Real Science

Thursday, 23 August 2007

Orangutans play charades

University of St Andrews, Scotland: Embargoed for release: 2-Aug-2007

Orangutans play charades

When orangutans make gestures to get their point across, they are using the same methods that people do when they play charades. Captive orangutans deliberately change or repeat signals depending on whether their audience 'got it' the first time.

The research is published in 2 August issue of the journal Current Biology.

The St Andrews University scientists were surprised that the orangutans were so clearly working out whether their audience understood what they were 'saying', says Professor Richard Byrne. “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."

This means that the great apes are passing information back to their audience about how well they have understood them, Byrne says. "Hence our charades analogy."

In playing the game of charades, we humans try to get our meaning across without words, using only gestures. And we also try to help our own team with hints about how they are doing - just as the orangutans have now been found to do.

The experiment that showed this was set up by Erica Cartmill and Richard Byrne. Their aim was to find out if orangutans intend to communicate with people through gesture. This is a skill that has already been found in chimpanzees.

The scientists presented six captive orangutans with two different food items. One was tasty to them. The other wasn't. Both could only be reached with human help.

There was another catch. The scientists sometimes pretended not to understand the orangutansrequests. So they would sometimes give them only half of the delicious treat. Or they would hand over the yuckier food instead.

When the human didn't get it right the orangutans kept trying to make them understand, the researchers report. When the humans seemed to partly understand, the animals narrowed down their range of signals.

They focused on gestures already used and they repeated them - just as humans do in charades. But when the humans seemed to completely misunderstand, the orangutans tried new gestures. They did not repeat the failed signals.

This showed that the orangutan intended a particular result, Cartmill says. "It anticipated getting it and kept trying until it got the result."

The orangutans made a clear distinction between total misunderstanding and partial misunderstanding, she says. In the first case they gave up on signals they'd used already. They tried new ones to get the message across. In the second case "they tended to repeat the signals that had already partially worked, keeping at it with vigour.

"The result is that understanding can be achieved more quickly.”

The charades strategy is one way to build a shared lexicon from learned signals, the researchers say.

So more study of how apes communicate could help us learn about how the earliest forms of human language began.

Cartmill et al.: “Orangutans Modify Their Gestural Signaling According to Their Audience’s Comprehension.” Publishing in Current Biology 17, 1–4, August 7, 2007 DOI 10.1016/j.cub.2007.06.069.

More help with words


great apes


What's it all about?

  1. What animal is this story about?
  2. Have the scientists been studying the animal in the wild?
  3. What word in the second sentence gave you the answer to the last question?
  4. At which university do the scientists work?
  5. Which country is this in?
  6. In the game of charades people don’t use words. Instead they try to get a message across to other people using --------.
  7. They also try to help their own team with ----- about how they are doing.
  8. The aim of the experiment was to find out if orangutans ------ to get messages across to people using gestures.
  9. This has already been found in another animal. Which one?
  10. Six orangutans were used in the experiment and two types of food. What was the main difference between the two types of food?
  11. Could the orangutans get the food by themselves?
  12. Somehow the orangutans had to make the humans ---------- them.
  13. Explain in one sentence why the humans pretended not to understand what the orangutans were trying to tell them.
  14. Give an example from the article of the humans partly understanding what the orangutans were trying to tell them.
  15. What did the orangutans do if the humans seemed to partly understand?
  16. If the humans seemed not to understand at all what did the orangutans do?
  17. Can humans tell the difference between being partly understood and not being understood at all?
  18. Do you think cats could? Or goldfish or canaries?
  19. What do you think this tells us about orangutans’ brains?
  20. Why might you expect to find a skill in orangutans that had already been found in chimpanzees?
  21. If you were these scientists can you think of one question you would still like to answer about how orangutans try to communicate?
  22. How could you try to answer that question?

More science teaching resources

Orangutans play charades UK US

Topic for discussion, research or pupil presentations

The following is extracted and adapted from a Discovery School lesson

Ask students to describe how apes, such as orangutans, chimpanzees and gorillas, are usually portrayed on TV or in the movies. Do they think the media portray the great apes realistically?

Rather than being cute, comical or dangerous, apes are highly intelligent – as this latest research clearly shows. They have been seen to use tools in thoughtful ways, exhibit self-awareness and demonstrate an empathic understanding of what other apes or humans are thinking and feeling.

Invite your students to imagine that they are working with the scientists at St Andrews. What kinds of experiments would they design in order to assess the thinking abilities of an orangutan?

Help students with their their ideas by asking what signs of intelligence they would look for.

Ask student working in groups to design four experiments: one that will assess an orangutan’s memory, one that will assess an orangutan's creativity, one that will assess an orangutan's ability to communicate, and one that will assess a factor that the students determine themselves.

Before they begin, review with them the requirements for a well-designed experiment, including the idea of a control group.

For each experiment that their groups devise, individual students should write one paragraph explaining what hypothesis it is designed to test and what results they expect to get from it.

When their work is complete, the teacher can conduct “scientific peer-review sessions” in which students review and critique each other’s experimental ideas.

Discussion Questions

1. Researchers are trying to learn how closely ape and human learning and behaviour resemble each other. One way is by teaching apes sign language. Even though these experiments don’t harm the apes, some people still object to this because the apes don’t get to choose whether or not to participate in the experiments. Debate whether animal experimentation of this kind is ethical

2. Apes can't speak because their vocal cords are different from those of humans. Since the 1940s scientists have been testing if meaningful communication between humans and apes is possible using a symbolic language. Their results have often seemed promising. One famous gorilla called Koko seems to have learned how to “speak” with American Sign Language. But some scientists have hotly disputed the results. Ask your students to use magazines, news reports and the Internet to research Koko’s sign language communications – what the scientists involved with the project claim to have discovered, and the criticisms of their methods and results. (A good place to start is

When their research is complete, ask them to write a set of questions whose answers could determine if Koko can actually understand sign language. Then divide students into pairs to critique each other’s experimental methods. Conclude with a class discussion about the questions the students developed and the difficulties in assessing Koko’s ability to communicate.

Suggested Reading

The Great Apes: Our Face in Nature’s Mirror. Michael Leach. Sterling Publishing, Inc., 1996. “Our closest living relatives are slowly being driven to extinction. Why? What can be done about it? As you read this poignant book, you’ll learn about the true nature of these animals as they live and behave in their natural habitat.”

Tips for science class discussions and groupwork

No 57

Marzano, in "Classroom Instruction that Works" notes that each time you set up the group, you need to remind them of the parameters, roles, etc. I have found that this is very true and when I do - even daily and occasionally within the class - remind them about how to work well in groups; I get much better results.

I find the most effective strategies for me are: a) make sure that everyone rotates through roles (even at high school level) and b) the group members get a stake in the evaluation process. Group grades and individual grades are important - I tell kids that I expect them to be honest, because if there is group work going on, then I am watching - and I will know it's wrong if the group that fought constantly gave themselves all A's (a rubric with a point system is better for evaluations - I like the way the one that someone posted for notebooks on the biology list is set up:

By the way - some good rubric examples on this site too; very impressive resource.

For some additional thoughts - check out: among others (Google

"Marzano cooperative learning").

Extract from a contribution to an online forum of the National Science Teachers Association by Kathleen M. Gorski, Ph.D., Kathleen M. Gorski, Ph.D., Master Teacher, The Nativity School of Worcester.


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