Ravens Are Smarter Than Human Children

The way they plan for the future provides insight into the evolutionary history of intelligence.

Flickr / NatalieMaynor

It turns out that ravens are, in some ways, more intelligent that humans.

Research published Friday in Science made this claim based on studies following ravens not only collecting food with handmade tools like their crow brethren but also planning for their future and bartering for resources.

What astounded researchers was ravens’ ability to delay instant gratification. You may have seen a a cute video of tots recreating a classic psychology experiment where they can either eat a marshmallow right away or hold off for a few minutes and receive a second marshmallow as a reward. Most of them can’t help themselves. But ravens, a member of the corvid family of birds, succeed at a delayed gratification task 73 percent of the time.

“Even children — and sometimes adult humans — have self-control problems,” Can Kabadayi, the cognitive scientist from Sweden’s Lund University who ran the experiments, told Inverse. His paper, published Friday in Science, ran ravens through rigorous tests to figure out their cognitive capabilities.

“These kinds of tests require a host of cognitive skills that need to work in concert — that’s why it’s not easy for many animals,” says Kabadayi. He gives the example of great apes, who are adept tool users but often fail to plan for the future. “They can solve the problems if they see the tool and the problem at the same room. However, they fail if they have to ‘think ahead’ and prepare for a future event.”

Ravens were first required to use a tool to retrieve food from an otherwise inaccessible box. Then, after being presented with the box but not the tool, they needed to open it, ravens were presented with the tool but not the box, along with several other objects that wouldn’t open the box. Kabadayi reports that 86 percent of the time, ravens chose the correct tool so that they could extract their food the next time they were given a chance. In a final experiment, 76 percent of ravens were able to trade for the box-opening tool with a small token, and 73 percent chose to do so over taking a smaller reward that was readily available.

It’s like putting a treat on your dog’s nose and telling it to wait — except for ravens it doesn’t take any training.

“This is the key,” says Kabadayi. “You need to override immediate temptations that are available to you to attain a larger reward that is out of sight.”

By demonstrating their capacity for self-control, ravens have shown that they have comparable intelligence to great apes and people, even though they haven’t shared a common ancestor in 320 million years. Their advanced cognition evolved independently of ours and happened to end up the same. It is these roots and the evolution of animal cognition that Kabadayi hopes to uncover in his future work.

“[Birds and mammals] separated around 320 million years ago,” muses Kabadayi. “Independent run of life for 320 million years, and you reach similar ends, cognitively, using different neural substrates. Is this a recurring pattern in evolution? Can intelligence also converge? These are fascinating questions that drive me,” he said.

Right now, there is not much research into animal cognition because it’s difficult to create tests that will provide an accurate measure across species; measuring an animal that relies on vision’s ability to avoid transparent barriers won’t provide a useful comparison to a smell-dependent animal running the same course. However, when young ravens were compared to human children on an invisible barrier test, the ravens progressed much faster than the children did.

We also don’t know what part of the raven brain is responsible for their intelligent behavior, though Kabadayi speculates that the nidopallium caudolaterale might hold some answers. The nidopallium caudolaterale regulates self-control in the same way as a human’s prefrontal cortex. But again, the bird brain evolved independently of the mammalian brain, despite performing in the same way. Bird brains are more tightly-packed with neurons than mammal brains and ravens have the largest brains of all corvids, but no one has conducted definitive research to verify whether or not this is the source of their intelligence.

“It is still a small field,” says Kabadayi. “We need more species tested to understand how cognition evolves — to understand our place in nature, cognitively.”

Abstract: The ability to flexibly plan for events outside of the current sensory scope is at the core of being human and is crucial to our everyday lives and society. Studies on apes have shaped a belief that this ability evolved within the hominid lineage. Corvids, however, have shown evidence of planning their food hoarding, although this has been suggested to reflect a specific caching adaptation rather than domain-general planning. Here, we show that ravens plan for events unrelated to caching—tool-use and bartering—with delays of up to 17 hours, exert self-control, and consider temporal distance to future events. Their performance parallels that seen in apes and suggests that planning evolved independently in corvids, which opens new avenues for the study of cognitive evolution.
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