You’re clapping along to a song with a friend. The beat speeds up. Without planning it, your hands switch from alternating claps to clapping together, just to keep up. Scientists observed the same phenomenon in simple lab tasks, where participants moved their fingers in response to a metronome. As the pace increased, one pattern transitioned into another and didn’t revert immediately, revealing two fundamental ways of moving and a natural “one-way” switch between them. 

According to Kelso, this flip isn’t just about muscles; it also reveals something about intention. In the classic experiments, participants were instructed to “do not intervene”—if the movement started to change, let it. That instruction makes any change count as “spontaneous,” and yet it also acts like a mental nudge to “let go.” The result is that tiny wobbles in the rhythm grow and help trigger the switch. Kelso calls these wobbles “fluctuations,” and he argues they can reflect your intention, not just random noise. In everyday terms, choosing to let the pattern change or to hold it steady is evident in those small timing shifts. 

Here’s the twist: telling yourself to “hold on” changes those wobbles. People can maintain a stable pattern for longer when they intend to, meaning the shape and size of the fluctuations adjust in accordance with their goal. That’s why Kelso says intention may be “hidden in the fluctuations.” As speed increases, those fluctuations typically swell before a switch (a hallmark of being near a change), and settling down can take longer as well. Think of cranking up the tempo on a workout track: the closer you get to your limit, the shakier it feels, and it takes a moment to steady yourself. 

Why does this matter for daily life? Because the same idea links body and mind. Kelso suggests we don’t need extra knobs in the theory to explain intention; the boundary conditions—your simple rule to yourself like “let go” or “hold on”—already tune the fluctuations. Once a switch occurs, systems often don’t revert right away, much like the momentum in your habits. That’s hysteresis in action. This dance between stability and change also shows up as we learn and explore, from finding a new rhythm to the way babies discover what their actions can do. In short, tiny changes in your timing can be purposeful signals of what you mean to do—and that’s a practical reminder that setting a clear rule for yourself can gently steer your mind and your moves.

Reference:
Kelso, J. A. S. (2025). The motionable mind: How physics (dynamics) and life (movement) go(t) together—On boundary conditions and order parameter fluctuations in Coordination Dynamics. The European Physical Journal Special Topics. https://doi.org/10.1140/epjs/s11734-025-01875-7

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