Crows outpace humans and monkeys in visual decision task
Two carrion crows responded in an average of 235 milliseconds, with accuracy approaching 100 percent when the visual signals were clear.
A University of Tübingen study found that two carrion crows could judge the direction of moving dots and signal their answer twice as quickly as humans and monkeys. The birds averaged 235 milliseconds per response while maintaining high accuracy, the researchers reported.
Philipp Schmidbauer and Professor Andreas Nieder, from the university's Institute of Neurobiology, tested the birds using a touchscreen. Each crow indicated whether most dots were moving left or right by pecking a target on that side. Their findings appeared in Science.
Performance exceeded chance even when the motion was difficult to distinguish, Schmidbauer reported. When the direction was clear, accuracy reached nearly 100 percent.
Recordings from individual neurons in the nidopallium caudolaterale, a brain region involved in decisions and information processing, revealed distinct activity for the two choices just 70 milliseconds after the dots appeared. Activity then built toward a decision threshold, reflecting both the clarity of the motion and the bird's eventual choice.
The researchers said these patterns fit established models of human and other primate decision-making, despite differences in brain organization. The biological mechanisms behind the crows' faster responses remain unknown.
