“The Forgotten Era of Brain Chips,” published in Scientific American in October 2005, has provoked as much interest as anything I’ve ever written. It focuses on Jose Manuel Rodriguez Delgado, a pioneer in brain-stimulation research. I keep hearing from journalists and others wanting more information on Delgado, whom I interviewed in 2005 and who died in 2011. Delgado fascinates conspiracy theorists, too. An article on Infowars.com describes him as a “madman” who believed that “no human being has an inherent right to his own personality.” Given widespread interest in and misinformation about Delgado, whose work prefigures current research on brain implants (see “Further Reading”), I’m posting an edited version of my 2005 article. --John Horgan

Once among the world’s most acclaimed scientists, Jose Manuel Rodriguez Delgado has become an urban legend, whose career is shrouded in misinformation. Delgado pioneered that most unnerving of technologies, the brain chip, which manipulates the mind by electrically stimulating neural tissue with implanted electrodes. Long a McGuffin of science fictions, from The Terminal Man to The Matrix, brain chips are now being tested as treatments for epilepsy, Parkinson’s disease, paralysis, depression, and other disorders.

In part because it was relatively unencumbered by ethical regulations, Delgado’s research rivaled and even surpassed much of what is being done today. In 1965, The New York Times reported on its front page that he had stopped a charging bull in its tracks by sending a radio signal to a device implanted in its brain. He also implanted radio-equipped electrode arrays, which he called “stimoceivers,” in dogs, cats, monkeys, chimpanzees, gibbons, and humans. With the push of a button, he could evoke smiles, snarls, bliss, terror, hunger, garrulousness, lust, and other responses.

Delgado described his results in hundreds of peer-reviewed papers and in a widely reviewed 1969 book, but these are rarely if ever cited by modern researchers. One reason may be that in 1974 he left Yale, his base for more than two decades, to return to Spain, his birthplace. He was at the peak of his career. A cover story in The New York Times Magazine had just hailed him as the “impassioned prophet of a new ‘psychocivilized society’ whose members would influence and alter their own mental functions.”

In Madrid, Delgado switched his focus to non-invasive brain-stimulation methods, anticipating current exploration of techniques such as transcranial magnetic stimulation. Because he published primarily in Spanish journals, his work fell into obscurity. Brain-implant studies back in the U.S. became engulfed in ethical controversies. Grants dried up, researchers drifted to other fields, and little work was done until the recent revival. Meanwhile, conspiracy theorists began depicting Delgado as a fascist who sought to enslave people by means of neurotechnology.

In 2004, Delgado and his wife Caroline--a Yale administrator’s daughter whom he married in 1956, when she was 22 and he was 41--moved to San Diego, California, to be closer to their son and daughter. Delgado recently allowed me to visit him at his elegant, one-story home. Over the course of two days, Delgado, who at 89 is charming, courtly, and keen of mind, told me his life story and vigorously defended his legacy. He describes himself as a libertarian and pacifist, whose goal as a scientist was to liberate us from our biology, and especially from mental illnesses and violent aggression.

Delgado understands why many people are offended by research into the physiological processes that underpin thoughts and behavior. They think, “How is it possible that I am mainly the result of chemicals in the brain! This is very distasteful, I don’t like this at all!” But if the research leads to better treatments for brain disorders, he says, “this is wonderful.”

Born in Ronda, Spain, in 1915, Delgado has been dogged by rumors that he supported the fascist regime of Francisco Franco. Someone at a scientific conference threw a pie in Delgado’s face for this alleged offense. But when Franco led a military coup against the Republican government of Spain in 1936, Delgado, then a medical student, enlisted in the Republican army and served as an officer in the medical corp. After Franco’s fascist troops crushed the Republicans, Delgado spent five months in prison before being released to resume his medical studies.

Delgado originally intended to become an eye doctor, like his father. But a stint in a physiology laboratory--plus exposure to the writings of the great Spanish neuroscientist Ramon y Cajal--left him entranced by “the many mysteries of the brain. How little was known then. How little is known now!” Delgado was fascinated by experiments by Swiss physiologist Walter Rudolph Hess. Beginning in the 1920s, Hess had demonstrated that he could elicit behavioral responses such as rage, hunger, and sleepiness in cats by electrically stimulating specific regions of their brains with wires.

After earning an M.D. and doctorate in physiology from the University of Madrid, Delgado joined its physiology laboratory, where he carried out brain-stimulation experiments on cats, dogs, and primates. In 1946, he won a fellowship at Yale, and in 1950 he accepted a permanent position in its department of physiology.

The department was headed by John Fulton, who played a crucial role in the history of psychiatry. In a 1935 lecture in London, Fulton reported that destroying the prefrontal lobes of a violent, “neurotic” chimpanzee made her calm and compliant. In the audience was Portuguese psychiatrist Edgar Moniz, who started performing lobotomies on psychotic patients and claimed excellent results. After Moniz won a Nobel Prize in 1949, lobotomies became an increasingly popular treatment for mental illness.

Initially shocked that his method of pacifying a chimpanzee had been applied to humans, Fulton later became a proponent of psychosurgery. Delgado never shared his mentor’s enthusiasm. “I thought Fulton and Moniz’s idea of destroying the brain was absolutely horrendous,” Delgado recalls. He felt it would be “far more conservative” to treat mental illness by applying electrical-stimulation methods pioneered by Hess, who shared the 1949 Nobel Prize with Moniz. “My idea was to avoid lobotomy,” Delgado says, “with the help of electrodes implanted in the brain.”

