Crows Outpace Monkeys in Decision Speed

Crows reach decisions twice as fast as monkeys while using the exact same underlying neural logic, according to a new study published today. This finding resolves a major question in neuroscience regarding how brains without a neocortex process complex choices. The results suggest that avian brains can achieve comparable decision-making efficiency through entirely different structural pathways.

Scientists have long relied on experiments where monkeys watch moving dots to understand brain function. In these trials, neurons in the primate neocortex collect visual evidence over time. Their activity levels rise until they hit a specific threshold, triggering a choice. Birds lack this specific brain region, which left researchers unsure how their minds handle similar cognitive tasks.

Andreas Nieder, a neurobiologist at the University of Tübingen, identified this gap as the central challenge of the study. He asked how a differently organized avian brain could encode decisions. To answer this, Nieder and his colleague Philipp Schmidbauer tested two hand-raised carrion crows. The birds sat in front of a touch-sensitive monitor displaying white dots on a black background.

The crows had to determine the direction of a drifting cloud of specks. They indicated their choice by pecking one of the targets next to the screen. A correct answer rewarded the bird with a mealworm. The researchers deliberately kept the setup identical to the monkey experiments. The only difference was the method of response, with crows pecking instead of making eye movements.

The team varied the difficulty of the task by changing the percentage of dots moving coherently. At the easiest level, 81 percent of the dots moved together, making the direction obvious. At the hardest level, only 3 percent moved in a coordinated way, creating a signal barely distinguishable from random noise. The researchers also included a condition with zero percent coherence, where no correct answer existed.

Despite the structural differences in their brains, the crows solved the task using the same mathematical logic as primates. This indicates that a brain without a neocortex can still arrive at decisions through a comparable accumulation process. The birds accomplished this feat at twice the speed of their primate counterparts, highlighting a significant advantage in processing efficiency for avian species.

The study underscores the flexibility of biological decision-making systems. It demonstrates that the specific architecture of the brain is less important than the underlying computational strategy. By matching the experimental conditions exactly, the researchers provided clear evidence that speed and accuracy in decision-making are not exclusive to primates. This work offers new insights into how different species process information under uncertainty.