Monkeys, Like Humans, Can Synchronize Their Movements
Researchers in Japan have shown for the first time that pairs of macaque monkeys spontaneously synchronize their movement, just like humans.
AsianScientist (Jan. 28, 2013) - Researchers in Japan have shown for the first time that pairs of macaque monkeys spontaneously synchronize their movement, just like humans.
Humans unconsciously modify their movements to be synchronous with their peers. We adapt our pace to walk in step or clap in unison at the end of a concert, a phenomenon that is thought to reflect bonding and interaction among humans.
In a new study published today in the journal Scientific Reports and led by Dr. Naotaka Fuji of the RIKEN Brain Science Institute, the researchers tested whether pairs of Japanese macaque monkeys could synchronize a simple push-button movement that they had learnt prior to the experiments.
In a first experiment, the monkeys were paired and placed facing each other and the timing of their push-button movements was recorded. In the second scenario, each monkey was instead shown videos of another monkey pushing a button at varying speeds. And in the last experiment, the macaques were not allowed to either see or hear their video-partner.
The results show that the monkeys modified their movements – increasing or decreasing the speed of their push-button movement - according to their partner's movement, whether or not their partner was real or on video.
However, different pairs of monkeys synchronized their movements at different speeds, and the monkeys synchronized their movements the most when they could both see and hear their partner.
The researchers note that this behavior could not have been learnt by the monkeys during the experiment itself, as previous research has shown that it is extremely difficult for monkeys to intentionally synchronize their movements.
"The reasons why the monkeys showed behavioral synchronization are not clear. It may be a vital aspect of other socially adaptive behavior, important for survival in the wild," the authors write.
The research opens the door to further neurophysiological studies of spontaneous synchronization in monkeys, which may also help to explain human conditions such as autism spectrum disorder (ASD), echopraxia, and echolalia (a condition where patients uncontrollably imitate others).
Source: RIKEN; Photo: Asian Scientist Magazine.
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