A new study has found that chimpanzees are more likely to alarm call to a snake in the presence of unaware than in the presence of aware group members, suggesting that they recognize knowledge and ignorance in others.
Many animals produce alarm calls to predators, and do this more often when kin or mates are present than other audience members.
So far, however, there has been no evidence that they take the other group members’ knowledge state into account.
Furthermore, to share new information with others by means of communication represents a crucial stage in the evolution of language.
This study thus suggests that this stage was already present when our common ancestor split off from chimps 6 million years ago.
The ability to recognize another individuals’ knowledge and beliefs may be unique to humankind.
For the finding, researchers from the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, and the University of St. Andrews, Great Britain, studied wild chimpanzees in Budongo Forest, Uganda.
They presented them with models of dangerous venomous snakes, two gaboon vipers and one rhinoceros viper.
“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”, said Catherine Crockford, a researcher at the University of St. Andrews.
The researchers have monitored the behaviour of 33 different chimpanzees, who saw one of three snake models and found that alarm calls were produced more when the caller was with group members who had either not seen the snake or had not been present when alarm calls were emitted.
“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 [the others] do not know about”, says Roman Wittig of the Max Planck Institute for Evolutionary Anthropology and the University of St. Andrews.
“In contrast, chimpanzees were less likely to inform audience members who already know about the danger,” he stated.
This study shows that these are not only intentionally produced alert calls, but that they are produced more when the audience is ignorant of the danger. (ANI)