How Do We Synchronize Our Behavior?

By Chuck Dinerstein, MD, MBA — Aug 18, 2020
In addition to the multiple rhythms that underlie our individual lives, when we come together we tend to "synch" with one another. Whether it be as simple as adjusting the pace of our walking; the give-and-take of our conversation; or as seemingly sophisticated as the murmuration of starlings, it is a biologic phenomenon. How do we entrain, tie together, our independent rhythms?
Image courtesy of Sasin Tipchai on Pixabay

Synchronization of cells, so that they act in concert, is mediated by the chemistry and electricity, as neural impulses, in their environment. Cytokine storm, a feature of COVID-19 and other abnormal immunologic responses, might be the posterchild of asynchrony. That Internet lag that makes a Zoom conversation less than natural is another example. 

Does human synchronization rely solely on the environment and its clues, or is there a behavioral component? Because we are social creatures, the answer has implications to how we share, information, and more pertinent these days, disease. Trying to answer that question was the subject of a study recently published in Nature Communications. Studying synchronization is made difficult because there are so many channels providing information simultaneously. Consider applause by an audience, where rhythmic clapping may result from what you see, hear, and feel. How do you isolate and evaluate each component?

The researchers used a novel method, 16 violinists, sonically isolated by headphones, visually separated by partitions. As each violinist repeated identical musical phrases, the researchers were able to control what they heard, not only from their instrument but from one or two other violinists. The researchers were then able to alter which audio inputs were paired along with their strength and delay. 

The researchers first identified a strength of the signal; in this case, the volume of the other violinists playing that assured synchronization. As you might expect, the more connected one individual was with the network, the less volume was necessary to induce synchronization. Multiple weak signals were as powerful as fewer stronger ones. 

They then introduced a delay. With small delays, the playing slowed a bit to compensate. When the delay resulted in the violins being half "out of phase," the players synchronized with one following stably behind the other. Longer delays created a "frustrated state," where the violinist couldn't synchronize at all; as a result, the violinist ignored the additional input and returned to their intrinsic playing. 

Until this time, the theoretical underpinnings of network theory included a belief that in the presence of "frustration," a network member would split the difference and seek the average, to compromise. But the researchers found that we behaved differently, choosing to ignore the frustrating input. 

"In a state of frustration they don't look for a 'middle', but ignore one of the inputs. This is a critical phenomenon that is changing the dynamics of the network."

Moti Fridman, PhD

Unlike networks of cells, where synchronicity may be achieved by compromise, humans take actions and behave differently. We have seen this in the discussion of the early epidemiologic models of COVID-19 that project high overall mortality because they did not consider that some of the population would spontaneously protect themselves by social distancing.

Put in another context; we ignore what does not coincide with our beliefs. Part of the power of information, in this case, the sound of another violinist, is that it allows us to synchronize with our tribe. But at some deeper behavioral level, when our ability to synch up with our tribe is frustrated, by alternative information, we simply chose to ignore it, perhaps calling it "fake news." 

Source: Synchronization of complex human networks Nature Communications DOI: 10.1038/s41467-020-17540-7