IMAGE (IMAGE) National Institutes of Natural Sciences Caption When two monkeys facing each other make repetitive arm movements at their own paces, their movements spontaneously become synchronized. Credit Saeka Tomatsu Usage Restrictions none License Original content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.