Like Humans and Apes, Ravens Can Plan for the Future
The birds were able to choose and hold onto a tool that could unlock an eventual reward
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There’s no doubt that corvids—the family of birds that includes crows, ravens, jays and magpies—are smart. But as Ed Yong at The Atlantic reports , a new study on ravens shows just how intelligent the birds are. Researchers found they can actually delay gratification and plan for the future—a skill only previously documented great apes and in humans age four and older.
Lund University researcher Mathias Osvath raised five ravens for this study at his farm in Sweden. According to Yong, Osvath and his colleagues set up an experiment in which they trained the birds to open a puzzle box by dropping an oblong stone into a tube, which unlocked a box of tasty dog kibble. The researchers then moved the puzzle box out of the bird's sight. An hour later, they offered the birds a tray covered with enticing objects, including the stone that opens the puzzle box.
Though the birds had no knowledge of whether the kibble box would return or not, the ravens chose the box-unlocking stone from the tray in 86 percent of the tests. In a similar experiment, the birds exchanged a blue bottle cap for a treat. As Yong writes, "the cap had no intrinsic value and the birds" and they had no idea if the same researcher would return with food. But as with the case of the stone, in majority of the cases, the birds chose the tool that had a possibility of obtaining food in the future. They published their results in the journal Science.
“Say you’re planning a trip to London, and you know how often it rains there. So you bring an umbrella, even though it’s not raining now where you are. That’s what we are talking about here, planning based on past experience,” Osvath tells William Wan at The Washington Post.
In a separate experiment, Osvath tested delayed gratification. For the experiment, the ravens were trained to pick a token out of a group of objects, then hold onto the token for fifteen minutes before exchanging it for a treat, reports Anil Ananthaswamy at New Scientist. The ravens went for the token instead of a more immediate reward 77 percent of the time.
As Elizabeth Pennsi at Science reports, until about a decade ago, researchers believed humans were the only species that engaged in this type of planning. That is, until Osvath designed a test similar to the one he presented to the ravens to see if other primates are able to plan. While monkeys were unable to think too far into the future, great apes like chimps, bonobos and orangutans showed the ability to plan.
Over the last 20 years researchers studying corvids noticed signs that hinted the creatures might be able to plan as well. But not all were convinced, chalking up some of the evidence, like hiding food caches, to specialized behavior and not a general ability to think into the future.
So Osvath designed this most recent raven study to isolate planning behavior from such specialized behaviors by presenting the ravens with situations outside their normal life experience, like using a rock to open a box.
Still, not everyone believes the study shows that ravens are thinking into the future. “[I]t makes sense that the birds would develop a preference for that [stone] tool,” corvid researcher Jennifer Vonk at Oakland University who did not participate in the study, tells Yong. “It isn’t clear that this preferential selection reflects future planning.”
Osvath hopes to conduct more studies on the birds' cognitive abilities. But, as he tells Wan, these types of studies make some people uncomfortable since they blur the line between human and animal. “Yes, we humans are incredibly unique beings,” he says. “But if that’s all you focus on, you miss the wider question of cognition and its amazing place in nature."
Osvath says the true question behind studying cognition is: how do all living creatures go from an "accumulation of matter" to a thinking being. "That is one of the most astounding things in this universe,” he says.