Michael Gasperi's Extreme NXT Index has an intriguing article about the Machina Speculatrix, early artificial life experiments promoted over fifty years ago by british scientist William Grey Walter:
Machina Speculatrix
http://www.extremenxt.com/walter.htm
Over fifty years ago W. Grey Walter started building three wheeled, turtle like, mobile robotic vehicles. These vehicles had a light sensor, touch sensor, propulsion motor, steering motor, and a two vacuum tube analog computer. Even with this simple design, Grey demonstrated that his robots exhibited complex behaviors. He called his creation Machina Speculatrix after their speculative tendency to explore their environment. The Adam and Eve of his robots were named Elmer and Elsie (ELectro MEchanical Robots, Light Sensitive).
Learning of experiments like this, that were so succesful so early in the history of computers – and that took so long to be reimplemented in much more powerful digital computers – always makes me wonder: is intelligence really that hard a problem, or have we just been on the wrong track all along?
Stephen Wolfram would certainly have something to say about it...