What is it that makes us human?


Walking upright on two feet is a uniquely human skill. It defines us as a species. […] In this hymn to walking, neuroscientist Shane O’Mara invites us to marvel at the benefits it confers on our bodies and minds. […] Walking is good for our muscles and posture; it helps to protect and repair organs, and can slow or turn back the ageing of our brains. With our minds in motion we think more creatively, our mood improves and stress levels fall. Walking together to achieve a shared purpose is also a social glue that has contributed to our survival as a species.

Place cells

Neuroscientist John O'Keefe won a Nobel Prize for discovering certain brain cells in the hippocampus that broadcast a rat's location in a maze. Humans have these place cells too and they gather most data when we are walking.

Place cells can also have a directional preference and under certain circumstances will only fire when we are facing in one direction. Sometimes when we notice that we are lost, it’s because we have been walking for a while in one direction and our place cells aren't firing.

The Mobility-Productivity Paradox

Walkable cities promote economic and social encounters, both designed and serendipitous. O’Mara comments:

It has even been suggested by economists that the more car-bound you are, the less economically productive you are.

The evidence for this claim comes from The Mobility-Productivity Paradox: Exploring The Negative Relationships Between Mobility and Economic Productivity by Todd Litman (2014).

Pace of life

According to research carried out in 1999, Switzerland has the fastest pace of life, based on walking speed, postal speed and clock accuracy.

The research also shows that humans walk more quickly in cities than we do in the countryside, and we seem to walk more quickly in more wealthy cities than in less wealthy cities.

This is perhaps because the bigger economic opportunities are worth the extra effort. We hurry to get a seat on a busy train, for example.

Declining physical activity can change our personality

Stephan et al (2018) found that declining levels of physical activity over the course of twenty years were associated with statistically significant declines in the personality traits of openness, extraversion and agreeableness (n=8723).

The biggest effect was found on conscientiousness, but I don’t fully understand the paper’s abstract here. What is ‘baseline physical inactivity’ as opposed to ‘lower physical activity’?

Controlling for demographic factors and disease burden, baseline physical inactivity was related to steeper declines in conscientiousness in all three samples and a meta-analysis (β = −0.06)

Minimal physical activity can reduce our chances of depression (but not anxiety)

A large study in Australia, which followed 33,908 healthy people for 11 years, found that 12 percent of future cases of depression could have been avoided if everyone in the study had done at least one hour of physical activity, such as walking, every week.

The advantages of walking over running

With running, the risk of injury rises with the distance that you run. But with walking the risk of injury is more or less the same, no matter what distance you travel.

O’Mara says that, for maximum benefit, one should walk at 5-5.5kph for at least 30 minutes, 4-5 times a week.

On the importance of activity during isolation

A small, but intense study found that only three days of total inactivity (and it was total—the volunteers were lying in dry immersion tanks!) was enough to trigger decreases in muscle volume, viscoelasticity and performance (n=12). Although this is obviously nothing like the conditions of coronavirus quarantine, it’s motivation to stay active!

Academics who walk for thought

Every day I walk myself into a state of well-being and walk away from every illness. I have walked myself into my best thoughts, and I know of no thought so burdensome that one cannot walk away from it.
~Søren Kierkegaard

Bertrand Russell was also a great walker and in the morning would always go for an hour’s walk alone to prepare for writing.

According to a Norwegian study of nine academics who love to walk: a creative walk is one where the pace means your body is ‘engaged and stimulated, not overly taxed’.

Walking, memory and creativity

According to O’Mara, walking is a form of ‘active idleness’. Research has shown that active mind-wandering—such as that facilitated by walking—supports later creative problem-solving.

Walking and mind-wandering go together because the region of the brain associated with both memory retrieval and navigating an environment is the same. So walking helps us to flicker between (or activate simultaneously) the two modes of thinking necessary for creative thought: mind-wandering and mind-focusing.

Oppezzo and Schwartz (2014) found that walking generated both more and more creative ideas, compared to sitting down. And that walking outdoors generated more novel ideas than sitting down, walking on a treadmill indoors, and being pushed in a wheelchair outdoors. They discovered that there is also a ‘residual boost’ in creativity after the walk.

Social anxiety inhibits social synchronisation

In a synchronised finger tapping experiment, people with higher levels of social anxiety were less able to tap in time with others.

We get a buzz from being in a large crowd…

…Whether that’s a protest, a concert, a church service or a football match. Indeed, Gabriel et al. declare that:

connection to large, mostly anonymous groups is important for the fulfilment of psychological needs and a sense of psychological well-being.

The measure of ‘effervescent assembly’ developed by the study also predicts ‘decreased loneliness, increased positive feelings, a sense of meaning in one's life, self-awareness, and spiritual transcendence’.

Crowds are fun!


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  • Thanks to G.C. for reminding me that I’d already read this interesting book!

  • 183 pages, ~61,000 words

  • Read: 13 August 2019 to 24 March 2020

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Hello, I’m David Charles and I’m a UK-based writer and outdoor instructor. Say hello by replying to this email, or delve into I also publish a weekly newsletter that helps you make a little more sense of the world. Thank you for reading!