Science has been telling us about how intelligent ravens are for years. They can feel paranoid. They're at least as smart as chimps and they can recognize cheaters. A new study, published this month in the journal Science, shows ravens can keep an eye on the future by planning ahead, bartering and exhibiting self-control on par with apes and small children.
The study used feathered test subjects in a series of experiments. It started with training ravens to use a tool to open a puzzle box. Open the box, get a reward. Then, the researchers gave the ravens the box, but not the tool. After an hour, the researchers took the box away and gave the raven the tool along with several other items that were not the tool. "Nearly every raven chose the correct, apparatus-opening tool; Upon being presented with the box 15 minutes later, they used the tool to open it, with a success rate of 86 percent," the researchers note.
When given the choice between a less-desirable immediate food reward, a variety of unrelated items and the box-opening tool (with the box being withheld until later), the ravens chose to take the tool and wait for the premium reward. That's more self control than a lot of humans have. The prized food reward was a piece of dog food.
The scientists also worked with ravens on a bartering system where the birds were asked to exchange a token (a blue plastic bottle cap) for a food reward.
The small study group included five adult ravens, three females and two males. The birds were all hand-raised at the Lund University Corvid Cognition Station in Sweden.
"All subjects participated in testing on a voluntary basis, such that they could choose to come to the experimental compartments when called upon, and could choose whether to interact with the experimenters and the materials; any signs of distress would have caused the testing session to be terminated," the researchers note.
The researchers say the ravens' ability to barter and to plan ahead for their use of tools is similar to that seen in studies of apes. These are also very familiar human behaviors. The ravens' and apes' skills may parallel each other, but they evolved independently.
"The conspicuous similarities in performance to great apes in tasks such as these opens up avenues for investigation into the evolutionary principles of cognition and shows what the brains of some birds are capable of," the study concludes.
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