Of all the life on Earth, one of the most intriguing creatures to me is the sea squirt. The grown sea squirts look more like bulbous modern-art vases than living beings, but the baby sea squirt, which looks a little like a bubble with a tail, begins its life swimming around the ocean, equipped with a nervous system that's obviously smaller than ours, but remarkably similar in structure, including a brain. That system enables it to move and survive, responding to threats and remaining flexible. A sea squirt becomes an adult when it finds a nice rock to anchor to, and, having no need to move for the rest of its life, eats its own nervous system and brain.
Like the sea squirts’, our brains exist for movement. We would have no need of such complex and metabolically expensive thinking hardware if we didn’t have such variable and adaptable movement needs, particularly concerning the use of tools. While our brains can be used toward myriad ends—speech, imagination, art, invention, empathy, and many others—the foundational piece that arguably enables the rest is the need and desire to move. We have always needed to move for our survival, whether that was escaping predators, hunting, exploring new territory, or building shelters and tools. We didn’t become the apex predator because we were the fastest, strongest, or meanest creatures out there, it’s because we are the wiliest: humans are extremely adaptable, social, and skilled makers and users of tools. All tools we use fundamentally require movement, although our modern tools focus mostly the fine motor skills of the hands—still movement, technically, but barely enough to qualify anymore.
We each have this massive, intricate brain, designed for and craving movement and novelty, and we’ve stuck ourselves and our brains in a modern world where the demands are less of the deadly-predator variety and more often the perceived threats of deadlines, tests, and boss fights. All these amazing skills literally sitting there during both work and play, wasting away due to neglect. It doesn’t have to be that way–we’re all capable of amazing feats of movement, it’s just a matter of getting moving and going out to play.
References
Daniel Wolpert: The Real Reason for Our Brains (TED)
Stuart Brown, Play: How it Shapes the Brain, Opens the Imagination, and Invigorates the Soul