Lemmy and Iggy, two carrion crows, are no strangers to a psychology lab. As study participants, they have helped scientists prove that birds can use tools to forage, learn numbers and count objects, and provided other insights into the ways birds think.
Now, they’ve also revealed that birds can make staggeringly quick decisions, besting their human and nonhuman primate counterparts with ease. In new findings published in Science, the crows could process and respond to visual cues at twice the speed as humans and monkeys, quantifying the neural speed of avian decision-making for the first time.
The discovery might be the final blow for the use of “birdbrains” as a pejorative.
“We wouldn’t think of birds making these decisions faster than monkeys, or faster than us ‘awesome’ human beings,” said Mike Colombo, a neuroscientist and comparative psychologist at the University of Otago in New Zealand who was not involved in the research. “But they do. They’re just incredibly fast.”
Questions of bird intelligence have long been debated by researchers. Their small and superficially simple brains led scholars in the 19th and much of the 20th century to conclude they were not cognitively competent creatures. Even early research into birdsong, which demonstrated that some birds are capable of complex speech-like patterns and impressive vocal mimicry, was not enough to turn the tide. Their elaborate melodies were considered specialized adaptations that didn’t reflect their cognitive abilities.
Although passionate birders may find those conclusions obviously mistaken, the scientific community has been slower to catch on. “It’s taken the last 20 years to realize that actually their brain architecture is quite fascinating,” said Dr. Colombo.
Recent research, for example, has found that pigeons are capable of distinguishing between cancerous and noncancerous cells, numerical values, and words and non-words. Corvids (the group that includes crows, ravens, rooks and scrub jays) can even recognize themselves, solve abstract problems, plan for the future and show theory of mind — an ability to understand what other birds might be thinking and act accordingly.
For the new study, researchers at the University of Tübingen in Germany wanted to better understand how crows make decisions, so they set up an experiment to record their brain activity as the birds performed a visual task. After several weeks of training — and countless mealworm treats — Lemmy and Iggy learned to peck left or right to match the orientation of flashing white dots on a black screen.
During the experiment, the dots would randomly orient facing left or right. Sometimes a majority of the dots would align in one direction, making the task easy. Other times, only a small percentage would change, making it difficult. The crows’ objective was to peck the screen to match the orientation of the dots; at the same time, their neural activity was recorded by electrodes.
The researchers were particularly interested in the area of a bird’s brain called the nidopallium caudolaterale, which is comparable to the prefrontal cortex in primates. The prefrontal cortex is “the C.E.O. in our brain,” said Andreas Nieder, a neurophysiologist at the University of Tübingen and an author of the study. It’s responsible for many of our more cognitively complex abilities, including planning, working memory and abstract thinking. So activity in the comparable region might yield crucial insight into bird smarts.
The crows were allowed three seconds to make their decisions, but the results revealed they needed less than one. They reliably pecked their answers in about 235 milliseconds, which is twice as fast as rhesus monkeys or humans when performing similar experiments. Moreover, they pecked their decisions at breakneck speeds without compromising accuracy. “This was a result that we didn’t anticipate,” Dr. Nieder said.
To ensure the results weren’t a fluke, Dr. Nieder retested the crows and then turned to verify the methodology on every person he could get his hands on. “I think we tested all the people in my lab,” he said. But his undergraduate, Ph.D. and postdoctoral participants were no match for the crows.
The work underscores how the avian brain, despite its diminutive size, is tuned for rapid processing.
When comparing a crow’s nidopallium caudolaterale with a rhesus monkey’s prefrontal cortex, for instance, there are nearly the same number of neurons crammed into a smaller space. “So the bird brains are actually anatomically wired much more efficiently,” said Michael Griesser, a biologist and bird behavior expert at the University of Konstanz in Germany who was not involved with the research.
The Tübingen team suspects the ability to make such quick decisions might have evolved in response to the risky world of flight, where the difference between quickly or slowly reacting to something in the field of vision could be the difference between a smooth flight and crashing, or missing out on food.
Ultimately, the work is changing what it means to have a ‘birdbrain,’ or, as Dr. Colombo called it, an “incredibly efficient machine.”
