Humanoid robots have body shapes that are designed to resemble that of a human. On the surface, the expected human response to these robots is to view them as friendly, non-threatening computers.

However, a new study conducted by Stanford University found that humanoid robots could elicit an emotional response from humans.

In fact, touching humanoid robots in their intimate areas trigger feelings of arousal and discomfort. This discovery has several implications for the theory of artificial systems and robot design, experts said.

Touch As A Powerful Tool Of Communication

Previous studies have investigated gestures and speech as forms of interactions between humans and robots, but there is nothing quite as distinct and compelling as touch, researchers said.

"Our work shows that robots are a new form of media that is particularly powerful," said Stanford social scientist Jamy Li, lead author of the study. Touch is a great tool of communication that is understudied when it comes to human-robot interaction, he said.

Li explained that the typical notions we have of interacting through touch is by using touch screens, but it is different with humanoid robots. These robots' interfaces are bodies rather than flat panels.

In order to study the role of touch in robot-human interactions, the Stanford research team experimented with the NAO robot, a small humanoid from Aldebaran Robotics in France.

This tiny machine can recognize objects and faces, walk upright, understand and express emotions and react to touch and voice commands.

Li and her colleagues programmed the NAO robot to verbally instruct 10 study participants, who were fitted with an Affectiva-Q sensor on the finger of their non-dominant hands, to touch 13 parts of its body.

The sensors measured the electric conductivity of their skin, which reflected how much they were sweating. The sensors also assessed how long it took the participants to emotionally respond to the robot's instructions.

Researchers found that most of the participants were uncomfortable in touching the NAO robot's intimate parts, like the buttocks. One of the participants simply did not touch the robot at all in its intimate parts.

Li said there was heightened physiological arousal, meaning that the volunteers were more awake, more alert and paid more attention when asked to touch the intimate parts.

Implications Of The Study

The findings of the study suggest that people still interact with robots in a primitive way.

Li said that when a robot appears to look and talk like a person, people tend to treat it like a real person, even when they consciously know that it is a robot.

It also suggests that touch is a very compelling way in which people can interact with robots.

Meanwhile, Li said further studies can explore interactions with other kinds of robots, such as the ones that are not humanlike.

The team will present their study in Fukuoka, Japan at the International Communication Association conference on June 13.