Recent Science Supporting "Why We Dance"

What evidence is there that "I am the movement that is making me"?

Posted Oct 31, 2015

Today I begin a new series of posts dedicated to sharing recently published scientific experiments that support the philosophy of bodily becoming I develop in my book Why We Dance. Why We Dance asks new questions about human persons—questions that attend to the active, agential role played by bodily movement in the process of becoming human. It makes the case that dance is vital to our humanity.

Every day since the book was published, I learn of a new study or research finding that pertains to some aspect of that argument. Every day, I see ways in which a philosophy of bodily becoming can help interpret the significance of these research findings, particularly with respect to understanding the irrepressible persistence of dance in human culture.

Today, I focus on three studies that support a principal claim of the book: I am the movement that is making me. This phrase serves as the centering node for my philosophy of bodily becoming; it marks the conceptual shift away from a mind over body sense of self that is required in order to make sense of dance as human.

What is remarkable about the claim is that it reverses the direction of causality that is assumed by much philosophy and science in the modern period in the relationship between “mind” and “body.” Here is it not the mind or brain (as central command) that controls and directs “its” body (in dualistic fashion). Nor is it the body, as a given material form, that determines the workings of the mind (as in mechanical materialism). Rather, I am the movement that is making me gives agency to movement itself as the prime ingredient guiding the development of characteristically human, self-conscious, relational, bodily selves.

While I could examine this claim at an infinite number of levels, from cosmic to microscopic, I focus today on movements made at a gross physiological level—movements humans make as relatively autonomous bodily selves. 

1. Fifteen years ago, a study of London cab drivers revealed a correlation between the cabbies’ spatial knowledge of the roads in London and the size of their hippocampi (a portion of the brain responsible for spatial memory). What they found was that the more experienced cabbies had a larger hippocampus. However, it was unclear whether or not humans with a larger hippocampus gravitated toward cab driving because they had a neural knack for it, or whether the act of driving through London had changed their brains.

In a study published last week in NeuroImage, researchers at Carnegie Mellon announced the results of their study to prove causality: that is, that the act of exercising spatial memory actually grew and rewired the circuitry of the brain.

In their experiment, Timothy A. Keller and Marcel Adam Just recruited 28 young adults to play a driving simulation game. One group practiced following the same route 20 times; while a control group practiced 20 routes for the same amount of time. Researchers scanned each participant’s brain using diffusion-weighted imaging (DWI—to measure water molecule movement), and functional magnetic resonance imaging (fMRI—to map brain activity).

The researchers found structural changes in the part of the hippocampus responsible for spatial learning (the left posterior dentate gyrus); they also found a greater synchronization of activity, or “frontal connectivity,” between this region and other sectors of the brain involved in spatial cognition. As Just reports: “We now know, at least for this type of spatial learning, which area changes its structure and how it changes its communication with the rest of the brain."

At first this study might not seem to have much to do with bodily movement. The participants were sitting, playing a game. However, spatial learning presumes a sense of one’s capacity to move in space—it is what we learn by moving our bodily selves. Further, participants were learning to make whatever hand-eye-bodily-self patterns of coordination they needed to make in order to move the game controls so that their sense of themselves (as vehicle) would move successfully. Their bodily movements were responsible for moving them through the space of the game.

The results, then, are significant for the principal tenet of Why We Dance: even the illusion of moving through space not only changed the brain of those who did it, it made them more able to sense and respond to a similar course in the future. It changed the medium through which participants interacted with the world.

Of course, questions remain. Was the change permanent? Did participants forget what they had learned a year later? Did the brain revert back? Would the changes be different if participants were actually driving through streets? What about if participants were walking on their own accord? Running? Biking? Would the spatial learning be different?

Even so, the study suggests that the physiological form of a human brain, its ability to connect with other aspects of the brain, and its ability to guide future actions are all a function of the bodily movements that a person is making. Form follows function. And the form that results becomes the raw material through which future function generates new forms.

2. A second study just published in the Journal of Neurophysiology complements this first—this one a study of actual dancers. In this experiment, researchers set out to determine whether or not the practice of ballet improves balance and coordination in general, outside of the studio, for those who practice regularly. Here the question focused on how the changes made as a result of spatial learning carry over into other areas of life—that is, in the words of Why We Dance, actually “make” a person who she is.

The researchers set up the experiment by focusing on groups of muscles called “motor modules.” The nervous system (brain, spinal cord, and nerves) uses these motor modules to attain a diverse range of motion. Researchers compared the gait and muscle activity of ballet dancers with ten or more years of training, to those of subjects with no dance or gymnastics training, as they walked across a wide beam and a narrow beam.

