Infants show greater unease towards computer-morphed faces when shown ‘half-mother’ images

When interacting with robots or animations with unnatural-looking faces, many people report a sense of unease. The face seems familiar yet alien, leaving the brain uncertain whether it is definitely human. To make robots more acceptable, it is necessary to understand the roots of these emotional reactions. Research from Japan has now shown that these reactions may begin in early infancy.

Yoshi-Taka Matsuda and colleagues at the Japan Science and Technology Agency, Saitama, and the RIKEN Brain Science Institute, Wako, together with scientists from The University of Tokyo and Kyoto University, studied the reactions of infants to computer-morphed photographs of faces. They showed that this unease, known as the uncanny valley effect, may begin as young as nine months, but only when the morphed image is partly developed from photographs of a familiar person—in this case, their mother. “Infants like both familiarity and novelty in objects,” explains Matsuda. “We wondered how their preference might change when they encountered objects that are intermediate between familiarity and novelty.”

The researchers used an eye-tracking system to record where and for how long the infants viewed the images. They found that the infants preferred looking at the photos of their mothers than the ‘half-mother’ morphed faces, but there was no significant difference between the times they spent looking at real and morphed photos of strangers.