Technology

Dancing robots reveal cultural cues

E-Puck robot
The way the robots learn dances has helped to understand cultural transmission

Viral videos, trending on Twitter, memes, fads and fashions. Human life is threaded through with information, images and ideas that we pass around.

Often though the mechanisms by which those briefly-shared obsessions travel can be hard to unravel.

Now dancing robots are helping to reveal some of the basic means by which those traditions, behaviours and ideas move, and mutate, in both human and animal societies.

The dancing robots were performing in a laboratory at the University of the West of England (UWE) as part of a long-term project that brought engineers, philosophers and cultural theorists together to analyse what the machines revealed.

"This was an extremely ambitious project," said Dr Alan Winfield, Hewlett-Packard professor of Electronic Engineering at the UWE who co-ordinated the research.

Copy bots

The robots used for the project were small, two-wheeled machines, called e-pucks, about the size of a tin of beans that were let loose in an arena to interact with each other. Every interaction was recorded with overhead video cameras.

Prior to being let loose, some of the robots had been programmed to perform different dances - essentially an intricate series of movements.

The researchers planned to find out how culture and shared behavioural traditions got passed on by studying how the robots told each other about these dances.

Robots which knew a dance were programmed to perform it in front of any robot they encountered while wandering the UWE arena.

The watching robot would then try to copy what it had seen.

Many ape groups have shared behaviours that newborns and newcomers must learn

Key to the project, said Dr Winfield, was giving the robots senses that share the shortcomings of animals and humans.

"One constraint in our system is that the robots can only see each other with their own senses," said Dr Winfield. In many other robot research projects, learned behaviours are passed from machine to machine by copying data. As a result, memories get passed on perfectly.

Not so in the UWE project, said Dr Winfield. The UWE robots had to watch what other robots did, work out how they performed the dance, and then try to copy them.

"The robots make copying errors for the same reasons that humans do," he said. "They are not perfect."

Variability was also introduced by the idiosyncrasies of each robot's construction, said Dr Winfield.

A stiff left wheel or underpowered motor would introduce a difference in the way that a robot performed a particular dance, he said. Robots watching would try to mimic this eccentricity even though it emerged by accident and that machine did not share the quirk of construction.

Stable culture

A lot of modern life is about sharing ideas, images and culture

By tracking how the dances were warped by the robot's fallible senses and physical differences it became possible to watch different interpretations ripple through the population of robots.

Re-running the experiment produced different dance variations and showed how small differences became amplified by repetition into much bigger changes.

"We've certainly demonstrated the emergence of stable behavioural types," said Dr Winfield.

"We found that they were doing the same things in a slightly different way," he said. "That's something that the primate zoologists would see among chimps."

This suggested, he said, that the robots were modelling the transmission of behaviour and culture, albeit in a much less sophisticated fashion than is seen among the Twitterati.

"This is a very simplified model and we are modelling only the smallest part of social learning and propagation," he said.

The next step is to make the robot society in the lab a little more realistic by introducing feedback so robots get to know how popular their dance has become.

One strange component of cultural transmission had been uncovered by the research, said Dr Winfield.

This component emerged from experiments with populations of robots that were given different amounts of memory. Three separate trials compared behavioural transmission among robots with almost no memory, infinite memory and a limited ability to remember.

"We got the largest number of stable clusters of dances in the robots with limited memory," said Dr Winfield. "That seems to suggest that forgetting has a valuable role in the emergence of stable shared behaviours."

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