International Encyclopedia of Systems and Cybernetics

The British neurologist W. Grey WALTER experimented during the fifties with a device which he described as follows: "The machine… is a small creature with a smooth shell and a protruding neck carrying a single eye which scans the surroundings for light stimuli. Because of its general appearance we call the genus "Testudo" or tortoise…

"(The device) contains but two functional elements: two miniature radio tubes, two sense organs, one for light and the other for touch, and two effectors or motors, one for crawling and the other for steering" (1955, p.126).

The set received its energy from two small batteries. WALTER added: "The number of components in the device was deliberately restricted to two in order to discover what degree of complexity of behavior and independence (Note: we should say "autonomy") could be achieved with the smallest number of elements connected in a system providing the greatest number of possible interconnections.

"From the theoretical standpoint two elements equivalent to circuits in the nervous system can exist in six modes; if one is called A and the other B, we can distinguish A, B, A+B, A>B, B>A, and A.B as possible dynamic forms. To indicate the variety of behavior possible for even so simple a system as this, one need only to mention that six elements would be more than enough to form a system which would provide a new pattern every tenth of a second for 280 years – four times the human lifetime of 70 years" (p.126-7).

Machina speculatrix displayed indeed a very complex behavior and still more so when two of them were in the field, falling even sometimes in a double-bind behavior, or appearing to have some degree of self-awareness. WALTER's research was appearently not carried along, but becomes now renewed in the guise of new experiments on groups of more or less elemental automata, endowed with directive correlations (see for ex. J. ERCEAU, & J. FERBER, 1991).