Monday, July 13, 2009
Face perception - the "Thacher Effect" in monkeys
Our talent for recognizing differences in faces relies on how facial features are configured. But, if the image of a face is flipped, alterations as drastic as inverted mouths and eyes aren't as noticeable — a phenomenon known as the Thatcher effect. Adachi et al. have monitored the length of time rhesus monkeys (Macaca mulatta) look at pictures of monkey faces. Over time, the animals become less interested in all images, but they spend significantly more time looking at the strange, upright altered (Thatcherized) photos than they do looking at the same images upside down. This suggests that perceptual mechanisms for individual recognition have been conserved through primate cognitive evolution.