Not surprisingly, the ballet training made a difference. While subjects demonstrated similar gait patterns in navigating the wide beam; when it came to the small beam, the ballet dancers mobilized motor modules more consistently and efficiently than the untrained individuals. As researchers conclude, “training can affect control of every-day movements.”

At one level, this change seems obvious. Learning to dance is not just about learning to make particular steps. The act of learning a technique trains a bodily self  how to mobilize groups of muscles in order to take on new challenges, learn new movements, and travel farther along the trajectories of strength and agility that those movements represent. Those challenges may occur in a dance studio or in a scientific experiment.

The point here is that whatever patterns of movements we make train us to mobilize in the future whatever neuromuscular combinations we learned in order to make them. The movement patterns we make become us. The same is true for taxi drivers or scuba divers: whatever movements people make become the medium through which they sense and respond to whatever appears to them—where even that appearing is a function of the sensory education delivered by movements they have made. I am the movement that is making me.

Of course, here again questions remain. Were there evident changes in the brain associated with the use of those motor modules? To what extent did the dancers’ ballet experience prepare them emotionally or spiritually and not just physically for physical challenges? Is it only ballet that has this effect--what about other forms of dance or sport or bodily activity? Can we differentiate movement practices by the kinds of ordinary movements they exercise, amplify, and enable?

3. A final study, published on October 26, 2015, in the Proceedings of the National Academy of Sciences, supports these first two, suggesting that the very process by which neural systems (and perhaps humans) develop sensorimotor intelligence is a function—not of smart, controlling brains or determinative mechanical features but rather—of bodily movements made in relation to the environment.

In this study, Ralf Der and George Martius used two different “bioinspired robots”—a humanoid and a hexapod—to prove that an artificial neural network can develop “autonomous, self-directed behavior”—behaviour that is organized and even purposive, in the absence of any central control. These robots sport a simple neural system in which sensory inputs trigger motor outputs along jointed limbs that have an ability to bend and flex in human or insect-like ways.

Set in motion, without being given any specific task, the humanoids “learned” to crawl, turn a wheel, and even cooperate with one another. The hexapods learned to walk with several different gaits. The results, as the researchers explain, provide evidence for a novel rule governing “synaptic plasticity”: differential extrinsic plasticity (DEP).

According to this rule, every movement that a neural system makes evokes a new sensory input based on the interaction of body and environment. The sensations a neural system receives, in other words, are a function of the movement its bodily self is making. That sensation them becomes the cue for a new motor impulse that responds to the sensation. That response flows along the patterns of limb and joint organization that gave rise to the sensation. In this way, even though the neural system has no central brain, nor any ability to “remember” movement patterns, it nevertheless “learns” by virtue of this rhythm of sensing and responding.

Why We Dance exists to tease out the philosophical implications of such a finding. Of course, the robots in this study are bioinspired at the level of morphology alone. The range along which they can sense and respond is limited to touch. However, a philosophy of bodily becoming supports what the researchers themselves claim: the project is scalable. And, as Why We Dance suggests, especially in chapter 4 through 8, it is scalable along dimensions of experience generally distinguished from “the body,” including (the movement patterns represented by) feelings, thoughts, and spiritual aspirations. All of these dimensions exhibit the same rhythm of bodily becoming.

In addition, the authors of the study tease forth implications of this study for understanding evolution that align with the argument in Why We Dance. As Martius explains: "It is commonly assumed that leaps in evolution require mutations in both the morphology and the nervous system, but the probability for both rare events to happen simultaneously is extremely low. But if evolution was indeed in line with our rule, it would only require bodily mutations--a much more productive strategy. Imagine an animal just evolving from water to land: Learning how to live on land during its own life time would be very beneficial for its survival."

In chapter 2 of Why We Dance, I suggest that we should consider movement (as opposed to matter) as the agent and medium of evolution. This research study gestures precisely in this direction: the movements made by a bodily mutation impel further changes in neuro-physiological form. However, Why We Dance also takes a step farther by suggesting that those bodily mutations—or at least the ones that stick—unfold along trajectories of movement making that a given organism is already expressing.

Studies remain to be designed that would track how the need and opportunity to move pull into existence the forms that can. Nevertheless, the implications are intriguing—and nowhere more so than for a robust appreciation of human dance. For once we perceive evolution in terms of movement, then we are able to affirm dancing as a human effort to participate consciously in that ongoing evolution—whether we do so by growing spatially adept brains, exercising the motor modules required to survive in a given time or place, or simply learning to crawl.

I am the movement that is making me.