Next to humans, other species in the animal kingdom such as apes and monkeys have exhibited advanced relational thinking. But are there others? The newest species to join this list of highly intelligible animals? Crows.
Next to humans, other species in the animal kingdom such as apes and monkeys have exhibited advanced relational thinking. But are there others? The newest species to join this list of highly intelligible animals?
Crows.
Crows have long been known for their high intelligence. They have demonstrated the ability to distinguish different humans by remembering faces; some have learned to use bread crumbs for fishing; and they even have learned to use tools and store food across seasons.
To further back the crows' intelligence, a newly published study finds crows also have the brain power to solve higher-order, relational-matching tasks, and they can do so spontaneously.
“What the crows have done is a phenomenal feat,” says Ed Wasserman, a psychology professor at the University of Iowa and corresponding author of the study. “That’s the marvel of the results. It’s been done before with apes and monkeys, but now we’re dealing with a bird; but not just any bird, a bird with a brain as special to birds as the brain of an apes is special to mammals."
The study involved two hooded crows that were at least 2 years old. First, the birds were placed into a wire mesh cage into which a plastic tray containing three small cups was occasionally inserted. The cup in the middle was covered with a small card on which was pictured a color, shape or number of items. The other two cups were also covered with cards—one that matched the sample and one that did not. During this initial training period, the cup with the matching card contained two mealworms; the crows were rewarded with these food items when they chose the matching card.
Once the crows were trained to identity matching-to-sample, the researchers moved to the second phase of the experiment. This time, the birds were assessed with relational matching pairs of items. These relational matching trials were arranged in such a way that neither test pairs precisely matched the sample pair, thereby eliminating control by physical identity. For example, the crows might have to choose two same-sized circles rather than two different-sized circles when the sample card displayed two same-sized squares.
What surprised the researchers was not only that the crows could correctly perform the relational matches, but that they did so spontaneously—without explicit training.
“That is the crux of the discovery,” Wasserman says. “Honestly, if it was only by brute force that the crows showed this learning, then it would have been an impressive result. But this feat was spontaneous.”
Still the researchers acknowledge that the crows’ relational matching behavior did not come without some background knowledge.
“Crows Spontaneously Exhibit Analogical Reasoning,” was published Dec. 18 in Current Biology and is written by Wasserman and Anna Smirnova, Zoya Zorina and Tanya Obozova, researchers with the Department of Biology at Lomonosov Moscow State University in Moscow, Russia, where the study was conducted.
Read more at the University of Iowa.
Crow image via Shutterstock.
