Get best of the week

Meet the cybernetic turtle, the predecessor of Roomba

Using only a photocell, a touch sensor and two electronic lamps, the robot turtle imitated the movements of real animals



Neurophysiologist Gray Walter put together this cybernetic turtle to explain brain functions.In the

family tree of robots, Roomba ancestors were probably Elmer and Elsie, a pair of cybernetic turtles invented in 1940 by neurophysiologist Gray Walter . Robots could “see” thanks to a rotating photocell directing them to a light source. If the light became too bright, they retreated and began to explore the environment in a different direction. When colliding with an obstacle, the touch sensor made the turtles turn back and change direction. Thus, Elmer and Elsie explored their surroundings.

Walter was one of the first researchers in electroencephalography (EEG) - a technique for reading the electrical activity of the brain using electrodes attached to the scalp. Among his notable clinical breakthroughs is the first diagnosis of a brain tumor made by EEG. In 1939, he joined the newly founded Neurological Institute. Burden in Bristol, England, as head of the Department of Physiology, and worked there until the very end of his career.

The Norbert Wiener Cyber ​​Movement Spawns a Whole Zoo of Cybernetic Creatures


In the late 1940s, Walter fell into an expanding community of scientists interested in cybernetics. The founder of this field, Norbert Wiener defined cybernetics as "the scientific study of control and interaction in systems such as animals or machines." In the first wave of cybernetics, people sought to assemble machines that simulate animal behavior. Claude Shannon was played with a robot mouse named Theseus, capable of passing through mazes. William Ross Ashby created the Homeostat , a device that adapts to incoming signals so as to remain in a stable state.

Walter's contribution to this cybernetic zoo was an electromechanical tortoise, on which he began working in the spring of 1948 in his spare time. The first samples were inelegant. In 1951, U.J. Warren, nicknamed The Bunny, an electrical engineer from the Burden Institute, assembled six better turtles for Walter. Two of them became Elmer and Elsie - Gray composed these names from clumsy acronyms: ELectro MEchanical Robots, Light Sensitive, with Internal and External stability [light-sensitive electromechanical robots with external and internal stability].


1950 timelapse photo - Walter smokes while one of his cybernetic turtles walks around the living room

Walter considered Elmer and Elsie Adam and Eve a new species, Machina speculatrix [mechanism learning]. The scientific designation reflected the study or research nature of robots. The creatures had a smooth protective case and an elongated neck, so Walter carried them to the Linnean family Testudo, that is, to the turtles. Expanding the naming scheme, he named the Shannon mouse, passing through the labyrinths, Machina labyrinthia, and Ashby's homeostat - Homestat Machina sopora (sleeping mechanism).

Have the cybernetic turtles of Gray Walter demonstrated free will?


Each turtle moved on three wheels by means of two motors, one of which was responsible for movement, and the second for steering. The brain consisted of two electron tubes, which, according to Walter, were the equivalent of two working neurons.

Despite the limited equipment, according to his statements, turtles showed free will. In a May 1950 issue of Scientific American, he described how a photocell at the end of a turtle’s neck scans the environment for a light source. The photocell was connected to the steering gear, and during the search the turtle moved in circles. Walter compared this to the alpha rhythm of the electrical impulses of the brain, passing through the visual regions of the brain and at the same time emitting signals to the muscles that make them move.

In the dark room, the turtle wandered aimlessly. Finding the light, she moved directly to its source. But when exceeding a certain brightness, she retreated. With two sources, she moved here and there between them. “Like a moth striving for a flame,” Walter wrote of a tortoise changing its behavior between seeking and retreating from the light.

The turtle had its own navigation light, which turned on when searching for a light source. Initially, it was only needed to tell the observers which team the robot is processing, but it had unexpected consequences. If Elmer noticed himself in the mirror, he would begin to approach the image until the light became too bright, and then he retreated. In a 1953 book, The Living Brain, Walter compared it to a "clumsy daffodil."

If Elmer and Elsie were in the same room and saw each other's light, they began to move toward the source, and approached, then turn away to the side when they came too close. Walter, who easily described the behavior of machines in biological terms, called it a nuptial dance in which unhappy lovers can never "realize their 'desires."



The turtle shell was needed not only to protect its electromechanical insides. If the robot came across an obstacle, the pressure sensor forced it to turn on the reverse gear and change direction. Thus, the robot could study its environment, being, in fact, blind.

M. speculatrix was powered by a battery for a hearing aid and a 6 V battery. Finishing her adventures due to a sagging battery, she went to her hole. There she could connect to the contacts, turn off the motors and recharge.

Elmer and Elsie made a splash at the 1951 British festival


In the summer of 1951, Elmer and Elsie performed daily at the science fair of the 1951 British festival. The festival was held at several locations throughout the United Kingdom, and attracted millions of visitors. Turtles have gained immense popularity. Visitors watched their curious actions as they moved around their corral, moving towards and away from light sources, avoiding obstacles in their path. A third turtle with a transparent carapace was displayed in a display case to show its internal structure and advertise the components.

While M. speculatrix surprised the public, Walter studied the next generation of this species. Elmer and Elsie successfully demonstrated unpredictable behavior that could be compared to the simplest response of animals to stimuli, but they were not trained in experience. They had no memory, they could not adapt to the environment.

Walter called M. docilis his next experimental turtle, which means “trained” in Latin, and tried to create a robot that could imitate conditioned reflexes of animals according to Pavlov. Russian psychologist used dogs, food and sounds; Walter used cybernetic turtles, a light and a whistle. He trained his turtles M. docilis to perceive the sound of a whistle in the same way as light, and the turtle began to move to the sound even in the absence of light.

Walter published his findings on M. docilis in yet another article for Scientific American, Learning Machine . The second article had a lot of interesting things for electrical engineers, in particular, circuit diagrams and a technical discussion of the problems that arise when creating robots, for example, amplification of the whistle sound, necessary due to the noise of the motors.


One of the turtles returns to the hole to recharge the batteries

The brain of M. docilis was the CORA scheme (COnditioned Reflex Analog, “an analogue of conditioned reflexes”), which recognized the repeated arrival of simultaneous signals on different channels - for example, light and sound recognized simultaneously. Having fixed a certain number of repetitions, from 10 to 20 pieces, CORA made connections with the resulting behavior, which Walter described as a conditioned reflex. CORA could both learn behavior and forget about it. If the operator teased the turtle without turning on the light at the same time as the sound, CORA eliminated the established connection between the events.

At the end of the article, Walter admitted that, although it would be realistic to conduct future experiments with a large number of circuits and input signals, the cost of complication would be a decrease in stability. As a result, scientists realized that simulating behavior and understanding reactions to several stimuli is too complicated a task.

After the creation of CORA, Walter stopped experimenting with robotic turtles, and no one began to continue his research. As historian Andrew Pickering noted in his 2009 book Cybernetic Brain, “CORA remains an unexplored resource in the history of cybernetics.”

Walter's legacy is alive in his turtles. Ruben Hogget has put together a valuable collection of archival information about Walter's turtles, which can be found on his Cybernetics Zoo website.“Three turtles from the British festival were auctioned off, and their new owner, Wes Clutterbuck, gave them the names Slo, Mo and Shan. Two turtles were then destroyed by fire, but the one that had transparent shell, the Clutterback family donated to the Smithsonian Institution. The second of surviving to this day turtles from the first six, created by the "Hare" by Warren, is stored in the Museum of Science in London. Now it is exhibited in the gallery "Creation of the modern world."

More articles:


All Articles