Carrion crows make visual choices twice as quickly as primates
A University of Tübingen study finds that birds without a neocortex use the same evidence-accumulation logic as monkeys but reach decisions in half the time.
By Jason Kovalenko ·
Researchers at the University of Tübingen have demonstrated that carrion crows process visual motion at double the speed of primates while employing the same underlying decision-making logic. The finding challenges assumptions about how brains organized differently can handle complex sensory inputs.
The study, published on October 23, 2026, utilized the random-dot-motion task, a standard benchmark in neuroscience. In this test, subjects observe a cloud of flickering specks that drift weakly in a specific direction. The animal must determine the direction of movement. In primates, neurons in the neocortex accumulate visual evidence over time until their firing rates cross a threshold, triggering a choice.
Because birds lack a neocortex, scientists questioned how their brains encoded such decisions. Andreas Nieder, a neurobiologist at the University of Tübingen, described this as the central question of the research. "How [would] a differently organized avian brain encode decisions?" he asked. To answer, Nieder and colleague Philipp Schmidbauer tested two hand-raised carrion crows.
The crows viewed white dots on a black background on a touch-sensitive monitor. They indicated their choice by pecking targets flanking the display, earning a mealworm for correct answers. The researchers varied difficulty by adjusting the percentage of coherent dots, ranging from 81 percent, which was easily detectable, down to 3 percent, which was nearly indistinguishable from noise. A zero percent condition included no correct answer. Nieder noted the team kept the setup identical to monkey trials, with the only difference being the crows' pecking response versus primates' eye movements.
The results showed the crows solved the task using the same mathematical logic as primates, despite their distinct neural architecture. The birds reached their decisions in approximately 0.5 seconds, half the time required by monkeys in comparable tests. This speed advantage suggests that the absence of a neocortex does not preclude efficient, evidence-based decision-making.
