Chapter 4
The Art of Bipedal Movement: Learning to Walk
Walking may seem like the most natural thing in the world, yet it represents an astonishing neurological and physical achievement requiring extensive training and practice. Unlike foals or gazelles that must walk quickly after birth for survival, humans are born with only the propensity, not the capacity, to walk. We must learn through experience to develop the neural circuits that enable lifelong bipedalism.
Karen Adolph's research reveals the remarkable process of learning to walk: children take thousands of steps and experience dozens of falls daily, using these failures to refine their technique. The average toddler takes 2,368 steps, travels 701 meters, and falls seventeen times hourly. Over 300-400 days, children might take hundreds of thousands of steps and experience thousands of falls, with falls decreasing as expertise grows.
Unlike language acquisition, which requires a community, walking emerges largely from innate motor programs in the spinal cord and brain. Studies show that crawling expertise predicts walking proficiency. Crawling develops crucial muscle groups and coordination patterns that support walking. This extended learning period-playing across varied terrains and surfaces-provides the training needed to develop unconscious adult-level walking skill.
Walking upright requires remarkable balance-staying perpendicular to the ground while adjusting to changing surfaces and traction. The brain circuits used for imagined walking closely resemble those used during actual walking, with additional motor regions engaging only during physical movement.
The brain views the body as hanging down from the head rather than built up from the feet. Standing upright requires continuous postural control to prevent toppling, as our line of gravity shifts with movement. The head functions as an "inertial guidance platform," maintaining a relatively flat, parallel-to-ground position despite terrain changes.
This balancing act relies on the vestibular system in the inner ear, which uses semicircular canals and otoliths to detect movement in three dimensions. These structures convert motion into electrical signals through tiny hairs with crystals that move in fluid. Unlike visual systems, the vestibular sense operates even during sleep, providing lightning-fast reflexive responses to slips or falls before conscious awareness.
Walking fundamentally depends on rhythm, functioning like an "inverted double pendulum" where the body swings over a stiffened limb during each step. This rhythmic movement emerges from extraordinary collaboration between top-down brain control, bottom-up input from feet and legs, and mid-level spinal cord "central pattern generators" (CPGs)-neural circuits producing regular rhythmic motor patterns.
Walking also requires knowing where your foot is without constant conscious attention. Beyond our brain's cognitive map for navigation, we possess an acute sense of our body's position-proprioception, our "sixth sense." This system monitors ankle, knee and hip joint positions and signals from muscles and ligaments, creating our standard walking experience where the world appears to flow past us as we move forward.
Chapter 5
Finding Our Way: The Brain's GPS System
Finding our way through the world involves sophisticated cognitive processes beyond simple mechanics. Dead reckoning-estimating position based on speed and direction from a known point-is fundamental to navigation for humans and other species. Though imperfect without environmental recalibration, this "path integration" allows us to navigate even unfamiliar territory by combining self-centered orientation with environment-centered awareness.
Contrary to intuition, vision isn't essential for navigation. Experiments with congenitally blind, adventitiously blind, and blindfolded sighted participants reveal that all groups can perform simple and complex navigation tasks with similar proficiency. The brain constructs a "cognitive map" from multiple sensory inputs, not just vision.
This spatial sense functions like a "silent" operating system-we're unaware of it until it fails. It's built from walking experience and activated most effectively at walking speed. The hippocampal formation receives input from all senses plus motor feedback, creating an environmental map that works regardless of which particular senses are available.
The concept of cognitive maps originated with Edward Tolman's studies of rats in mazes. He investigated "latent learning" by allowing rats to explore mazes with occasional food rewards, then blocked certain routes to observe their responses. Challenging the dominant stimulus-response behaviorism, Tolman discovered rats developed internal "survey maps" of their environment, enabling them to solve navigation problems flexibly.
Without reliable visual cues, humans systematically veer off course. Experiments in forests and deserts showed that without celestial references like the sun or moon, people inevitably walk in circles. Virtual reality studies reveal we consistently underestimate travel times while overestimating straight-line distances-the "it won't take long" fallacy. Yet despite these navigational challenges, humans possess remarkable wayfinding abilities, drawing on landmarks, memories, and hard-to-articulate instincts to navigate successfully.
