Teaching a Robot to Blink Could Get the World's Attention

Blinking is a small and often overlooked action in humans, but scientists believe that integrating this behavior into robots has great significance.

In a lab at the Italian Institute of Technology in Genoa, the BBC's Christine Ro sits across from a cute robot called iCub. Both of them hold sticks and tap a separate box in time to a flash of light.

'This is the first time I've played drums with a robot. I'm watching the robot and I know it's watching me ,' Ro told the BBC.

The drumming experiment was designed to test how having a robot perform the same task would affect human behavior. It is one of several experiments on human-robot interaction conducted by the CONTACT research group at the Italian Institute of Technology.

Ro's eyes were drawn to the iCub's heavy, white eyelids. She remembered the attention-getting noise the robot made every few seconds when it blinked. Because the iCub had large eyes, its gaze was captivating.

"Although blinking is often thought of as a physiological reflex related to eye protection and lubrication, it also plays an important role in interaction ," says Helena Kiilavuori, a psychology researcher at Tampere University in Finland.

Signal

According to the BBC writer, humans blink to convey attention and emotion. As a means of non-verbal communication, this action indicates a number of things that we are not consciously aware of, such as who should take over in a conversation.

Blinking is one of many social signals that humans constantly exchange without being consciously aware of it. As such, roboticists have studied both the physical and psychological properties of blinking behavior to understand why it might be useful to incorporate it into robots.

'Since blinking has many important functions in human behavior, it can be assumed that robot blinking would also significantly enhance the perception of similarity. This could facilitate human-robot interactions ,' said Kiilavuori.

iCub - robot of the CONTACT research group at the Italian Institute of Technology. (Photo: BBC).

Indeed, a study by the CONTACT team of 13-year-olds and adults in Italy, published in Research Gate, found that both groups preferred robots that blinked. Alessandra Sciutti, who led the study, points out that a robot that doesn't blink might make some people feel uncomfortable because of the stare.

People also think that the more naturally a robot blinks, the more intelligent it is. And intelligence is important in situations where humans rely on robots for information, such as in train stations.

But despite its many benefits, integrating natural blinking capabilities into robots is a technical challenge.

'Blinking is one of the most subtle human movements, so designing mechanisms that mimic this movement requires advanced technology, such as high-precision motors ,' explains Kiilavuori.

'For example, the robot builders at Engineered Arts use expensive, aerospace-grade motors, as well as design their own control electronics ,' she added.

"The speed at which the motor moves the skin material when blinking is really a challenge, " said David Hanson, founder of Hanson Robotics. "Making the shape of the eye look natural when blinking, while also reducing friction between the eyelid and the artificial eye surface, is also very difficult."

Another issue is the trade-off between motor speed and sound . According to Francesco Rea, a senior engineer on the CONTACT team, the iCub could use a quieter motor to reduce the sound of its blinking, but the slow speed makes the robot look sleepy.

Slow blinking also risks losing visual information because the iCub's camera is located behind the eyelid. "Missing two frames isn't a big deal, but missing 10 frames would be a problem ," Rea said.

Meanwhile, Ms Kiilavuori added , 'another challenge is the exact duration of blinking.' This action can change based on different emotional states, for example a person blinks faster or slower when lying.

'Any deviation in timing in a given context can make the robot look weird and unsettling,' she said.

Opportunity

At Disney Research, roboticists have collaborated with animators to develop a realistic robot gaze research prototype, with the aim of designing an eye-gaze expression system that would allow animators to easily control and convey subtle emotions.

With factors like eyelid movement curves, 'we can isolate these individual behaviors and focus on fixing small aspects and details,' says James Kennedy, a research scientist at Disney Research.

Getting robots to blink naturally like humans is a challenge. (Photo: BBC).

The Disney Research team has been granted a patent for a robotic gaze sensing and control system, which involves software that processes images captured by a camera in the robot's chest and generates control signals for movements such as opening and closing the eyelids.

The research is still experimental and has not yet been implemented in Disney theme parks, Mr Kennedy said. 'The goal is to take a single social cue and develop it as best as possible to create realistic movement and behavior, and then provide a platform for human interaction ,' he said.

But another common challenge is getting humanoid robots to synchronize their blink patterns with those of humans during conversations, a problem that remains a fascination for many robot builders.

According to the BBC, blinking is just one small example of many complex behaviors that make robot interactions seem unnatural, contrary to the exaggerated claims about the similarities between robots and humans.

When we try to recreate a mechanism as small and sometimes underappreciated as the blink of an eye, we really understand how complex and sophisticated it is. 'And that's a great opportunity for us to explore and invent ,' Mr Kennedy shared.