Chimps may have theory of mind
Chimpanzees avoid telling their friends the bleedin' obvious, new research shows.
German and Scottish researchers say that when making alarm calls, they take into account the knowledge of other group members.
The team, from the Max Planck Institute for Evolutionary Anthropology and the University of St. Andrews, studied wild chimpanzees in Uganda and found that they called out an alarm over a snake if the other chimps around didn't know about it.
If the other members of the group had already seen the snake, they were much less likely to do so.
"As these highly camouflaged snakes sit in one place for weeks, it pays for the chimp who discovers it to inform other community members about the danger," says Catherine Crockford, a researcher at the University of St. Andrews.
The finding, say thew researchers, has implications for the development of language in humans. It suggests that the ability to communicate new information to others was already present when our common ancestor split off from chimps six million years ago - earlier than most anothropologists previously believed.
Recognizing another individuals' knowledge and beliefs is known as the 'theory of mind' - and it's long been unclear whether it's unique to human beings. Most animal studies have been conducted in captivity and have yielded conflicting results.
"Chimpanzees really seem to take another's knowledge state into account and voluntarily produce a warning call to inform the others of a danger that they do not know about," says team member Roman Wittig.
"It is as if the chimpanzees really understand that they know something the audience does not - and they understand that by producing a specific vocalization they can provide the audience with that information."