by Whit Gibbons

October 8, 2006

Learning by experience is a natural trait of animals that have a brain. But the learning process has many aspects and is often a challenge for scientists to study. Recent research provided evidence that some nonhuman animals can plan for the future in a very deliberate manner.

Selecting an item in anticipation of using it later is something people do every day. Before you get in the car, you pick up the car keys. Before you leave the house, you grab your wallet or purse. Are any other animals able to deliberately select an item for future use? According to a series of experiments by Nicholas J. Mulcahy and Josep Call of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, the answer is yes. At least some animals other than humans can plan ahead.

Bonobos, or pygmy chimpanzees, are an endangered species native to the jungles of the Congo region of Africa. The species, one of a group of animals known as the great apes, has achieved a degree of notoriety because the DNA of bonobos has a 98 percent overlap in similarity to that of humans. This is scientific fact, so it should come as no surprise that these small chimpanzees have learning capabilities that exceed those of other nonhuman animals. Another of the great apes with cognitive learning abilities is the organgutan. Two species are found on the islands of Borneo and Sumatra. Colonies of bonobos and orangutans are kept in facilities at the Max Planck Institute for testing to learn more about the biology of these fascinating creatures.

Because the great apes are known for their intelligence, the researchers designed tests to see if bonobos and orangutans could learn to select and transport tools to be used at a later time. In other words, could they anticipate that a particular tool would be useful in the future, even though there was no use for it at the moment?

Bonobos and orangutans were led into a test room where they learned to use a plastic tool to dislodge a reward of fresh grapes. After the learning session, apes were taken to a waiting room with a window where they could watch as the scientists removed the tools but left intact the reward apparatus that held the grapes. Each ape being tested was kept in the waiting room for one hour and then led back into the test room, where it was unable to get the reward because the correct tool was no longer present. But before the ape was returned to the waiting room, several tools were placed in the test room. Some of tools were suitable for getting the grapes and some were unsuitable. The only way for an ape to get the reward of grapes on future trips to the test room was to pick up the proper tool when leaving, carry it to the waiting room, and then return with it to the test room.

Of three bonobos and three orangutans tested in the first experiment, all learned within seven trials to pick the correct tool and return with it to the test room. In 16 trials, one orangutan left and returned with the correct tool 15 times. The six experimental animals left the room with a tool 70 percent of the time, and the choice of a correct tool, compared to an inappropriate tool, was made a statistically significant proportion of the time. In another experiment, one of both species of test animals was placed in a waiting room for 14 hours between access to the tools and its return to the feeding apparatus. This means that they would have to select a tool and keep up with it for several hours before it would be useful.

Once again, the apes excelled. The two test animals successfully carried proper tools when they left the test room in 19 of 24 trials and returned with the correct tool 15 times. Demonstrably, apes can choose, keep, and return with a tool appropriate for future use. The researchers conclude that a propensity for planning for future needs evolved at least 14 million years ago, a time when chimpanzees and orangutans had a common ancestor.

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