Robot touch makes people feel good

For many of us, the past two years have demonstrated how important the touch of others is to our emotional wellbeing — and how hard it is to go without it. But in the absence of physical contact from other humans, could robots provide an adequate substitute?  Past work has found that robotic touch can elicit positive emotions in people — and now a new study in Scientific Reports finds that the effect is better when the robots talk at the same time.

Taishi Sawabe from Nara Institute of Science and Technology and colleagues tested the effects of robotic touch and speech on 31 Japanese volunteers. In some trials, participants received gentle strokes on their back from a robotic arm. In others, they heard a synthesised voice saying phrases caregivers might use, such as "Hello. How are you doing? Did you sleep well last night?" or "Hello. Please take care of yourself. It has been chilly these days". And in a third kind of trial, they received the robotic touch and heard the robot speaking simultaneously.

After each trial, participants rated how positive or negative their mood was, as well as their emotional arousal (high arousal refers to feelings like excitement; low arousal to feelings like relaxation), and rated how human-like the robot was. The team also measured participants' muscle activity in the facial muscles involved in smiling, and recorded their skin conductance, a measure of physiological arousal.

Participants reported an overall positive mood on trials where the robot touched them, and on trials where it talked to them — but crucially their mood was significantly more positive on trials where it did both simultaneously. They also showed greater activity in the facial muscles associated with smiling on these combined trials. There were no differences in participants' feelings of arousal between trials, though they did have higher skin conductance on trials with both touch and speech than on trials with just speech. They also felt the robots were more human-like when they both talked and touched than when they just did one of these actions.

The findings could help to guide the design of robots made for people who suffer from a lack of human touch — elderly people living alone, for instance. More than a quarter of Japan's population is over 65 years old, and there are not enough care workers to meet the needs of the ageing population. Greater use of robots has been touted as one solution.

There are various limitations to the study, however. It's unclear whether an immediate boost in mood from an interaction with a robot translates to lasting effects, for instance, and whether personality or demographic differences could affect how people respond to the robots. And although it seems fairly uncontroversial to suggest that robots could be used to help with household tasks or medical care, there are practical and ethical questions about relying on machines to satisfy human psychological needs, particularly for people who are elderly or lonely. Still, if robots are to be commonplace in these kinds of settings, it'll be important to know how to make them most effective.  

Further reading

– Robot touch with speech boosts positive emotions

About the author

Matthew Warren (@MattBWarren) is Editor of BPS Research Digest