Artificially evolving social robots

Carl Zimmer has written a fascinating piece on a study that simulated the evolution of communication in artificially intelligent robots.

The robots were small and mobile, were controlled by artificial neural networks, and could send and receive signals via infrared.

A group of robots was put into an arena with a light-emitting ‘food source’ and a ‘poison source’. The robots could only tell the difference when they got close enough to see coloured paper that the ‘sources’ were resting on.

Robots gained a point when they found the ‘food’ and lost a point when they stumbled across the ‘poison’.

Crucially, the researchers could electronically ‘breed’ the robots to improve their neural networks, so they could compare how the offspring of different combinations of best and worst performing robots would behave.

Zimmer notes some of the interesting results:

Here, however, is where the experiment got really intriguing. Each robot wears a kind of belt that can glow, casting a blue light. The scientists now plugged the blue light into the robot circuitry. Its neural network could switch the light on and off, and it could detect blue light from other robots and change course accordingly. The scientists started the experiments all over again, with randomly wired robots that were either related or unrelated, and experienced selection as individuals or as colonies.

At first the robots just flashed their lights at random. But over time things changed. In the trials with relatives undergoing colony selection, twelve out of the twenty lines began to turn on the blue light when they reached the food. The light attracted the other robots, bringing them quickly to the food. The other eight lines evolved the opposite strategy. They turned blue when they hit the poison, and the other robots responded to the light by heading away.

Two separate communication systems had evolved, each benefiting the entire colony.

The researchers have made some Quicktime video available if you want to see this in action and the scientific paper is available as a pdf file.

The research was led by Prof Laurent Keller, a biologist who specialises in understanding the evolution of communication networks.

There’s much more about this fascinating experiment and the other surprising types of behaviour that emerged from it over in Zimmer’s article.

Link to article Carl Zimmer’s article ‘Evolving Robotspeak’.
pdf of scientific paper.

The social intelligence hypothesis

ABC Radio’s Science Show just had a special edition on the evolution of the brain and the development of social intelligence.

The programme talks to some of the leading researchers in social intelligence whose research interests range from comparing the behaviours of animals across species, to neuroimaging humans, to building robots to mimic social interaction.

In particular, the programme tackles the ‘social intelligence hypothesis’ that suggests that our increase in brain size during evolution has been driven by the need to work in groups and make sense of complex relationships.

Prof Steven Mithen explains:

There seems to be two key figures of brain expansion, and I think this is where the social intelligence hypothesis becomes very interesting. The first was around two million years ago, and at that time brains expanded perhaps about 50%. So we went from brain size of around 450cc to a brain size of around 1,000cc by 1.8 million years ago. What’s interesting during that time is that we don’t see dramatic changes in human behaviour as represented by the archaeological remains….

So archaeologists asked; why are brains getting larger and what is it providing? Brains wouldn’t get larger just for any reasons because brain tissue is metabolically very expensive, so it’s got to be serving a really important purpose. I think the social intelligence hypothesis suggests to us that that expansion of brain size around two million years ago was because people were living in larger groups, more complex groups, having to keep track of different people, a larger number of social relationships which we simply required a larger brain to do.

Link to Science Show special on ‘The social intelligence hypothesis’.