The brain's navigational system centers on place cells that form our cognitive map, telling us where we are and working best when we're walking. These cells show directional preferences-firing when moving one way but not another-which explains why we get lost when this feedback is missing. O'Keefe's groundbreaking discovery of place cells was followed by Ranck's identification of head-direction cells that function like a compass. The Mosers discovered grid cells that provide spatial metrics, completing the core GPS system.
Additional specialized cells track boundaries, object distances, movement speed, and upright position across multiple brain regions. This GPS network enables coherent walking and is evolutionarily conserved across species. The system activates through movement like walking, supporting not just navigation but also mental time travel and predator avoidance through "latent learning" of safe refuges.
Chapter 6
Urban Pathways: Walking in the Modern World
Walking is the optimal way to truly know a city-its energy, smells, sights and sounds that remain hidden when driving. With over half the world's population now living in urban areas (projected to reach 80-90% by 2050), city walkability has become crucial. Studies show that higher walkability correlates with lower activity inequality and reduced obesity rates. Cities like San Francisco, with higher walkability scores than comparable California cities like San Jose and Fremont, demonstrate lower activity inequality.
Urban planner Jeff Speck argues that the best city walks must be useful (daily necessities within walking distance), safe (pedestrians protected from vehicles), comfortable (streets as "outdoor living rooms"), and interesting (unique buildings with signs of humanity). Urban green spaces like Hyde Park or Central Park fulfill these criteria perfectly, and research shows these spaces remain relatively stable despite population growth.
With aging populations living longer than ever before, cities must adapt to accommodate slower walking speeds and mobility challenges-84% of older males and 94% of females walk below the standard 1.2 meters per second assumed for road crossings. Walkable cities also generate economic benefits through increased social interaction and local spending.
Studies show city dwellers generally walk faster than those in smaller towns, possibly reflecting economic vitality and competition for resources. The relationship between population numbers and density's effect on walking speed remains complex. Places like London's Oxford Circus slow movement during rush hour, while nearby streets flow more easily.
Cities accelerate our pace through economic rewards and competition. Our brains calculate effort versus reward, seeking to minimize the former while maximizing the latter. We'll walk faster toward greater rewards-greeting your child versus a colleague at an airport-and cities offer abundant rewards we must compete for, like restaurant tables or train seats.
In bustling cities, we must predict others' movements to avoid collisions. We unconsciously coordinate walking speeds when in pairs or groups. "Walking rage" emerges when pedestrians impede others' progress-though social norms typically prevent confrontation.
We navigate crowds using an invisible force field, gathering information from others' feet, body trunk, shoulders, head position, and especially eye gaze. When someone wears sunglasses or looks at a device, our predictions falter. Virtual reality experiments confirm eye gaze importance, showing how brain regions process this social information to predict movement trajectories.
The Italian tradition of passeggiata-the sociable evening stroll through town-exemplifies the best of urban walking. For this to flourish, cities must be designed with EASE: Easy to walk, Accessible to all, Safe for everyone, and Enjoyable. The steps to make our cities walkable are straightforward-we simply need to take them.
Chapter 7
Nature's Medicine: Walking for Physical and Mental Health
Movement, especially regular walking, profoundly benefits both body and mind. Regular walkers report feeling sluggish and down when deprived of their walks-science now confirms this isn't mere anecdote. Despite Hippocrates claiming "walking is the best medicine," modern humans spend 87% of their time indoors, with some calling sitting "the new smoking."
This sedentary lifestyle damages not just our physical health but our personalities. Studies show inactivity correlates with negative changes in three of the "Big Five" personality traits: decreased openness, extraversion and agreeableness. While the exact mechanism remains unclear, the cure is simple: get up and walk.
Walking immediately alters blood pressure, circulation, and metabolic rate. Regular, brisk walking exercises the heart, benefiting the head-heart axis that directs 20% of cardiac output to our oxygen-hungry brain. Similar effects occur in the gut.
Where we walk matters profoundly. As urban populations grow, green spaces become essential for well-being. Historical architecture recognized this need-monastery cloisters (derived from ambio, "I walk in a circle") and walled gardens provided protected outdoor walking around nature. Modern buildings could incorporate similar features to connect us with the natural world.
Yet we consistently underestimate our need for nature. A Canadian study comparing tunnel walks versus outdoor riverside walks found participants significantly underestimated how much better the nature walk would make them feel. The outdoor walk improved mood scores by about one-third compared to indoor walking-demonstrating our poor "affective forecasting" abilities.
