He altered the movement of one pendulum, but within a half hour the swinging weights had regained synchrony. When one of the clocks was moved to another wall, they gradually fell out of step. In the example of the applause, each person began clapping at his or her individual pace. As more members of the group started to applaud, individuals unconsciously slowed or speeded up their clapping to fit the general tempo. Synchronized oscillation is apparent in an astonishing array of biological systems.
Crickets sing in a shared chorus, and some species of firefly blink to a common pattern.
A group of untrained drummers scattered throughout a large room will soon fall into a shared beat. Even women who work together in the same office often experience their menstrual cycles at the same time. Systems of oscillators can be specific to a single organism. Separate pacemaker cells, for example, oscillate with different frequencies. But hundreds of them in the heart together beat with a common rhythm.