Sign up for CNN’s Wonder Theory science newsletter. Explore the universe with news of fascinating discoveries, scientific advances and more.
CNN
—
Maybe “Birdbrained” isn’t such an insult after all – crows, a ubiquitous urban bird, can count out loud to four, the latest research has found.
Not only can the curious creatures count, they can match the number of calls they make when shown numbers, according to a new study, led by a team of researchers at the Animal Physiology Laboratory of the University of Tübingen in Germany.
The way birds recognize and react to numbers is similar to the process we humans use, learning to count as young children and quickly recognizing the number of objects we are looking at. the findings, published Thursday in Science, we’ll deepen our growing understanding of crow intelligence.
“Humans do not have a monopoly on skills such as numerical reasoning, abstraction, tool making, and planning for the future,” animal cognition expert Heather Williams said via email. “No one should be surprised that crows are ‘smart.’” Williams, a biology professor at Williams College in Massachusetts, was not involved in the study.
In the animal kingdom, counting is not limited to crows. It was a chimpanzee Teaching counting in numerical order They understand the value of numbers, like young children. In an attempt to attract mates, some male frogs Count the number of calls from competing males To match or even increase this number when it is their turn to squawk at the female. Scientists even hypothesized that ants trace their paths to their colonies via… Count their stepsalthough the method is not always accurate.
What this latest study has shown is that crows, like young humans, can learn to associate numbers with values — and count out loud accordingly.
Lead study author Diana Liao, a neurobiologist and senior researcher at the Tübingen laboratory, said the research was inspired by young children learning to count. Young children use number words to count the number of objects in front of them: If they see three toys in front of them, their counting may sound like “one, two, three” or “one, one, one.”
Maybe crows could do the same thing, Liao thought. I was also inspired by a June 2005 study of chickadees that tailored their alarm calls to the size of the predator. The longer a predator’s wingspan or longer its body, the fewer “deep” sounds chickadees use in their alarm calls, according to the study. is found. The opposite was true for smaller predators, Liao said, with songbirds using more vocalizations if they encountered a smaller bird, which may pose a greater threat to chickadees because they are more agile.
The authors of the chickadee study could not confirm whether small songbirds control the number of sounds they make or whether the number of sounds is an involuntary response. But this possibility piqued Liao’s curiosity: Could crows, whose intelligence has been well documented over decades of research, demonstrate control over their ability to produce a certain number of sounds, and “count” as effectively as young children?
Liao and her colleagues trained three carrion crows, a European species closely related to the American crow, over more than 160 sessions. During training, the birds had to learn the associations between a series of visual and auditory cues from 1 to 4 and produce the corresponding number of cowls. In the example provided by the researchers, a visual cue might look like a bright blue number, and its corresponding sound could be a half-second song of drumming.
The crows were expected to perform the same number of caws as the number represented by the signal – three caws for the 3-numbered signal – within 10 seconds of seeing and hearing the signal. When the birds stop counting and squawking, they press the “enter” key on the touch screen displaying their signals to confirm that they have finished. If the birds count correctly, they will receive a reward.
It appears that as the signals continued, the crows took longer to respond to each signal. Their reaction times increased as more sounds approached, suggesting that the crows planned how many caws they would make before opening their beaks, Liao wrote.
The researchers were even able to tell how many calls the birds planned to make by the way their first call sounded — subtle acoustic differences that showed the crows knew how many numbers they were looking at and had accumulated the information.
“They understand abstract numbers… and then plan ahead when they match their behavior to match that number,” Williams said.
Even the mistakes made by the crows were fairly advanced: If the crows crowed too many times, stammered just as many times or gave their answers with their beak prematurely, Liao and her researchers could figure out where they had gone from the sound of the first call. mistake. These are “the same types of mistakes that humans make,” Williams said.
Birds and many other animals were previously thought to make instantaneous decisions only based on stimuli in their immediate environments, a theory popularized by 20th-century animal behaviorist B.F. Skinner. But the latest research by Liao and her colleagues provides more evidence about crows’ ability to group numbers to produce sound, and suggests that the skill is within their control.
The study team’s findings are very specific but still important, said Kevin McGowan, a researcher at the Cornell Laboratory of Ornithology in Ithaca, New York, who has spent more than 100,000 research studies. They challenge the common belief that all animals are simply stimulus-response machines. Over two decades studying wild crows in their habitats. McGowan was not involved in the study.
McGowan told CNN the study showed that “crows are not just simple, incapable of thinking machines interacting with their environment — they actually think ahead and have the ability to communicate in an organized, pre-planned way.” “It serves as a necessary introduction to having a language.”
Crow intelligence It has been studied for decades. Scientists have investigated New Caledonian crows Create their own composite instruments To access food. Birds seem to make the rules, according to A November 2013 study Co-authored by the principal investigator at the University of Tübingen laboratory, Andreas Nieder. Crow language has also confounded scientists for decades with its widely varying tones and expressions, McGowan said.
The study by Liao and her colleagues is not even the first to examine whether crows can count. Irene Pepperberg, an expert in animal cognition, notes that this research began with Nicholas Thompson in 1968. Pepperberg, a research professor of psychological and brain sciences at Boston University, is best known for her work with an African gray parrot named Alex.
Thompson hypothesized that crows could rely on their beaks, which birds seem to control the duration and number of a given burst of sound. He wrote that crows’ counting abilities “seem to exceed the requirements that survival would require for such abilities.”
Another university in Tübingen A study on crows’ counting abilities From September 2015, the researchers trained the birds to recognize groups of dots and recorded the activity of neurons in the part of crows’ brains that receives and understands visual stimuli. The researchers found that the crows’ neurons “ignore the size, shape, and arrangement of the dots and extract only their numbers,” the university reported. He said In a statement at the time.
“So, crows’ brains can represent different quantities, and crows can quickly learn to match Arabic numerals to those quantities — something humans usually teach their children explicitly,” Williams said.
“Beer aficionado. Gamer. Alcohol fanatic. Evil food trailblazer. Avid bacon maven.”