The Japanese tradition of forest bathing (shinrin-yoku) exemplifies our deep connection to nature. Scientific evidence confirms that regular exposure to nature positively affects health in measurable ways. In deprived areas of Dundee, researchers found residents without access to green spaces lacked the normal daily decrease in cortisol (stress hormone) levels.
According to "attention restoration theory," restorative natural environments should provide three elements: removal from normal surroundings, fascinating sensory elements, and expansiveness. A UK study of 4,255 participants found coastal environments most restorative, followed by countryside and urban green spaces. Importantly, well-designed urban parks can effectively substitute for countryside experiences if they incorporate wilderness areas and natural pathways rather than just manicured lawns.
The positive effects of nature exposure on mood apply universally across ages, genders and cultures. Remarkably, the impact of nature exposure on happiness is comparable to factors like income, education, religiosity, marital status, volunteering and physical attractiveness. While changing income or attractiveness may be difficult, walking in nature is accessible to almost everyone and provides lasting benefits to happiness and well-being.
There's a crucial distinction between temporary low mood and major depressive disorder (MDD), which the World Health Organization considers one of the greatest future health hazards. Studies demonstrate that walking can be comparable to drug treatments and cognitive behavioral therapy for MDD sufferers. Research tracking 33,908 mentally and physically healthy adults for eleven years found that even minimal physical activity-walking just once weekly-significantly reduced depression risk. The researchers concluded that approximately 12% of future depression cases could be prevented if everyone engaged in at least one hour of weekly physical activity.
Chapter 8
The Walking Muse: Creativity on Two Feet
Walking liberates the mind, clearing daily clamor and enabling problem-solving through quiet self-dialogue. This connection between bodily movement and mental flow has been recognized since antiquity-from the peripatetic philosophers of ancient Greece to Nietzsche's assertion that "Only thoughts reached by walking have value."
Throughout history, writers and thinkers have noted walking's relationship to creativity. Wordsworth composed "Tintern Abbey" during rambles, Kierkegaard walked himself into wellbeing and away from burdensome thoughts, and philosopher Bertrand Russell walked an hour each morning before writing "smoothly, easily and without a single correction."
Walking facilitates creative thinking by enabling efficient switching between different mental states-the ability to zoom in on specific thoughts and zoom out to see broader context. This reflects two essential brain work modes: the active, executive mode (focused attention on details) and the default mode (mind-wandering, autobiographical memory).
We spend substantial time mind-wandering-up to 10-15 minutes every hour-which isn't mere idleness but necessary mental housekeeping that integrates past, present and future while creating personal narratives. Walking creates a state of "active idleness" that facilitates engaged mind-wandering, allowing thoughts to range freely while maintaining directed physical action.
The brain system active during memory access-the extended hippocampal formation-is also active during walking and navigation. This shared neural network supports both episodic memory and spatial navigation, enabling creativity through novel associations as mind-wandering allows ideas to collide while focused thinking evaluates their value.
Walking affects different types of thinking in varying ways. While psychologist Daniel Kahneman notes that complex calculations requiring working memory (like multiplying 23 x 78) may be hindered by walking, ill-defined problems often benefit from ambulatory thinking. The contrast between Kahneman's experience and mathematician William Rowan Hamilton's walking-inspired quaternion discovery illustrates this distinction. Hamilton's "flash of genius" while walking between Dunsink Observatory and Dublin city center exemplifies how walking facilitates divergent thinking for creative problems.
Walking increases creativity by activating more brain regions simultaneously and enabling remote associations between normally disconnected neural networks. Stanford researchers Oppezzo and Schwartz demonstrated that walking (especially outdoors) dramatically increases performance on divergent thinking tests and metaphor creation compared to sitting. This effect occurs because walking demands greater brain activity across systems controlling balance, vision, and coordination while facilitating the collision of half-formed ideas into novel combinations.
Walking alters our perception of time passing. The walker's experience of time fluctuates between extremes: arduous uphill climbs in poor conditions make minutes feel like hours, while pleasant downhill walks in moderate temperatures create a "flow" state where significant distances pass with minimal perceived effort. This flow state-characterized by concentration, deep enjoyment, control, and immersion-represents an optimal psychological experience where the mind becomes liberated from moment-to-moment control of walking while still covering considerable ground.
