The Raven: A Birdbrain Nevermore

Ravens’ performance in cognitive tests is on par with that of great apes.

Posted Dec 11, 2020

Yifei He, via Wikimedia Commons. Distributed under a CC BY-SA 4.0 license.
Common raven.
Source: Yifei He, via Wikimedia Commons. Distributed under a CC BY-SA 4.0 license.

By four months of age, the cognitive performance of ravens in experimental tasks testing their social intelligence and understanding of the physical world parallels that of adult great apes, according to a new study. The results indicate that not only do ravens possess sophisticated cognitive skills, but they also develop these skills rapidly.

“Even if you don’t know a lot about ravens or other corvids, their intelligence—and difference from most other bird species—becomes obvious when you observe them in the wild,” says Simone Pika, head of the Comparative BioCognition Group at the University of Osnabrück and co-author of the study.

Previous studies have demonstrated impressive cognitive abilities in ravens. These birds, members of the corvid family, are capable of forming coalitions, considering the visual perspective of others, planning for the future, and insightful problem-solving. Birds such as ravens have even been called “feathered apes” in recognition of their intelligence. But can they really compare with primates when it comes to higher cognition?

Georgine Szipl, used with permission.
A raven couple interacting.
Source: Georgine Szipl, used with permission.

To put this question to the test, Pika and colleagues adapted a battery of experimental tests designed for primates to meet the needs of ravens. This let them quantitatively compare the performances of ravens with those of chimpanzees and orangutans who had completed primate versions of the same tasks in a previous study.

The tasks include both physical and social cognitive skills. Physical cognitive skills include spatial memory, object permanence, understanding relative numbers and addition, and causal reasoning, while social cognitive skills include social learning, communication, and theory of mind.

Pika and colleagues conducted their cognitive tests with eight hand-raised ravens. The birds were tested at four, eight, 12, and 16 months of age.

The researchers found that, at four months old, ravens already possessed a full-blown set of cognitive skills. The ravens’ performances on physical and social cognitive tasks were impressive at age four months and did not significantly change over the time period investigated.

Comparing the cognitive performance of the ravens with chimpanzees and orangutans, Pika and colleagues found that, with the exception of spatial memory, the ravens’ performance was on par with that of the great apes.

Claudia Wascher, used with permission.
A raven on a perch.
Source: Claudia Wascher, used with permission.

The findings strengthen the idea that ravens, like great apes, have evolved general, flexible cognitive skills, rather than being highly specialized in a few domains only.

However, the researchers caution that the performance of these eight ravens may not be representative of the species as a whole. The birds in this study were tested by two highly familiar people who had hand-raised them. Such socialization factors could affect how the birds perform in cognitive tests designed and administered by humans.

Pika says that there is still much to learn about how ravens think. “I want to know more about the fast pace of ravens’ cognitive development, but also investigate possible cognitive changes after 16 months of age,” she says.

“Our ravens showed individual differences and differences between tasks, so I would also like to study how their personality affects performance and how socialization influences their cognitive development.”

It can be challenging to assess cognitive abilities in other species. This is compounded when the subjects are more evolutionarily distant from us, such as birds. This study is a first step in quantitatively measuring and comparing the cognitive abilities of different species. And although factors such as socialization and upbringing undoubtedly have an effect, the eight ravens in this study have shown they can pass our tests with flying colors.

References

Pika S, Sima MJ, Blum CR, Herrmann E, and Mundry R. 2020. Ravens parallel great apes in physical and social cognitive skills. Scientific Reports. Doi: 10.1038/s41598-020-77060-8.