Crows make faster better decisions in screen test
Two carrion crows chose the direction of moving dots in an average of about 235 milliseconds, while maintaining accuracy when the patterns were clear…
Two carrion crows made faster choices than humans in a screen-based test, averaging about 235 milliseconds per decision, researchers found. The crows also chose correctly 100% of the time when the movement patterns were clear.
The result offers a look at how birds make rapid decisions without a mammalian neocortex. Researchers tested two male carrion crows, Iggy and Lenny, using moving dots on a touch monitor.
How did the crows make their choices?
The screen showed clusters of dots. Some moved left or right, while other dots shifted randomly as distractions. The crows pecked the corresponding side of the monitor to identify the direction of the target movement.
A correct choice earned a mealworm. Before researchers collected data, the birds completed the tasks thousands of times, helping establish accuracy across repeated trials.
Humans and monkeys had previously taken similar dot tests, but the researchers said this was the first time crows had been tested in this way. The birds’ average decision time was roughly twice as fast as the times recorded for their human and simian counterparts.
Fast, accurate choices matter because the same abilities can support visual processing and motor responses during flight, beak movements and predator evasion, the experts said. The test, however, measured responses to controlled visual patterns rather than every kind of decision a crow makes in the wild.
What did researchers record in the birds’ brains?
Researchers implanted electrodes to record activity from 248 neurons in the nidopallium caudolaterale, or NCL. The region performs roughly the same function in birds as the prefrontal cortex does in primates.
By tracking that activity, the team could predict a crow’s eventual choice 70 milliseconds after the dots appeared—roughly 170 milliseconds before the bird selected a side. The measurements linked neural activity to the decision while the visual task was underway.
Study co-author Andreas Nieder, an animal physiologist at the University of Tübingen in Germany, said the findings point to decision-making abilities similar to those of primates. “The bigger implication is that a brain does not need a mammalian neocortex to perform sophisticated computations,” Nieder said.
The results put pressure on the assumption that sophisticated computation depends on the brain structure found in mammals. In this experiment, the crows combined speed with accuracy when the motion was clear, and researchers could identify the direction of their choice before they pecked the screen.
The birds averaged approximately 235 milliseconds for each choice.
