When a person views a familiar image, even having seen it just once before for a few seconds, something unique happens in the human brain.
Until recently, neuroscientists believed that vigorous activity in a visual part of the brain called the inferotemporal (IT) cortex meant the person was looking at something novel, like the face of a stranger or a never-before-seen painting. Less IT cortex activity, on the other hand, indicated familiarity.
But something about that theory, called repetition suppression, didn’t hold up for University of Pennsylvania neuroscientist Nicole Rust. “Different images produce different amounts of activation even when they are all novel,” says Rust, an associate professor in the Department of Psychology. Beyond that, other factors — an image’s brightness, for instance, or its contrast — result in a similar effect.
In a paper published in the Proceedings…
