An electrical robot "animal" resembling a tortoise is used by Dr W. Grey Walter in his researches into the nature and function of the brain. The "tortoises" are controlled by a mechanism switch which reproduces some of the elementary functions of the human brain. They are not stimulated by light and touch so that a beam of light in a darkened room will draw the tortoise toward it and any obstacles in the machine's path will be rounded. If the machine is offered several alternative sources of light it will investigate each one in turn, losing interest in each as it becomes too bright. Perhaps the most astonishing thing that these machines can do is to return to their "hutch" and plug themselves into a battery charger when their portable batteries start to run down. Dr W. Grey Walter with a mechanical tortoise attracted from its hutch by a torch beam which it comes to investigate. 6th October 1953