A brush with death led Hans Berger to invent a machine that could eavesdrop on the brain.
In 1893, when he was 19, Berger fell off his horse during maneuvers training with the German military and was nearly trampled. On that same day, his sister, far away, got a bad feeling about Hans. She talked her father into sending a telegram asking if everything was all right.
To young Berger, this eerie timing was no coincidence: It was a case of “spontaneous telepathy,” he later wrote. Hans was convinced that he had transmitted his thoughts of mortal fear to his sister — somehow.
So he decided to study psychiatry, beginning a quest to uncover how thoughts could travel between people. Chasing after a scientific basis for telepathy was a dead end, of course. But in the attempt, Berger ended up making a key contribution to modern medicine and science: He invented the electroencephalogram, or EEG, a device that could read the brain’s electrical activity.
Berger’s machine, first used successfully in 1924, produced a readout of squiggles that represented the electricity created by collections of firing nerve cells in the brain.
In the century since, the EEG has become an indispensable clinical tool.
