Researchers at the University of Tübingen found that crows make visual decisions twice as quickly as humans and monkeys. In their experiment, two carrion crows needed only 235 milliseconds on average to spot the direction of a moving dot pattern and choose their answer, all while staying highly accurate.
Philipp Schmidbauer and Professor Andreas Nieder from the University of Tübingen’s Institute of Neurobiology showed that this quick decision-making is visible in the activity of crow brain neurons. Their study appeared in the journal Science.
In the experiment, the crows had to decide if moving dots on a touchscreen were mostly going left or right. They showed their choice by pecking at a target on the same side as the dots. “Even when the patterns of motion were hard to recognize, the crows’ decisions were still better than random choices,” Schmidbauer says. “And with clear signals, they achieved an accuracy of nearly 100%.”
To study this skill, the researchers measured neuron activity in the nidopallium caudolaterale, an important part of the crow brain similar to the human prefrontal cortex. Just 70 milliseconds after the visual cue started, the neurons began to show different signals for each motion direction, well before the crows responded.
Neural activity gradually increased as the decision was being formed, until it reached a decision threshold and the crow indicated its choice. The neurons reflected both the strength of the available visual information and the direction selected.
”These findings show that neuronal dynamics in the avian brain are consistent with established models of decision-making in humans and nonhuman primates,” says Nieder. Although birds lack a layered cerebral cortex, their differently organized brains appear to implement comparable basic principles of decision-making, and to do so twice as fast as primates.
Nieder explains that this speed may stem from birds’ evolutionary need for rapid visual processing and motor responses. “Birds rely on their vision to carry out precise, rapid maneuvers during flight and to guide their beaks toward objects when foraging,” he says. He adds that further research is needed to determine exactly which mechanisms enable this temporal advantage.
