In a laboratory in Tübingen, two carrion crows faced a field of drifting dots and chose a side in less time than most of us need to blink twice. Their brains, built on a different plan from ours and lacking the layered cortex of mammals, seem to weigh the same kind of evidence that primates do, only faster. Such quickness is perhaps the old bargain of a flying, beak-guided creature, where seeing rightly and moving at once can mean survival. Why the crows' machinery arrives at this speed is still a question the study leaves open.
Crows Process Visual Decisions Twice as Fast as Humans and Monkeys, Tübingen Study Finds
Birds lack a layered cortex, yet decide twice as fast as primates
Mark
Start with the headline number. Crows decided in 235 milliseconds. What's that being compared to?
Mimi
Humans and monkeys doing similar visual decision tasks. The crows were about twice as fast, and they still got nearly 100 percent right when the dots moved clearly.
Luke
Before we get carried away: how many crows?
Mimi
Two carrion crows. That's a small sample, and it's worth keeping in mind.
Mark
And what did the brain recordings add?
Mimi
They looked at single neurons in the nidopallium caudolaterale, which does a job comparable to the prefrontal cortex. By 70 milliseconds after the dots appeared, neurons were already separating left from right.
Mark
So the brain was leaning before the bird moved.
Mimi
Yes, and activity kept rising until it reached a threshold tied to the decision. It reflected both how clear the motion was and which way the bird chose.
Luke
That fits the models used for primates, but it doesn't tell us why the crows are faster.
Mimi
Right. The researchers float the idea that flight and foraging demand quick vision and precise beak movements. That's their suggestion.
Luke
And the actual mechanism?
Mimi
Unknown. Nieder's team says more studies are needed to understand how a brain without layered cortex gets there so fast.
Le Pouls
- Two crows answered a moving-dot test in an average of 235 milliseconds, roughly twice the pace of humans and monkeys.
- Speed did not blur accuracy: the birds were nearly flawless on clear motion and still beat chance on murky motion.
- Neurons in the crow's nidopallium caudolaterale began splitting the two choices about 70 milliseconds after the dots appeared, long before any peck.
- The brain's decision signal rose steadily to a commitment threshold, matching models first built for primates despite a very different avian brain.
- The study rests on just two birds, and the biological mechanism behind the speed remains unexplained, so the puzzle is still wide open.
In a laboratory in Tübingen, two carrion crows faced a field of drifting dots and chose a side in less time than most of us need to blink twice. Their brains, built on a different plan from ours and lacking the layered cortex of mammals, seem to weigh the same kind of evidence that primates do, only faster. Such quickness is perhaps the old bargain of a flying, beak-guided creature, where seeing rightly and moving at once can mean survival. Why the crows' machinery arrives at this speed is still a question the study leaves open.
Two carrion crows sat before a touchscreen at the University of Tübingen, watching dots drift left or right. Their task was simple: decide the dominant direction and peck the matching side of the screen. On average, they took just 235 milliseconds, about twice as fast as humans and monkeys on comparable tasks, according to a study in Science led by Philipp Schmidbauer and Professor Andreas Nieder.
The speed did not cost them accuracy. With clear motion the crows were nearly perfect, and even when the dots were hard to read, they did better than guessing.
By recording individual neurons, the team found the birds' brains sorting the options remarkably early. About 70 milliseconds after the dots appeared, neurons linked to each choice were already firing in distinct patterns. Their activity then climbed toward a threshold for committing to a decision, tracking both the strength of the signal and the direction chosen.
This matters because the pattern resembles models of decision-making in humans and other primates, even though birds lack a layered cerebral cortex. The same basic principles for weighing evidence seem to operate in a differently built brain. Nieder suggests the speed may reflect evolution: birds rely on rapid vision for flight and for guiding their beaks while foraging.
Yet the researchers are careful. The explanation is a suggestion, the underlying mechanisms are unknown, and only two birds were studied. How such a differently organized brain reaches comparable visual decisions so quickly remains a question for future work.
Two carrion crows sat in front of a touchscreen at the University of Tübingen and watched a field of moving dots. Their job was to work out whether most of the dots were drifting left or right, then peck a target on the matching side of the screen. On average, they needed just 235 milliseconds to decide and respond.
That is about twice as fast as humans and monkeys manage on comparable visual decision tasks, according to a study published in the journal Science. The work comes from Philipp Schmidbauer and Professor Andreas Nieder of the university's Institute of Neurobiology.
Speed did not come at the cost of accuracy. When the dots moved with a clear direction, the crows reached nearly 100 percent accuracy. When the motion was hard to read, their choices were still better than chance. Schmidbauer put it that way: even with patterns that were difficult to recognize, the birds did better than random guessing.
To see what was happening inside the birds' heads, the team recorded the activity of individual neurons while the crows worked. They focused on a region called the nidopallium caudolaterale, which plays a role in processing information and making decisions, much as the prefrontal cortex does in humans.
The recordings showed the brain sorting out the two options very early. Only 70 milliseconds after the dots appeared, neurons tied to the different choices were already firing in distinct patterns, well before the birds moved to peck. From there, neural activity climbed steadily until it hit a threshold associated with committing to a decision. That activity tracked two things: how clearly the dots signaled a direction, and which direction the bird ended up choosing.
That pattern matters because it resembles the way decision-making is modeled in humans and other primates, even though bird brains are built differently. Birds lack a cerebral cortex organized in layers. Nieder said the findings show that neuronal dynamics in the avian brain are consistent with established models of decision-making in humans and non-human primates. In other words, the same basic principles for weighing evidence appear to operate in a differently structured brain, and in this task the crows ran through them twice as fast as primates.
The researchers suggest the speed may reflect evolutionary demands. Nieder explained that birds depend on vision for precise, rapid maneuvers in flight and for guiding their beaks to objects while foraging. Quick interpretation of what they see, followed by an accurate movement, is central to how flying, beak-using animals live.
The explanation is a suggestion, not a demonstrated cause. The exact biological mechanisms behind the crows' advantage remain unknown, and the study involved only two birds. Further research will have to determine how a brain organized so differently can reach comparable visual decisions so much faster than human and monkey brains do.
Citations marquantes
Neuronal dynamics in the avian brain are consistent with established models of decision-making in humans and non-human primates.— Andreas Nieder, University of Tübingen
Even when motion patterns were hard to recognize, the crows' decisions were still better than random, and with clear signals accuracy was nearly 100 percent.— Philipp Schmidbauer, University of Tübingen
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