A state-of-the-science survey of how our brains enable our bodies to do their work.
When we walk toward a wall, why don’t we smack into it? Because the body has an “intelligence” that enables us to do things like translate signals about distance, materiality, proprioception, and related matters that, writes Grafton (Chair, Neuroscience/Univ. of California, Santa Barbara), “are almost primordial in their simplicity” but that encompass the whole history of evolution, “stretching all the way back to the appearance of the most basic forms of locomotion in vertebrates.” The concept of “physical intelligence” is something that has tended to be studied only in its superlative sense, in the performance of top athletes or persons placed under the most extreme of environmental conditions. In everyday cases, the mental processes used for our actions “are, more than anything, different kinds of learning machines that the brain has available for acquiring and maintaining physically derived knowledge.” A climber and distance hiker, Grafton takes many of his examples from his own experiences outdoors under conditions that sometimes invite taking things for granted but that instead require constant vigilance, the mind connecting sensory information to appropriate responses—appropriate because, so often, doing the wrong thing can lead to disaster. All of this requires sophisticated neural circuitry that in turn yields a kind of “sixth sense” whose discovery has fueled debate among philosophers and brain scientists for decades: “How could a person consciously and willfully move while being utterly unaware of her own body’s movements?” Arriving at an answer deepens our understanding of this sixth sense of movement, which turns out to be more important than the other senses in getting us around in the world. It involves such complex mental processes as being able to “conceptualize dynamic force” and areas of the brain that range from the higher-reasoning cortex to the elemental cerebellum, which "keeps track of a massive list of comparatively minor adjustments or tweaks to each movement to make them work well under a variety of conditions.”
A well-written exploration of the mind-body connection.