Crows decide in 235 milliseconds, twice as fast as humans and monkeys

A carrion crow watching a screen full of flickering dots can work out which way most of them are drifting and peck its answer in less than a quarter of a second. That is roughly twice as fast as monkeys and people have managed on the same kind of task, and the crows got there without sacrificing accuracy.

The finding matters because this dot test is the standard experiment of decision science, the one used for decades to show how a primate brain gathers evidence and commits to a choice. Neuroscientists at the University of Tübingen in Germany have now shown that a bird brain, built with none of the layered cortex that mammals rely on, solves the task with the same logic and gets to the answer first.

Philipp Schmidbauer and Andreas Nieder report in the journal Science that their two crows needed 235 milliseconds on average from the moment the dots appeared to the moment they began turning their heads to peck. In closely matched versions of the task, monkeys took roughly 410, 490 and 600 milliseconds across three earlier studies, and earlier work suggests human volunteers take about as long.

Inside the birds’ heads, the choice showed up even earlier. Neurons in a region called the nidopallium caudolaterale began to signal the direction a crow would pick about 70 milliseconds after the dots appeared, some 170 milliseconds before its head moved.

“We’ve never forced the crows to be as quick as possible,” Nieder told Ars Technica. “We just gave them a self-paced decision. And even in this situation, they were twice as fast compared to any monkey or human that I’m aware of.”

How two crows took a test built for monkeys

The two hand-raised crows sat in front of a touchscreen showing white dots on a black background. In each trial, a share of the dots moved together left or right while the rest wandered at random, and the bird reported the overall direction by pecking one of two targets beside the display. A correct answer earned a mealworm.

The researchers deliberately copied the monkey version of the experiment. “The only difference was that the crows had to peck to indicate their decision, whereas monkeys were indicating by making an eye movement,” Nieder said. To vary the difficulty, they changed the share of dots moving together from 81 percent, which is trivially easy, down to 3 percent, which is barely distinguishable from noise. Some trials had no coherent motion at all, so there was no right answer.

“Even when the patterns of motion were hard to recognize, the crows’ decisions were still better than random choices,” Schmidbauer said in the university’s announcement, “and with clear signals, they achieved an accuracy of nearly 100 percent.”

While the birds worked, the team recorded the activity of 248 individual neurons. Of those, 58 fired differently depending on which direction the crow would eventually choose. Their activity climbed gradually as evidence came in, scaled with how clear the motion was, and converged on a common level just as the bird committed to its peck.

The same rule, twice the speed

That rising pattern is what neuroscientists call a decision variable: a running tally of evidence that climbs until it crosses a threshold. Experiments led by Michael Shadlen and William Newsome made it famous in the parietal cortex of rhesus monkeys and the same random-dot task has since become a staple of human experiments too.

Birds and mammals went their separate evolutionary ways more than 300 million years ago. The mammalian cortex is stacked in sheets of cells, while the matching tissue in a bird is packed into dense clusters with no layers at all. Nieder’s team found that the bird version runs the same calculation. “These findings show that neuronal dynamics in the avian brain are consistent with established models of decision-making in humans and non-human primates,” Nieder said.

Evolution seems to have arrived at the same solution twice. “The bigger implication is that a brain does not need a mammalian neocortex to perform sophisticated computations,” Nieder told Live Science.

The time budget is the striking part. In primates, a hard version of the dot task can stretch a decision by hundreds of milliseconds. In the crows, reaction times ran from about 220 milliseconds on the easiest trials to 254 on the hardest, a spread of only 34 milliseconds. Nieder argues that the birds still accumulate evidence, since the drift of the dots was the only cue they had, but that every step runs so fast the slowdown nearly disappears.

Why a bird brain runs faster

The team cannot pin the speed on one process. Nieder suspects a chain of small advantages, from motion-sensitive bird vision through to the motor response, and points to two physical traits.

The first is size. Flight imposes strict weight limits, so birds pack enormous numbers of very small neurons into small brains, and the fibers that carry signals between them are short. “Long lines take time. Short lines speed everything up,” Nieder said. An earlier study in the journal PNAS found that songbird and parrot brains hold far more neurons per gram than primate brains do.

The second is heat. A human body sits at about 36.6 degrees Celsius, while birds run at 41 or even 42 degrees, and warmer tissue speeds up the chemistry of the nervous system. “Every ion channel would open and close faster. Every transmitter would move through the synaptic cleft faster,” Nieder said.

In the university’s announcement, he linked the advantage to how birds live. “Birds rely on their vision to carry out precise, rapid maneuvers during flight and to guide their beaks towards objects when foraging,” he said.

What the study does not settle

The study rests on two birds. That is a small sample, although Nieder notes it is the standard number for monkey experiments that combine behavior with recordings from single neurons.

The crows were not tested side by side with monkeys or people in the same lab. The comparison relies on published primate studies that used closely matched versions of the task, so small differences in equipment, response method and training could shift the gap. A peck and an eye movement are different actions, and the researchers timed the crows to the first movement of the head.

The numbers also belong to this task. The dot test asks a brain to wait for motion to reveal itself, so 235 milliseconds for crows and more than 400 for primates are not universal limits on how fast either can think.

Then there is the question of whether this is a bird trait or a crow trait. Corvids are among the most intelligent birds, and Nieder concedes that training a less clever species on the same task would be hard. “The problem with many other birds is that they are not as smart as corvids and crows and you need a smart bird in order to train it to do exactly this task,” he said. For now, nobody can say whether a pigeon would be as quick.

Common questions about how crows think

How fast can a crow make a decision?

In this experiment, carrion crows judged the main direction of a cloud of moving dots and began their response in about 235 milliseconds on average. Monkeys on matched versions of the task took roughly 410 to 600 milliseconds.

Are crows smarter than monkeys?

The study measures speed on one visual task, not overall intelligence. Crows matched primates for accuracy and beat them on time. Corvids are often called feathered apes because their problem-solving rivals that of primates, but a fast answer on one test does not rank whole species.

Do birds have a cerebral cortex?

Not a layered one. Birds lack the six-layered neocortex of mammals, but a region called the nidopallium caudolaterale does a similar job to the primate prefrontal cortex, using neurons arranged in clusters instead of sheets.

Why are bird brains so fast?

Nieder points to small, densely packed neurons with short connections and a body temperature several degrees above ours, which speeds up the chemistry of every nerve signal. The study did not test these explanations directly.

What comes next

Schmidbauer and Nieder published the work in Science on 22 October 2026, in volume 394 of the journal. Nieder has said further research is needed to determine exactly which mechanisms give birds their timing advantage. Rather than treating the mammalian brain as the blueprint for intelligence, he wants to compare species to find which computations all brains share and which are local adaptations, and a bird with a brain the size of a walnut has just shown why that comparison is worth making.

Reference: Schmidbauer P, Nieder A, “Ultrarapid decision-making in an avian brain,” Science 394, 445-449, 2026. DOI: 10.1126/science.aed6459

Tags: neuroscience, animal cognition, Andreas Nieder, bird brain, Corvus corone, crows