Crows outpace primates in logic tests

Carrion crows make decisions using the same mathematical logic as primates, but they do it twice as fast.

Neurobiologists at the University of Tübingen recently completed a study comparing avian and primate cognition. For decades, the random-dot-motion task served as the primary method for understanding how brains process visual evidence. In this setup, a cloud of flickering specks drifts weakly in one direction. Subjects must identify the direction of movement to earn a reward. In primates, neurons in the neocortex collect this visual data over time. Their firing rates increase until they cross a threshold, prompting the animal to commit to a choice. Birds lack a neocortex, leaving open how their differently organized brains handle similar decisions. Andreas Nieder, a neurobiologist at the University of Tübingen, identified this gap as the central question of the work. He asked how a differently organized avian brain would encode decisions.

Nieder and colleague Philipp Schmidbauer tested two hand-raised carrion crows to close this gap. The researchers recorded brain activity while the birds worked through the task. The crows sat in front of a touch-sensitive monitor displaying white dots on a black background. A specific fraction of the dots drifted together to the left, right, up, or down. The birds reported the direction by pecking one of the targets flanking the display. A correct answer earned the crows a mealworm. Nieder stated that the team kept the setup identical to the monkey version to ensure a direct comparison. He noted that the only difference was the response method, with crows pecking to indicate their decision while monkeys used eye movements. The researchers varied the difficulty by changing how many dots moved together. At the easy end, 81 percent of the dots moved coherently. At the hardest end, only 3 percent did, making the signal barely distinguishable from noise. The team also included a zero percent condition with no correct answer.

The crows solved the task using the same mathematical logic as primates. Their brains arrived at decisions through a comparable process despite structural differences. The birds completed the task twice as fast as the monkeys. The next phase of the study will focus on further analyzing the specific neural pathways involved in this rapid processing. The team plans to publish the detailed neural data in the coming months. The findings confirm that a brain without a neocortex can utilize the same decision-making framework as primates.