Apparently, keeping an eye on a real impala is easier than focusing on a Chevy Impala. Because monitoring predators, prey and people was a life-or-death matter for humans during evolution, researchers investigated whether people were more likely to pay greater attention to animals than to anything else. The scientists rapidly flashed photographs of natural scenes at volunteers. These pictures were shown in pairs that were identical, save for a change to a single object. The volunteers proved substantially faster and more accurate at detecting alterations involving animals—including other humans—than inanimate objects, even if the animals were small, peripheral and blended into the background. This result even proved true with vehicles, which the volunteers had presumably spent years watching for life-threatening changes in trajectory. Visual priorities of our hunter-gatherer ancestors evidently remain embedded in the modern brain, regardless of how relatively useless they often are now, the scientists reported online September 24 in the Proceedings of the National Academy of Sciences USA.
This article was originally published with the title "Eye on the Tiger" in Scientific American 297, 6, 37 (December 2007)