Why Are Humans Afraid to Touch Robot Butts?

A robot asks you to touch its butt.

Now, do you immediately go all-in on a game of robo grab-ass? There's nothing to feel weird about, after all, since a robot doesn't have, you know, feelings or an actual butt. It's just a hunk of vaguely anthropomorphic plastic and electronics. When humanoid robots are hanging around the office of the future, nobody should feel any stranger about touching one in the no-no zone than they would about touching the office printer… Right?

What I've just described is an actual experiment recently conducted by researchers at Stanford University, led by Jamy Li, and it has some perhaps confusing implications for how we see robots: merely as inhuman tools, or as something more?

"With people who own a Roomba, it's quite common that they'll give it a name or talk to it at home," said Li. "But it's also not a toaster. People don't usually pet their toasters. There might be a connection between touching the robot and intimacy. It goes beyond being a device."

As it turns out, human subjects felt pretty weird about being asked to touch a robot's private parts and then doing it, a variable measured in heightened skin conductance—when skin briefly becomes a better conductor of electricity—which researchers use as a proxy for physiological arousal. In total, participants were asked to touch 13 different body parts with varying levels of "accessibility." In humans, areas like the eyes, butt, and genitals are considered less accessible than, say, the hands.

"The finding that tactile sensation with a robot affects human physiology lends merit to the idea that robots can elicit powerful social responses from people," the researchers wrote. "These responses are not simply an act of playing along—they occur on a deeper physiological level." Their research will be presented at the Annual International Communication Association Conference in June.

The robot in question was an adorable little Nao model—the researchers say it resembles "a child or toy"—which makes the whole thing even more unsettling.

Although the team didn't evaluate why people appeared to react to touching a robot down there similarly to how we might expect them to react if they touched another human, they do suggest that the finding could be used to make better bots. A conversational robot that invites a touch on the shoulder and measures your physiological arousal may use that to gauge how you're feeling about the robot—how "close" you feel—and react accordingly.

Alternatively, we could just continue to be pervs to our little robot friends, in addition to kicking them around. You know, for science.