As children get older, they go beyond turn taking to find joy in perfect synchrony, doing the same thing at the same time as their partner. Girls especially come to delight in singing songs together, jumping rope together, or playing rhyming and clapping games (such as pat-a-cake) in which high-speed hand motions are perfectly matched between the partners while high-speed nonsense songs are sung at the same time. Such games have no explicit goal or way to win. They are pleasurable because they use the ancient power of synchrony to create communion between unrelated people.
