Two crows decide twice as fast as humans
· BehindLines newsroom
Two carrion crows made visual decisions in 235 milliseconds on average, about twice as fast as humans and monkeys given the same test, according to a University of Tübingen (Germany) study published in the journal Science, which ScienceDaily and the New York Post report.
A test with moving dots
Researchers Philipp Schmidbauer and Andreas Nieder showed the birds dots moving across a touchscreen. The crows had to say whether most of them went left or right by pecking the target on the correct side. According to the New York Post, they were two males named Iggy and Lenny, rewarded with a mealworm, and it was the first time crows had taken this test.
Even when the motion was hard to make out, the choices stayed better than chance, Schmidbauer explains to ScienceDaily; with a clear signal, accuracy came close to 100%.
A brain without a layered cortex
The team recorded the activity of neurons in an area called the nidopallium caudolaterale, which for birds plays a role comparable to that of the prefrontal cortex in humans, according to ScienceDaily. Seventy milliseconds after the dots appeared, neurons associated with the two choices already showed different activity patterns, well before the physical response.
According to ScienceDaily, birds have no cortex organised in layers like mammals, and yet their decisions follow principles close to those of primates. For the New York Post, Nieder concludes that complex computation can be done without the neocortex found in mammals.
A speed that remains to be explained
The researchers suggest this quickness may reflect the demands of flight and foraging, where vision guides precise movements of the beak. The exact biological mechanisms remain unknown, however, and further studies will be needed, ScienceDaily says.
Why it matters
The experiment involved two birds, and the cause of their speed remains unknown, according to ScienceDaily. It nevertheless indicates, according to the authors, that brains organised very differently from ours can weigh visual cues by principles similar to those of humans and monkeys, but faster in this test.