whose rooms overlook natural settings tend to need lower doses of painkillers, and leave hospital earlier, than those whose windows look out over a brick wall, for instance. Other research has found that green views – in this case, of a flowering rooftop meadow – seem to restore students’ ability to mentally focus, compared with those looking out over a bare roof.

 

Natural elements – real or fake – allow the brain to recover from mental fatigue

Dimaberlin/Shutterstock

Faking it

We don’t all have the luxury of a lush vista, of course. But evidence is building that a naturalistic interior design can bring about the same benefits, even if we live in a concrete jungle.

Some of the most compelling comes from Jie Yin at Tongji University in Shanghai, China, who has used immersive virtual reality (VR) environments to test the benefits of different biophilic designs.

Spengler, Yin and their colleagues first created four separate office designs. One was a standard room without any natural elements. The second had an outdoor view and shelves with houseplants. The third had wallpaper with foliage print and a sculpture taking the form of a tree’s branches. The fourth was similar to the third, with the addition of several real plants dotted around.

They then asked participants to navigate the VR rooms for about 10 minutes while wearing monitors that measured their cardiovascular activity. Compared with the standard room, all the biophilic offices reduced blood pressure. It didn’t seem to make a big difference whether the contact with nature came through a window or whether it was part of the interior design.

Testing the idea further, Yin, Spengler and their team have since measured the ways that interiors can help people to recover after a mildly stressful event. Using a similar set of VR rooms, participants had to perform difficult mental arithmetic and take memory tests with a loud buzzer sound signalling incorrect answers. Once again, he found that the natural elements helped the participants recover after the challenge – resulting in a more rapid decline in blood pressure, compared with those exposed to the standard office design.

These were only short-term experiments, but quicker stress recovery could be a big deal for overall health in the long term, since elevated blood pressure is a known risk factor for cardiovascular disease. At the very least, this research might encourage us to source a few more house plants. But there are many ways in which we might incorporate biophilic elements into our homes and offices – including a greater use of natural materials.

For instance, Xi Zhang at Shanghai Jiao Tong University in China and his colleagues asked participants to work on a laptop for around 30 minutes in rooms in which interior walls were either exposed wood or painted white. Overall, the participants reported feeling much happier in the rooms with wood on display, and felt less fatigued at the end of their work.

Wood, it turns out, appeals to several of our senses. Other studies have shown that the feel of wood decreases blood pressure compared with aluminium and plastic, which both tend to increase blood pressure. There is even some early evidence that the mere smell of certain woods can be relaxing.

Dementia-ready homes

A new approach to housing design is especially important for the UK’s ageing population. Last year, the UK government released a report outlining the need for more “dementia-ready” housing. Recommendations include guidelines on improving community support, but there are practical design tips too. These include ensuring that signs in communal areas avoid icons, such as the green running man for the exit, which might be confusing for people with memory lapses.

They also recommend the strategic use of recognisable landmarks, such as trees and street furniture. Landmarks can also be used inside the home, such as a large pot plant or a striking painting. Brain studies have shown that good navigation strongly relies on our ability to recognise and remember landmarks, so increasing the number of permanent landmarks inside and outside the home should be helpful for people experiencing cognitive decline.

Dementia-ready housing could also incorporate some biophilic elements inspired by nature, together with increased access to natural light. There is strong evidence that this can help to reduce the incidence of depression, which is generally higher among people with dementia.

Make space

That’s the decor sorted, but perhaps our evolutionary history should also play into the way we design the layouts of our buildings. If you have ever found open-plan living appealing, you might be unknowingly tapping into something called “habitat theory”. This is the idea that we have a preference for larger, open spaces dotted with smaller areas of cover because of the fundamental visual properties of our ancestral home, the savannah. “The idea is that it would have been beneficial for you to be able to see across a vista, so that you could react easily if a potential source of danger was approaching,” says Vartanian. “But it had to be paired with somewhere to hide.”

Vartanian says there is now good evidence that these biases shape our responses to certain spatial designs. Views of smaller, enclosed spaces tend to produce heightened activity in the brain’s anterior midcingulate cortex, which typically responds to threat, he says. And when participants view photos of open-plan rooms in brain scanners, the images preferentially trigger activity in brain areas involved in visual exploration – a much more relaxed state of mind.

