The Tortoises That Inspired Modern Robotics

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A pioneer in the study of brain activity then created the first autonomous robots: a pair of charming turtles that knew how to make their way around a room.

Neurophysiologist W. Gray Walter was born on this day in 1910 in Kansas City, Missouri. After studying at the University of Cambridge, he joined the research team at the Maudsley Hospital in London. There he built machines that measured the brain’s electrical activity.

Electroencephalography (EEG), which records this data via electrodes placed on the scalp, was first imagined in 1929 by German psychiatrist Hans Berger. He tried to achieve this with an existing instrument called a galvanometer.

Shortly after Berger’s paper was published, scientists investigated how EEG could be used with patients. At Maudsley Hospital, neuropsychiatrist Frederick Lucien Golla helped Walter create more advanced EEG devices. Over the next decades, Walter made major advances in EEG research. In 1936, for example, he was the first to identify a brain tumor using this technique. He also discovered brain waves called delta waves, associated with deep sleep.

For Walter’s next feat, he dove into the emerging world of cybernetics, or “the scientific study of control and communication in animals and machines,” according to the movement’s founder, Norbert Wiener. Researchers in this field hoped to learn more about animal behavior from machines.

Along the same lines, Walter designed robots to shed light on the inner workings of animal brains. Walter had hypothesized that connections between a minimal amount of brain cells could direct complex behaviors, an idea he explored with turtle-like robots.

He built his first iterations, Elmer and Elsie, between 1948 and 1949. At the time, new developments in electronic motors and computers made it possible to imitate animal intelligence. Elmer and Elsie had brains made of two vacuum tubes, which Walter likened to neurons. These slow robots had a plastic shell and turtle-like appearance, although their name came from a Alice in Wonderland character.

Read more: “What we misunderstand about robots”

They moved on three wheels and interacted with their environment based on the senses of touch and sight. The robot’s “eye”, a rotating photocell, looked around for light. Another sensor detected whether the shell hit something, prompting the robot to turn away. The system allowed the robot reptiles to explore a room and even ordered them to visit a hutch to recharge their batteries. This robot “explores its environment actively, persistently and systematically, as most animals do,” according to Walter.

They even had free will, Walter suggested in a 1950 issue of Scientific Americanand sometimes did the unexpected; for example, the robot began “wobbling, warbling and wriggling like a clumsy narcissus” in front of a mirror, he noted. “The behavior of a creature thus engaged in its own reflection is quite specific and, on a purely empirical basis, if observed in an animal it might be accepted as evidence of a certain degree of self-consciousness.” Walter considered them the beginnings of a new species, which he called Speculator Machina.

With his next turtle, Walter wanted to infuse memory into the device. We called him Machina docilis, a word that translates to teachable in Latin. This model had similar internal workings, but it also included a sound detector. M. docile could be trained to learn specific behaviors stimulated by light, sounds or shocks against objects, a process inspired by Pavlovian learning. In fact, Walter had even met the Russian physiologist Ivan Pavlov in his youth.

Walter inspired future generations of scientists by blending biology and robotics, and he showed that even simple machines can behave in surprising ways – an early foray into the field of artificial intelligence that now dominates our daily lives.

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Main image: UWE Bristol

• Molly Glick

  Published on February 19, 2026

  Molly Glick is the newsletter editor of Nautilus.