The investigator, dressed incongruously in sweater and tie and holding a small metal box, stands in a bullring. He taunts a bull with a gesture of his hand. Suddenly the bull faces him and charges. Taking a couple of steps back, the investigator presses a button on the box to send a radio signal, and the bull halts in mid-stride. It turns away. The animal’s natural aggression has evaporated.
This risky behavior-control demonstration, conducted in Spain in 1963, was the signature experiment of José Manuel Rodríguez Delgado, a physiologist and scientific showman who explored the varied responses of the brain to electrical stimulation.
During the middle decades of the twentieth century, Delgado grew notorious for using electricity to elicit rage, anxiety, pleasure, drowsiness, and involuntary movements in his animal and human subjects. Critics complained that he was paving the way for mind control; Delgado countered that changing the functioning of brains through electrical stimulation was not necessarily a bad thing.