Carrion Crows Solve Visual Tasks in Half the Time of Monkeys

Carrion crows complete complex visual decision tasks in half the time it takes monkeys, according to a study published on October 23. The findings demonstrate that avian brains achieve primate-like cognitive outcomes without possessing a neocortex.

The research team, led by neurobiologist Andreas Nieder and colleague Philipp Schmidbauer at the University of Tübingen, tested two hand-raised carrion crows. The birds performed a random-dot-motion task on a touch-sensitive monitor. White dots on a black background drifted in specific directions, and the crows indicated their choice by pecking a target. A correct response earned a mealworm.

In primate studies, neurons in the neocortex accumulate visual evidence until firing rates cross a threshold, triggering a decision. Because birds lack this brain region, scientists previously unclear how avian brains processed similar information. "This was the big question," Nieder said. "How [would] a differently organized avian brain encode decisions?"

The researchers designed the experiment to mirror monkey trials exactly. "We intentionally wanted to have exactly the same random-dot motion task," Nieder noted. The only operational difference was the output method. Crows pecked to respond, while monkeys used eye movements. This controlled comparison allowed for a direct speed assessment between the two species.

Difficulty levels ranged from 81 percent coherent motion, which is easily detected, down to 3 percent, which is nearly indistinguishable from noise. The team also included a zero percent condition with no correct answer. Across these varying levels, the crows applied the same mathematical logic as primates to resolve the ambiguity.

The data shows that the crows reached their decision threshold twice as fast as the monkey subjects. This speed advantage persists despite the fundamental structural differences in their brains. The study confirms that a neocortex is not required to perform high-speed visual decision making.

The results provide concrete evidence that different brain architectures can solve the same computational problems. By matching primate accuracy while doubling the processing speed, carrion crows offer a new model for understanding cognitive efficiency in non-mammalian species.