(Inside Science) -- Whether it’s an android, computer graphics in a movie, or a live Tupac hologram, animated representations of people can sometimes creep viewers out if the images don’t seem quite right. Now, new research suggests that monkeys may get creeped out by bad imitations, too.
Researchers have long noted that humans are more comfortable with things that look like people, but only to a certain point -- we sometimes have an aversion to things that are almost like us but a little off. Such an effect has been described as the “uncanny valley.”
One possible explanation is that an abnormal-looking human image may appear similar to a human with some sort of contagious disease -- something we have evolved to avoid. At the same time, we aren’t as averse to wholly unrealistic robots or holograms. It’s possible that we aren’t as worried about avoiding these unrealistic avatars since a disease would be less likely to spread from something that may not even be the same species, Siebert said.
The team found a similar effect with a type of monkey called the rhesus macaque. First, they created sophisticated images of monkeys using programs that tracked the movements and behavior of actual monkeys. They then played back videos of monkey avatars to live monkeys, using an eye-tracking program to see how much attention the monkeys paid to the videos.
The researchers played back avatars of four different qualities, ranging from realistic to basic outlines. They found that the macaques paid the most attention to actual videos of real monkeys as well as the most simplistic avatar, followed closely by the best avatar. However, the monkeys paid less attention to intermediate versions of the avatar that were done in grayscale or were otherwise lacking major features.
They also found that when presented with videos of real monkeys and the most realistic avatars, monkeys were more likely to perform a peaceful, affiliative gesture called lip-smacking. When presented with one of the intermediate-quality avatars, monkeys showed higher use of a the “fear grin,” a facial expression that signals fear. The researchers believe this shows that the avatars with a moderate level of detail fall into the uncanny valley, causing unease in their primate viewers. The study was published today in the journal eNeuro.
The researchers said this discovery provides evidence that the uncanny valley effect may have an ancient evolutionary origin, since monkeys apparently experience the same thing. They also believe this discovery may help researchers who study rhesus monkey behavior to design better experiments. Video avatars can be useful for evaluating how monkeys respond to different prompts, but the results could be skewed if the avatars are creeping the monkeys out.