Princeton University researchers have come up with a new twist on the mysterious visual phenomenon experienced by humans known as the "uncanny valley." The scientists have found that monkeys sense it too.
The uncanny valley, a phrase coined by a Japanese researcher nearly three decades ago, describes that disquieting feeling that occurs when viewers look at representations designed to be as human-like as possible -- whether computer animations or androids -- but somehow fall short.
Movie-goers may not be familiar with the term, but they understand that it is far easier to love the out-of-proportion cartoon figures in the "The Incredibles," for example, than it is to embrace the more realistic-looking characters in "The Polar Express." Viewers, to many a Hollywood director's consternation, are emotionally unsettled by images of artificial humans that look both realistic and unrealistic at the same time.
In an attempt to add to the emerging scientific literature on the subject and answer deeper questions about the evolutionary basis of communication, Princeton University researchers have found that macaque monkeys also fall into the uncanny valley, exhibiting this reaction when looking at computer-generated images of monkeys that are close but less than perfect representations.
"Increased realism does not necessarily lead to increased acceptance," said Asif Ghazanfar, an assistant professor of psychology and the Princeton Neuroscience Institute, who led the research. It is the first such finding in any animal other than human. The paper, co-written by Shawn Steckenfinger, a research specialist in the Princeton's Department of Psychology, appears in the October Oct. 12 edition of the Proceedings of the National Academy of Sciences.
The work, according to its authors, is significant because it indicates that there is a biological basis for the uncanny valley and supports theories that propose that the brain mechanisms underlying the uncanny valley are evolutionary adaptations. "These data demonstrate that the uncanny valley effect is not unique to humans and that evolutionary hypotheses regarding its origins are tenable," said Ghazanfar.
The uncanny valley hypothesis was introduced by the Japanese roboticist Masahiro Mori in 1970. The "valley" refers to a dip in a graph that charts a human's positive reaction in response to an image on one axis and a robot's human-likeness on another. People like to study other human faces, and they also can enjoy scrutinizing countenances that clearly are not human, such as a doll's or a cartoon figure's. But when an image falls in between -- close to human but clearly not -- it causes a feeling of revulsion.
Experts praised the Princeton report.