Chapter 9
Collective Movement: The Social Power of Walking Together
While the author has avoided certain walks (pilgrimages, sleepwalking, walking the plank), many of their best walks have been social experiences with friends and family, particularly on cold, sunny days or at night when the mundane becomes transformed. Walking has a profound social function that's often unrecognized-we walk together for ideals, food gathering, social display, political change, better lives, or simply enjoyment. We've evolved to walk together, with social walking sending signals about shared intentions and collective goals.
Walking is frequently overlooked as a group activity, but our relationship with walking stretches back to deep time, evidenced by 19,000-year-old fossilized footprints of an extended social group near Lake Laetoli in Tanzania. Without such larger walking groups, there would be no reproduction, specialization, coordinated resource acquisition, or colonization of new places. Even solitary walks like pilgrimages have social dimensions, performed in solidarity with a greater purpose or community.
Walking together offers unique conversational opportunities that sitting together doesn't provide. As Mark Twain noted, while scenery and physical activity are important, "the supreme pleasure comes from the talk." Walking strengthens our connection to others and the world-studies show elderly people who walk about 150 minutes weekly are more socially active with better overall well-being.
Learning to walk fundamentally changes children's social interactions. Unlike crawling, walking allows direct eye contact without awkward postural changes. Studies show walking children play more with toys and vocalize much more than crawlers or those in baby walkers. Walking liberates both hands and minds, dramatically increasing opportunities for social interaction. Unlike car travel, walking creates common ground and shared experiences, enabling human-level interaction.
Social walking requires remarkable brain-body coordination to fall into step with others while maintaining common purpose. It demands simultaneous control of one's own movement while predicting others' trajectories-often while talking, singing or chanting. We find synchronizing with one or two others relatively easy, but larger groups require more conscious effort, often aided by natural leaders.
Sound plays a crucial role in coordinating larger walking groups-singing, chanting, or metronome-like beats help synchronize our movements. Studies show that groups walking to a regular beat (around 70 beats per minute-the average resting heart rate) maintain steadier pace with increased frontal lobe activity, the brain region involved in planning and intention.
Walking together for migration, exploration or protest is fundamental to human society-a collective expression absent even in our closest animal relatives. Research shows we experience psychological "effervescence" from being part of crowds assembled for common purpose-whether protests, concerts, religious gatherings or sports events.
This feeling of connectedness correlates with lower loneliness, higher positive feelings, greater meaning in life, and better self-awareness. People who experience high levels of social connectedness while walking generally report better life outcomes.
Mass walking demonstrations can sometimes transform societies. Gandhi's marches revealed how removing consent makes colonial power untenable. The American civil rights marches, coupled with legislative action, led to enduring changes. By walking together, we solve the collective action problem-demonstrating shared feelings about crucial issues through unified physical presence.
Chapter 10
Steps Forward: A Walking Revolution
Walking deserves central consideration from policymakers, medical professionals and urban planners. We need a walker's charter with straightforward principles and legal implementation. The EASE framework (walking should be Easy, Accessible, Safe and Enjoyable) should guide town planners and architects to improve our collective quality of life.
However, information alone isn't enough-otherwise there would be no smokers or anti-vaccination campaigns. A successful walking campaign needs simple behavioral change goals: ensuring walkable towns and cities, providing well-designed green spaces, and promoting walkers' needs as central to human mobility.
Our communities must be engineered to allow what comes naturally-opportunities for activity alongside places to rest and recharge. Creating, engineering and defending walking places and spaces remains our present and future challenge, one that will enrich us all in ways we've yet to discover.
In this book, we've journeyed deep into evolutionary time to meet our bipedal ancestors and witnessed how walking emerged repeatedly in nature. We've explored how cognitive maps prevent us from getting lost, functioning best when regularly activated through walking.
We've examined our modern cities, which can be walking paradises when designed with pedestrians in mind. As we become increasingly urban-dwelling, we must remember that cities should prioritize people, providing EASE for everyone from the elderly to the young, including those using mobility aids.
To implement these lessons, use walking apps with alerts to track your steps and compare with others. Simple changes like parking farther away or getting off public transport earlier can increase your daily walking.
Walking improves mood more than you expect, potentially inoculating against depression and negative personality changes from sedentary living. It also enhances problem-solving and creativity. The core message is clear: walking enhances every aspect of our social, psychological and neural functioning-a simple, health-building prescription we should take regularly. Whether in nature or urban settings, walking connects us to our evolutionary past while securing our future wellbeing.
