Marmoset Parents Teach Their Kids Not to Interrupt

No one expects a human infant to slide into the world with a good grasp of grammar. Marmosets, another kind of chatty primate, are also poor conversationalists when they're young. But their parents seem to teach them how it's done. Young marmosets learn the cardinal rule of having a conversation: don't interrupt. And if they mess up, their parents give them the silent treatment. Common marmosets (Callithrix jacchus) live in large family groups in the forests of Brazil. "Because marmosets live in dense forests and are very small, it is difficult for them to maintain visual contact," says Cory Miller, a psychologist and neuroscientist at the University of California, San Diego. So the little monkeys call to each other often, using a variety of yelps, trills, and whistles. "These vocal exchanges are essentially social interactions," Miller says. So there are rules about how they should go, just as there are ...