What does it feel like to feel up a robot? For most humans, it’s all well and good . . . until it’s not. At least, that’s what researchers from Stanford University found when they tested the physiological arousal of humans who touch robots in "private" places.

There has been plenty of research on what happens when robots and humans interact, but much of that work focuses on how it feels to talk to or be touched by a human-like machine. But Jamy Li, a PhD student in Stanford’s Department of Communication, wanted to know what happens when humans do the touching. So he programmed a small humanoid robot, recruited right-handed and left-handed students, and had them touch the robot in different places on its “body” under the guise of an anatomy lesson.

During the lesson, the robot asked its human counterparts to point at and touch different parts of its body. Participants wore a sensor that measured the electrical conductance of their skin. The research team then measured the electrodermal activity, or EDR, of the participants as they pointed to and touched 13 “body parts” of the robot, from its eyes to its buttocks and non-articulated genital area.

When humans’ emotions and attention are aroused, their sympathetic nervous system kicks in, filling their sweat ducts and increasing the conductance of the skin. That response was in full force during the study: When the 10 participants touched the robot rather than pointed at it, their physiological arousal rose. And for 90 percent of participants, arousal increased the more “off-limits” the body part got. Touching a robot's hand or neck elicited a less significant response than touching the eye or buttocks, for example.

In this case, "arousal" doesn't necessarily mean that the participants were having sexual thoughts about the robot. It just means that touching these intimate zones made them more alert. But whatever was making them more aroused when it came time to touch zones that might be off limits in other humans, they also seemed hesitant to do it – 80 percent of participants took longer to touch more "private" parts than ones commonly touched in human social interactions.

“There was a tendency to treat the robot like it had social rules that applied to it,” said Li, who will present his research at the 66th Annual Conference of the International Communication Association in June. “Perhaps people feel like robots with human-like bodies are more like a person.”

As humans interact with another physical “being” directly, Li said, they may be cued to adhere to social norms instead of treating the robot like a pile of metal, plastic and circuits. Maybe, he said, people even transfer their comfort levels with touching another human’s genitals or eyes — activities that are associated with intimate activity and close relationships — to robots that are in a more distant, teaching role.

Knowing that robots arouse physical reactions in humans, even in professional contexts, could help designers create machines that do a better job of making their human overlords comfortable. It could be that humans will always transfer the rules of human social interaction into their goings-on with robots, and that could dictate the way we use them. Although the study was too small to draw sweeping conclusions from, it helps researchers developing the next generation of robots for research and human assistance.

Li notes that after months of working with the robot, he doesn’t feel squeamish about touching it. That’s either a testament to the fact that feeling up robots is his norm . . . or an indication that time has broken down perceived social barriers between himself and the robots he studies.

Most of us don't interact often with humanoid robots. But there's an ongoing debate over the morality — and the potential emotional and biological consequences — of using robots for sex. When it comes to the use of robot touch for less-than-scientific purposes, Li is diplomatic. (His response to reports of a Hong Kong man’s freakily lifelike Scarlett Johansson robot replica? “That seems like a very specific type of robot.”) But he hopes that his research makes people think about what goes on when humans and robots connect. “It’s a powerful way to interact,” he said. “It makes us want to proceed with cautious optimism.”

42-year-old Ricky Ma made his own female robot modeled after Scarlett Johansson. (Reuters)

Erin Blakemore (@heroinebook) is a freelance journalist from Boulder, Colo. She is the author of "The Heroine’s Bookshelf" (Harper). 

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