Carrion crows solve visual tests in half the time of monkeys
University of Tübingen researchers found that birds use the same mathematical logic as primates for decision-making but process the data at twice the speed.
By Giovanni Serrano ·
Crows make visual decisions twice as fast as monkeys while using the same underlying math.
Scientists have long relied on experiments with monkeys to understand how brains process information. These tests involve watching clouds of moving dots to determine direction. A new study from the University of Tübingen applied this specific task to birds for the first time.
Neurobiologist Andreas Nieder and colleague Philipp Schmidbauer tested two hand-raised carrion crows. The birds sat before a touch-sensitive monitor displaying white dots on a black background. A portion of the dots drifted in a specific direction. The crows indicated the direction by pecking a target, earning a mealworm for correct answers. The team varied the difficulty by changing the number of moving dots, ranging from 81 percent coherent movement to 3 percent.
The setup mirrored the standard primate test exactly. The only physical difference was the method of response. Monkeys indicated their choice through eye movements, while the crows used pecks. Nieder noted that the goal was to keep the conditions identical to isolate the brain's processing method.
The results showed that the crows used the same mathematical logic as primates. They accumulated visual evidence over time until their firing rates crossed a threshold. This confirms that a brain without a neocortex can handle similar decisions. The key difference was speed. The crows completed the task in half the time required by the monkeys.
This finding addresses a major question in neurobiology. Birds lack the neocortex found in mammals, which handles complex decision-making in primates. The study demonstrates that different brain architectures can arrive at the same logical conclusion. The avian brain encodes these decisions through a comparable process, just at a faster rate.
The research was conducted at the University of Tübingen. The team recorded brain activity while the crows performed the random-dot-motion task. The data supports the idea that decision-making logic is not strictly tied to one type of brain structure. The crows' performance offers a new benchmark for understanding visual processing in non-mammalian species.
Source: Ars Technica
