Like Humans, Monkeys Synchronize Their Behavior; Monkey See, Monkey Do!

It seems that the phrase, "monkey see, monkey do," is getting a whole new meaning. Researchers have found that, like humans, monkeys can synchronize their body movements without any conscious effort.

Researchers from the RIKEN Brain Science Institute in Japan have found that pairs of macaque monkeys will spontaneously adjust their movements to reach synchrony. This behavior has also been witnessed in humans, who will adjust their gait to be in sync with those walking around them, or will slow or speed up their claps during applause to match others in the audience. It's thought to reflect bonding and facilitate human interaction.

Naotaka Fujii and colleagues first trained macaques to push a button with one hand before conducting the experiments. Then, the researchers paired the monkeys facing each other while recording the timing of the push-button movements. They then placed the monkeys in front of a video screen of other monkeys pushing buttons, and in the last trial, the monkeys were placed by themselves.

The researchers found that the macaques modified their movements to be in-sync with their partners. They would either speed up or slow down, depending on what they saw. In addition, the scientists noted that the same was true whether the macaque was interacting with a live partner, or one on video. In addition, researchers found that this synchronized behavior could not have been learned by the monkeys during the experiment, since previous research had shown that it is extremely difficult for monkeys to learn intentional synchronization.

This new research could open the door to further neurophysiological studies of spontaneous synchronization in monkeys. It could further allow researchers to understand human behavioral dysfunctions such as autism, echopraxia and echolalia.

The study was published in the journal Scientific Reports.