Once again, these differences could have important physiological consequences, particularly when you are already feeling anxious. Using VR, Lars Brorson Fich at Aalborg University in Denmark and his colleagues asked people to take part in a challenging public-speaking task within an enclosed or open-plan room. They found that the participants in the open space showed less severe spikes in the stress hormone cortisol, compared with those in the closed space.

That could be worth considering if you are planning a home working area and have the luxury of open-plan living. In the short term, opening up interior space may just lead you to feel a bit less on edge. After all, too much stress has been linked to numerous physical and mental conditions, including obesity and cardiovascular disease.

Neuroscientists don’t have all the answers, however. Something you might want to leave to instinct is the temperature of your environment, for instance. Small studies show that people are better at performing tasks that test working memory – your ability to hold and manipulate information in your mind – when a room is at their preferred temperature, potentially leading to improvements in efficiency and productivity. Of course, the ideal temperature may be a trickier call when sharing a home-working space with a partner.

Your unique preferences can also be let loose when it comes to colour. While you might have heard that certain colour schemes can influence cognitive performance, larger analyses tend to suggest the effects are minimal. On the other hand, there is strong evidence that the lighting schemes we use can influence things like creativity – so dimmer switches might be a good investment.

More generally, you should be mindful of the overall visual complexity that you are creating; natural designs may be soothing, but can be in danger of looking too chaotic without some kind of organising principle, such as symmetry or repetition. Such small tweaks – while seemingly irrelevant to human behaviour – could influence our actions in profound ways, says Ingrid Fetell Lee, author of Joyful: The surprising power of ordinary things to create extraordinary happiness.

She highlights a study by researchers at the University of Chicago, in which participants were shown various designs, some of which looked visually chaotic and jarring, with asymmetrical features. “They weren’t dirty or littered,” says Lee. “They were just architecturally funky.” Incredibly, participants shown chaotic designs were more likely to cheat when grading themselves on a maths test, compared with people who had viewed more ordered images. There is even evidence that orderly environments can encourage healthier eating, too.

We can only read so much into these findings, which examine the short-term effects of order in our environment, but studies investigating the opposite end of the spectrum – clutter – also support the idea that an ordered home has benefits. There is a significant link between procrastination and clutter in your environment, for instance. Several experiments show that a cluttered home is also linked to increased levels of cortisol throughout the day. It may be that the clutter itself isn’t the stressor, but the thought of having to keep up appearances. Regardless, creating a bit of visual order seems worthwhile. Even something as simple as reorganising your books according to colour can be a way of creating more order in a room, says Lee.

Finally, it may be helpful to find ways to fine-tune the ambience, so that you feel you have more control of your environment. One study at an insurance company in Wiscons in used technology that allowed individual employees to control the lighting and ventilation of their workspace, which significantly increased productivity by a few per cent. This may, in part, be due to greater physical comfort – but further studies suggest that the mere illusion of control over our surroundings can help us to feel better, even when the ambience itself doesn’t substantially change.

And while you are thinking about all these changes, don’t forget the importance of individuality. While environmental psychology might offer solutions for reducing stress, instilling discipline and improving productivity, remember there are always exceptions. So if that oversized, shiny Harley-Davidson motorcycle on display in the corner of your living room brings you a spark of joy, it is OK to occasionally drop the rulebook (as long as you quickly return it to its correct position on your colour-coordinated bookshelf).

Change your light to think better

Unless we are creating soft lighting for a romantic meal, it is easy to ignore the subtle ways that lights can influence our mental state. But a series of studies have shown that it can profoundly influence thinking.

Anna Steidle and Lioba Werth at the University of Hohenheim in Germany, for instance, found that bright lights – of 1500 lux – encourage a greater sense of self-awareness, which, in turn, leads to more reflective thinking.

Dimmer lights, in contrast, tend to make us less self-conscious – which psychologists have discovered can promote a more experimental mindset that suits freewheeling problem solving. Participants in dim settings found it easier to solve the famous candle problem, for example, in which they are asked to fix and light a candle on a wall so that the wax doesn’t drip on the floor, using a box of matches and a box of thumbtacks as their only tools. The correct solution requires emptying the box of thumbtacks, placing the candle inside and then using a thumbtack to attach the box to the wall.