Crows Can Evaluate Visual Info Twice As Fast As Mammals (arstechnica.com) 1
Researchers at the University of Tubingen found that crows can process visual information and make decisions roughly twice as fast as monkeys or humans without sacrificing accuracy. They suspect birds' densely packed neurons and higher body temperatures contribute to their faster processing, though the study involved only two crows. Ars Technica reports: [Andreas Nieder, a neurobiologist at the University of Tubingen and his colleague Philipp Schmidbauer] put two hand-raised crows in front of a touch-sensitive monitor showing a cloud of white dots on black, with some fraction of them drifting coherently left or right or up or down. The birds' job was to report the overall direction by pecking one of the targets that flanked the display. Correct answers earned them a mealworm. "We intentionally wanted to have exactly the same random-dot motion task," Nieder said. "The only difference was that the crows had to peck to indicate their decision, whereas monkeys were indicating by making an eye movement."
The researchers varied how many dots moved together, ranging from 81 percent of the dots coherently moving together, which is trivially easy to determine, down to 3 percent, which is barely distinguishable from noise. They also included a zero percent condition, in which there was no correct answer. Both birds scored better than chance, even when only three percent of the dots were moving. While the crows worked at the task, the team recorded from 248 neurons in the NCL (nidopallium caudolaterale) -- a region at the top of the avian processing hierarchy that is widely regarded as the functional counterpart of the primate prefrontal cortex, despite being built differently.
Birds and mammals parted evolutionary ways more than 360 million years ago, and bird brains evolved a different architecture. The mammalian cortex is arranged as stacked sheets of cells, while the equivalent tissue in a bird is organized into dense clusters, with no layering at all. This alternative architecture, Nieder's study found, proved faster. Measured from the moment that the dots appeared to the moment the bird's head started turning to peck at the button, the crows averaged 235 milliseconds. In closely matched versions of the task, monkeys took roughly 410, 490, and 600 milliseconds in three studies. The obvious question was whether the birds simply sacrificed accuracy for speed, but it turned out they did not. The research has been published in the journal Science.
The researchers varied how many dots moved together, ranging from 81 percent of the dots coherently moving together, which is trivially easy to determine, down to 3 percent, which is barely distinguishable from noise. They also included a zero percent condition, in which there was no correct answer. Both birds scored better than chance, even when only three percent of the dots were moving. While the crows worked at the task, the team recorded from 248 neurons in the NCL (nidopallium caudolaterale) -- a region at the top of the avian processing hierarchy that is widely regarded as the functional counterpart of the primate prefrontal cortex, despite being built differently.
Birds and mammals parted evolutionary ways more than 360 million years ago, and bird brains evolved a different architecture. The mammalian cortex is arranged as stacked sheets of cells, while the equivalent tissue in a bird is organized into dense clusters, with no layering at all. This alternative architecture, Nieder's study found, proved faster. Measured from the moment that the dots appeared to the moment the bird's head started turning to peck at the button, the crows averaged 235 milliseconds. In closely matched versions of the task, monkeys took roughly 410, 490, and 600 milliseconds in three studies. The obvious question was whether the birds simply sacrificed accuracy for speed, but it turned out they did not. The research has been published in the journal Science.