Humans Are Designed to Think While Walking
One of my favorite things to do when I am on vacation is hike in the mountains and take in as much scenery and contact with wildlife as possible. The former requires that I stay in good enough physical conditioning that I can achieve 15+ miles of mountain hiking per day. Therefore, when I am not on vacation, I go for a two-to-four-mile run every day before breakfast. That morning routine keeps me in physical shape and prepares me to undertake the research and writing projects for that day.
During my morning runs, I think about deductions I can draw from recently read research papers, I perform calculations that will be needed for the articles and book chapters I am working on, and I attempt integrations of various Bible texts and science research papers. Sometimes, I get so caught up in these mental endeavors that I end up adding another half mile or mile to my run.
Among Earth’s animals, this capability to multitask by engaging in complex thought while walking, hiking, or running is unique to human beings. A new study published by four Canadian biologists led by Megan McAllister establishes the details and scope of this capability.1
Simultaneous Walking and Thinking Experiments
The team performed a variety of tests on eight adult volunteers. They had the volunteers walk on a treadmill while fitted with an exoskeleton. The exoskeleton was a powered leg brace that the team used to add variable pressure to the volunteers’ lower limbs. While so suited and experiencing variable pressure on their legs at varying treadmill speeds, the volunteers concentrated on listening to a series of tones and evaluating the pitch of each by pressing buttons with either their right or left hands.
McAllister’s team consistently observed that no matter how distracted the volunteers were, they always quickly adopted the most energy-efficient and stable walking strides. On the tonal identification tests, the volunteers scored just as well when experiencing variable stresses on their leg muscles while walking as when they were not experiencing variable leg muscle stresses or when they were not walking at all. The team also noted that the volunteers—regardless of the degree of variable stresses on their leg muscles while walking—were unaware of the changes they made in their walking gait. McAllister and her colleagues determined that finding the most efficient and stable way to walk is an automatic activity that does not disturb complex thinking. They concluded that energy optimization while walking involves implicit mental processing that allows attentional mental resources to be fully directed toward challenging cognitive objectives. As McAllister commented, “When people adapt to energy-optimal ways of walking, they do so without having to consciously think about it.”2
The research group discussed how their experiments show ways that post-injury rehabilitation practices could be improved to deliver faster and more effective recoveries. Beyond that application, there are design and philosophical implications.
In addition to the capability of engaging in sustained complex thinking while walking at different rates through a variety of natural and artificial terrains, humans also engage in complex communication with one another. I can recall, for example, hikes I took with Caltech astrophysicists in the Sierra Nevada Mountains during which we would discuss and solve research problems we were working on.
The human capability of engaging in sustained complex thinking and communication while traversing large distances of rough terrain may have been a significant factor in explaining the relatively rapid extinction of nonhuman bipedal primates upon the arrival of humans into their habitats. It certainly would have given humans an enormous advantage in procuring food and shelter. It likely was a major factor in explaining why humans alone, among the approximately dozen different species of bipedal primates, were not trapped in technological stagnation but demonstrated sustained, rapid technological advance.
The multiple distinct purposes for which God created humans that I discuss in my book Why the Universe Is the Way It Is require that God endow us with the capacities to multitask in many different ways.3 McAllister’s team has established the scope of one such capacity. I predict that scientists will soon establish the scope of several other such multitasking capacities.
Such advances will continue to add to the accumulating scientific evidence that humans are exceptional—distinct from the rest of Earth’s animals, present and past. We alone are created and designed in the image of God (Genesis 1:26–27). As image bearers we are endowed with the capabilities of managing all Earth’s resources for the benefit of all life. We are also capable of discovering and forming a relationship with God and of being prepared for future endeavors in the new creation.
- Megan J. McAllister et al., “Energy Optimization during Walking Involves Implicit Processing,” Journal of Experimental Biology 224, no. 17 (September 14, 2021): id. jeb242655, doi:10.1242/jeb.242655.
- Quoted by Kathryn Knight in “Walking Efficiently Takes Next to No Thought,” Journal of Experimental Biology 224, no. 17 (September 14, 2021): id. jeb243349, doi:10.1242/jeb.243349.
- Hugh Ross, Why the Universe Is the Way It Is (Grand Rapids, MI: Baker Books, 2008), 154–163.