In a quiet laboratory in Tübingen, two carrion crows watched fields of drifting dots and chose a direction in roughly a quarter of a second, faster than humans or monkeys manage the same task. The finding, reported in Science by researchers at the university's neurobiology institute, reminds us that a mind need not look like ours to weigh evidence and commit to a choice in much the same way. Their brains, built without a layered cortex, appear to follow the same basic arc of gathering signals until a threshold is crossed. Why these birds should be so quick is still an open question, though the
Carrion Crows Make Visual Decisions in 235 Milliseconds, Twice as Fast as Humans and Monkeys
Seventy milliseconds in, the crow's neurons had already begun to take sides.
Mark
So what did the crows actually do?
Mimi
They watched moving dots on a touchscreen, decided whether most were going left or right, and pecked the matching side. The average was 235 milliseconds.
Mark
And that's twice as fast as people?
Mimi
Twice as fast as humans and monkeys, according to the researchers, and still close to 100 percent accurate on clear signals.
Luke
Worth saying plainly: only two crows were tested. The speed result is striking, but it's a small sample.
Mark
What about the brain recordings?
Mimi
In the nidopallium caudolaterale, neurons were separating the two choices by 70 milliseconds after the dots appeared, well before the peck.
Mark
Why does that region matter?
Mimi
It does a job comparable to the prefrontal cortex in humans, even though bird brains lack a layered cortex. The activity built up to a threshold, like decision models in primates.
Luke
The evolutionary explanation, flight and foraging, is the researchers' suggestion. It isn't demonstrated here.
Mark
So what's still missing?
Mimi
The mechanism. Nobody yet knows how a differently built brain gets there so much faster.
Luke
Right, and that's the honest edge of the story.
Le Pouls
- Two crows, a touchscreen, and a field of moving dots turned a routine perception test into a challenge to what we thought we knew about speed of thought.
- Decisions landed in about 235 milliseconds, roughly twice as fast as humans and monkeys, and the researchers had to ask whether that speed came at a price.
- Neurons in the crow's nidopallium caudolaterale began sorting the two choices within 70 milliseconds, long before any movement was made.
- The scientists are now chasing the biological mechanism behind the advantage, with only two birds in the study and many questions still unanswered.
In a quiet laboratory in Tübingen, two carrion crows watched fields of drifting dots and chose a direction in roughly a quarter of a second, faster than humans or monkeys manage the same task. The finding, reported in Science by researchers at the university's neurobiology institute, reminds us that a mind need not look like ours to weigh evidence and commit to a choice in much the same way. Their brains, built without a layered cortex, appear to follow the same basic arc of gathering signals until a threshold is crossed. Why these birds should be so quick is still an open question, though the researchers point toward a life lived by sight, in flight and in foraging.
Two carrion crows sat before a touchscreen at the University of Tübingen, watching dots drift left or right. Their job was to decide the direction and peck the matching side of the screen. On average, each bird made the call and responded in just 235 milliseconds.
The result, published in the journal Science by Philipp Schmidbauer and Professor Andreas Nieder, suggests crows reach visual decisions about twice as fast as humans and monkeys. Speed did not cost accuracy. When the motion was clear, the crows were nearly flawless, and even when it was hard to read, they still beat chance. Only two birds took part, a small group that the team nonetheless studied closely.
Inside the birds, the researchers recorded individual neurons in a region that, in birds, plays a role similar to the prefrontal cortex in people. Activity sorted the two choices about 70 milliseconds after the dots appeared, and it climbed steadily toward a threshold before the bird committed. That climb tracked both how clear the signal was and which way the bird chose.
The pattern is striking because crow brains lack a layered cerebral cortex, yet they seem to follow the same logic of gathering evidence until a decision is reached. Nieder said the findings fit established models of decision-making in humans and primates. The reason for the speed remains unknown, though the team suggests evolution may have favored rapid vision for flight and for guiding beaks while foraging. Further studies are needed to explain how such differently built brains reach comparable decisions so much faster.
Two carrion crows sat in front of a touchscreen at the University of Tübingen, watching a field of moving dots. Their task was to decide whether most of the dots were drifting left or right, then peck a target on the matching side of the screen. On average, it took each bird just 235 milliseconds to make the call and respond.
That speed is the headline of a study published in the journal Science, led by Philipp Schmidbauer and Professor Andreas Nieder of the university's Institute of Neurobiology. By their account, the crows reach visual decisions about twice as fast as humans and monkeys do on comparable tasks. Only two birds took part in the experiments.
Speed did not come at the cost of accuracy. When the dots moved with a clear direction, the crows scored nearly 100 percent. Even when the motion was hard to read, their choices were still better than chance. Schmidbauer put it this way: the decisions held up above random guessing in difficult conditions, and with clear signals the birds were almost never wrong.
The team also wanted to know what was happening inside the birds' heads while they worked. They recorded the activity of individual neurons in a region called the nidopallium caudolaterale, which plays a role in processing information and making decisions, much as the prefrontal cortex does in people.
The recordings showed the brain getting to work almost immediately. Just 70 milliseconds after the dots appeared, neurons tied to the two possible choices were already firing in distinct patterns. These signals came well before the birds moved. As the crows weighed the dots, neural activity climbed steadily until it hit a threshold associated with committing to a decision. The activity tracked both how clearly the dots signaled a direction and which way the bird ended up choosing.
That pattern matters because crow brains are built differently from those of primates. Birds lack a cerebral cortex organized into layers, yet their neurons appear to follow the same basic logic of gathering evidence and reaching a threshold. 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.
Why the crows are so much faster is not settled. The researchers suggest it may reflect evolutionary pressures: birds depend on vision for precise, rapid maneuvers in flight and for guiding their beaks toward objects when foraging. Nieder explained it in just those terms.
The exact biological mechanisms behind the speed advantage remain unknown. Further studies will be needed to work out how a differently structured brain can arrive at comparable visual decisions so much faster than human and monkey brains.
Citations marquantes
The findings show that 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 with hard-to-read motion the crows beat chance, and with clear signals they reached nearly 100 percent accuracy.— Philipp Schmidbauer (paraphrased)
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