When orangutans use gestures to get their point across, they rely on the same basic strategy that people follow in playing the game of charades, according to a new study appearing in todays issue of Current Biology.
Washington, Aug 2 : When orangutans use gestures to get their point across, they rely on the same basic strategy that people follow in playing the game of charades, according to a new study appearing in today's issue of Current Biology.
"We were surprised that the orangutans' responses so clearly signalled their assessment of the audience's comprehension. Looking at the tapes of the animal's responses, you can easily work out whether the orangutan thinks it has been fully, partially, or not understood--without seeing what went before," said Richard Byrne of The University of St. Andrews.
"This means that, in effect, they are passing information back to the audience about how well they are doing in understanding them--hence our 'charades' analogy. In playing the game, you want primarily to convey your meaning non-verbally--as does the orangutan--but secondarily to help the team get your meaning by giving them hints as to how well they are doing," he said.
To find out whether orangutans intentionally communicate with people through gestures-a skill earlier attributed to chimpanzees-Erica Cartmill and Byrne presented six captive orangutans with situations in which one tempting and one not-so-tempting food item had to be reached with human help.
But to test the orangutans' strategy, the researchers provided a catch. Rather than play along all the time, the experimenter sometimes purposefully misunderstood the orangutan's requests. In some cases, they provided only half of the delicious treat; in others, they handed over the yuckier alternative instead.
Findings revealed that when the person with whom they were trying to communicate did not meet the orangutans' aims, the apes persisted in further tries.
When partially understood, the animals narrowed down their range of signals by focusing on gestures already used and repeating them frequently. In contrast, when completely misunderstood, orangutans elaborated their range of gestures and avoided repetition of "failed" signals.
In other words, the orangutans' modified or repeated hand or other signals selectively based on the success or failure of their first attempt, the researchers said.
"The response showed that the orangutan had intended a particular result, anticipated getting it, and kept trying until it got the result The orangutans made a clear distinction between total misunderstanding, when they tended to give up on the signals they'd used already and use new, but equivalent, ones to get the idea across, and partial misunderstanding, when they tended to repeat the signals that had already partially worked, keeping at it with vigour," said Cartmill.
ANI