The above is an excerpt from Cordeshi's book "Discovery of the Artificial".
Hugh Bradner was at the Psychology laboratory at the University of Miami, Ohio. His robot learnt by trial and error. The cart was 12 inches long, 6 inches wide with 2 wheels on a front axle. a driving wheel in the middle, and a steering wheel located near the rear.
H. Bradner, A new mechanical "learner," Journal of General Psychology, 1937 17: pp414-419