Like chess players, these crows can plan several steps ahead
New Caledonian crows can use tools like sticks and stones, in a pre-planned fashion, to accomplish a goal.
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Crows are amongst the animal kingdom's smartest denizens.
Published 8 Feb 2019, 17:44 GMT, Updated 29 Nov 2021, 12:19 GMT
Planning ahead is actually more difficult than it seems. To do so, you have to fix in your mind a possible future, and then take concrete steps to make that scenario real. Even humans are rather notorious for a certain lack of planning.
The intelligence required to think well into the future is usually not attributed to animals. But new research shows that one type of crow can use tools to plan up to three moves ahead, to secure a meal—somewhat like a human playing chess, says Alex Taylor, a researcher at the University of Auckland in New Zealand.
The birds, known as New Caledonian crows, are famous for making tools, fashioning twigs into spears and hooks that they use to eat grubs. A member of the corvid family, they’re related to ravens, American crows, and magpies, and live in a group of islands east of Australia.
These crows are intelligent in many ways, capable of, for example, dropping rocks into a water-filled container to displace liquid and snag a floating bit of food.
But the degree to which they can mentally plot out actions ahead of time has been unclear, because such things are very difficult to definitively show, Taylor explains. (Related: Crows have human-like intelligence, author says.)
“It’s tricky to know how animals are thinking,” Taylor says. It’s easy to infer what’s going on, he says, but it takes precise testing to show—you cannot, unfortunately, just ask a crow what’s on its mind.
Taylor and colleagues created an experimental setup to do just that, which consisted of a box-like object in which different parts of a puzzle were hidden from the others. In one compartment, for example, they placed a twig. In another, a tube with a rock that could only be freed with the stick. In a third, a device dispensed a bit of meat when a rock was dropped in. A fourth area contained a distracting and unnecessary tool, either twig or rock.
The researchers familiarized and trained wild-caught birds to solve the separate tasks independently, so they for instance learned how to get food by dropping a rock into a chamber. After that, they set loose the birds on the four-part puzzle. (Related: Crows are better at tool-making than chimps.)
After hopping around and getting a lay of the land, many of the crows conducted the correct sequences of events to free the food without making any errors. The fact that these tasks were hidden from each other suggests that the crows were imaging in their minds the sequence necessary for getting the food.
“Picking the correct tool under a variety of scenarios for use somewhere else most likely means that the birds had a mental representation of that [place] and what was needed there to solve a complex task,” says John Marzluff, a researcher at the University of Washington and an expert on crows who wasn’t involved in the paper.
Marzluff concurs with the study, published February 7 in Current Biology, that it “provides the first conclusive evidence that birds can plan several moves ahead while using tools.”
The researchers also tweaked the tasks slightly to see if the crows were still capable of correctly planning and executing when circumstances changed, which many of them were. They found, perhaps unsurprisingly, that the animals were more adept at using twigs than rocks, which makes sense given their behavior in the wild.
The study raises tantalizing questions. Can other animals plan ahead, and to what degree of complexity? And what does this say about their intelligence and level of agency? (Learn why crows are among the smartest birds.)
For instance, the study shows that these birds, which have brains very different than those of great apes, nevertheless possess many similar mental abilities, says Kaeli Swift, a researcher at the University of Washington not involved in the study.
“Imagination is one of the cornerstones of the cognitive toolkit that we use to measure intelligence,” Swift says. “This shows strong evidence of such abilities in a bird.”
Studies of corvids keep showing that these animals high-order cognitive abilities—like planning and mental time-travel—to a degree that “we would have found laughable several decades ago,” she adds.
“It really goes to show how wrong we have been in using the term ‘bird brain’ as an insult and begs for our future dedication to these research questions.”