Sign up for CNN’s Wonder Theory science newsletter. Explore the universe with news about fascinating discoveries, scientific breakthroughs and more.
Maybe “stupid” isn’t such an insult after all –– crows, the ubiquitous urban bird, can vocally count to four, the latest research finds.
Curious creatures can not only count, they can also match the number of calls they make when shown a number, according to a new study, led by a team of researchers from the animal physiology laboratory at the University of Tübingen in Germany. .
The way birds recognize and react to numbers is similar to a process we humans use, both to learn to count as children and to quickly recognize how many objects we are looking at. The evidence, Published Thursday in Science magazine, delve deeper into our growing understanding of crow intelligence.
“Humans do not have a monopoly on skills like numerical thinking, abstraction, tool making, and future planning,” said animal cognition expert Heather Williams in an 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. Chimpanzees were taught to count in numerical order and understand the value of numerals, just like children. In an attempt to court mates, some male frogs count the number of calls from male competitors to match or even surpass that number when it’s his turn to croak at a woman. Scientists have even theorized that ants retrace their paths back to their colonies, counting your stepsalthough the method is not always accurate.
What this latest study has shown is that crows, like young humans, can learn to associate numerals with values –– and count out loud accordingly.
Can crows count like little children?
The research was inspired by children learning to count, said study lead author Diana Liao, a neurobiologist and senior researcher at the Tübingen laboratory. Children use number words to count the number of objects in front of them: if they see three toys in front of them, the count might sound like “one, two, three” or “one, one, one.”
Maybe crows could do the same, Liao thought. She was also inspired by a June 2005 study about chickadees adapting their alarm calls to a predator’s size. The greater the wingspan or body length of a predator, the fewer “dee” sounds chickadees used in their alarm call, study says found. The opposite was true for smaller predators — songbirds would use more “dee” sounds if they encountered a smaller bird, which could be a greater threat to chickadees since they are more agile, Liao said.
The authors of the tit study were unable to confirm whether the small songbirds had control over the number of sounds they made or whether the number of sounds was an involuntary response. But the 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, effectively “counting” like young children do?
The crows planned their number of caws
Liao and his colleagues trained three carrion crows, a European species closely related to the American crow, in more than 160 sessions. During training, the birds had to learn associations between a series of visual and auditory signals from 1 to 4 and produce the corresponding number of quacks. In the example provided by the researchers, a visual cue might look like a bright blue numeral, and its corresponding audio might be the half-second music of a drum roll.
Crows were expected to perform the same number of caws as the number represented by the cue –– three caws for the cue with the numeral 3 –– within 10 seconds of seeing and hearing the cue. When the birds stopped counting and quacking, they would peck an “enter” key on the touchscreen that presented their cues to confirm they were finished. If the birds had counted correctly, they would receive a treat.
It seemed that as the signals continued, the crows took longer to react to each signal. Their reaction times increased as “more vocalizations were imminent,” Liao wrote, suggesting that the crows planned the number of caws they would make before opening their beaks.
The researchers could even tell how many calls the birds planned to make by how the first call sounded — subtle acoustic differences that showed the crows knew how many numbers they were looking at and synthesized the information.
“They understand abstract numbers… and then plan ahead as they adapt their behavior to that number,” Williams said.
Even the mistakes the crows made were somewhat advanced: If the crows cawed too many times, stuttered in the same number, or sent their beak responses prematurely, Liao and his researchers could detect from the sound of the first call where they went. wrong. These are “the same types of mistakes that humans make,” Williams said.
We’re Still Learning How Smart Crows Are
Previously, birds and many other animals were thought to make decisions only on the spot, based on stimuli in their immediate environments, a theory popularized by 20th-century animal behaviorist BF Skinner. But the latest research by Liao and his colleagues provides more evidence about crows’ ability to synthesize numbers to produce a sound and suggests that the ability is within their control.
The study team’s findings are highly specific but still significant — they challenge the once-common belief that all animals are just stimulus-response machines, said Kevin McGowan, a researcher at the Cornell Laboratory of Ornithology in Ithaca, New York. York, who has spent more than two decades studying wild crows in their habitats. McGowan was not involved in the study.
The study, McGowan told CNN, demonstrated that “ravens are not just simple non-thinking machines reacting to their environment – they are actually thinking about the future and have the ability to communicate in a structured, pre-planned way. It’s a kind of necessary precursor to having a language.”
Crow’s intelligence has been studied for decades. Scientists investigated New Caledonian crows creating your own composite tools to access food. Birds seem to set rules, according to one November 2013 Study co-authored with lead researcher at the University of Tübingen laboratory, Andreas Nieder. The Crow language has also confused scientists for decades, with its widely varying tones and expressions, McGowan said.
Liao and his colleagues’ study isn’t even the first to consider whether crows can count. This research began with Nicholas Thompson in 1968, noted animal cognition expert Irene Pepperberg. A research professor of psychological and brain sciences at Boston University, Pepperberg is best known for her work with an African gray parrot named Alex.
Thompson hypothesized that crows could count based on their caws, the duration and number of which the birds seemed to control in a given burst of sound. Crows’ counting capabilities “appear to exceed the demands that survival places on such capabilities,” he wrote.
Another University of Tübingen study on the counting skills of crows Starting in September 2015, he trained the birds to recognize clusters of dots and recorded the activity of neurons in the part of the crows’ brain that receives and makes sense of visual stimuli. The researchers found that the crows’ neurons “ignore the size, shape and arrangement of the dots and extract only their number,” the university said. he said in a statement at the time.
“Therefore, crows’ brains can represent different quantities, and crows can quickly learn to match Arabic numerals to these quantities — something humans often explicitly teach their children,” Williams said.
For more news and newsletters from CNN, create an account at CNN.com