One key to Delgado’s scientific success was his talent as an inventor. A Yale colleague called him a “technological wizard.” In his early experiments, wires ran from the implanted electrodes through the skull and skin to bulky electronic devices that recorded data and delivered electrical pulses. This set-up restricted subjects’ movements and left them prone to infections. Delgado thus designed radio-equipped stimoceivers as small as quarters, which could be fully implanted in subjects. A battery pack strapped to the head or worn around the neck supplied the power transdermally. Delgado also invented implantable “chemotrodes” that could release precise amounts of drugs directly into the brain.

In 1952, Delgado co-authored what he claims is the first peer-reviewed paper describing deep brain stimulation of humans. Over the next two decades, he implanted electrodes in some 25 subjects. Most were schizophrenics and epileptics at the now-defunct State Hospital for Mental Diseases in Howard, Rhode Island, where Delgado’s occasional collaborator Hannibal Hamlin was a staff psychiatrist.

One striking reaction to stimulation was pleasure and sexual arousal. A 36-year-old female epileptic, whose behavior was normally “quite proper,” responded to stimulation by “giggling and making funny comments” and flirting with researchers. A sullen 11-year-old epileptic boy became chatty and friendly when stimulated. “Hey! You can keep me here longer when you give me these,” he exclaimed. He also announced, “I’d like to be a girl.”

The therapeutic benefits were mixed, however, and Delgado turned away more patients than he treated. One was a young woman whose parents had committed her to a mental hospital because she was so violent and promiscuous. Both the parents and the daughter herself pleaded with Delgado to operate on her, but he refused, saying that electrical stimulation was too unreliable. He achieved his best results treating people afflicted with chronic pain, including a man injured in an automobile accident. His pain had resisted drug treatment, but the stimoceiver relieved both his pain and the depression it had caused, so much so that he could return to work.  

Delgado seems reticent discussing his experiments on humans. He is more enthusiastic recalling research on monkeys, chimpanzees, and gibbons, which he kept both at Yale and in open-air compounds in the Bahamas and New Mexico. He explored the effects of stimulation not only on individuals but also on groups, and he did not shy away from anthropomorphic interpretations.

In one demonstration, he implanted a stimoceiver in a macaque who terrorized his cage-mates. Delgado installed a lever in the cage that, when pressed, would activate the stimoceiver in the bully and pacify him. A female in the cage soon figured out the lever’s significance and yanked it often and with gusto. “The old dream of an individual overpowering the strength of a dictator by remote control has been fulfilled, at least in our monkey colonies,” Delgado wrote.

Credit: Yale Events and Activities Photographs (RU 690). Manuscripts and Archives, Yale University Library

Delgado’s fascination with violent behavior led him to conceive his famous bull experiment. “I thought: Which is the animal which is characterized by his aggressive behavior? The fighting bull!” A Spanish university supplied the funds for the experiment, and a bull-breeder in Cordoba supplied four bulls and a bullring. Working with his wife and several assistants over three days in 1963, Delgado tranquilized the bulls, fitted stereotactic frames over their skulls, and inserted stimoceivers into their brains. Delgado then stood in a bullring with the bulls and stimulated their brains by pressing buttons on a hand-held radio.

Asked if he took bull-fighting lessons for these sessions, Delgado responds in mock outrage, “What do you mean! I know how to fight a bull!” He grew up, after all, in Ronda, a bastion of bullfighting. He admitted that he was “frightened” when one bull charged him and stopped in response to his frantic button-pushing just a few feet away from him. As word spread in Cordoba about the strange activities at the ranch, a Spanish television crew and hundreds of others gathered to watch Delgado carry out tests with different bulls.

The episode received its most significant media coverage two years later, after Delgado showed slides from the bull experiment during a lecture at the Museum of Natural History in New York City. Afterwards, a New York Times reporter approached him. “He said, ‘That was very interesting. Can I borrow your pictures?’ I said, ‘Sure, no problem.’”

The next day the Times published a front-page story, illustrated with a photograph of a bull just a few feet away from Delgado, about “the most spectacular demonstration ever performed of the deliberate modification of animal behavior through external control of the brain.” Delgado was swamped with media inquiries about how he had created a real-life version of “Ferdinand,” the gentle bull in a popular children’s story.

Not everyone was impressed. Elliot Valenstein, a neurophysiologist at the University of Michigan, contended that stimulation had not inhibited the bulls’ aggressive instinct, as Delgado had claimed, but had merely prevented it from charging straight ahead. In other words, the effect was strictly muscular. Valenstein offered a similar critique of an experiment in which Delgado claimed to have suppressed the “maternal instinct” of female monkeys. Asked now about Valenstein’s objections, Delgado shrugs. His experiment, he says, “naturally could be interpreted in one way or the other,” but he stands by his initial claims.

In terms of scientific significance, Delgado believes his experiment on a female chimpanzee named Paddy deserved more attention. Delgado programmed Paddy’s stimoceiver to detect distinctive signals, called spindles, emitted by her amygdala. Whenever the stimoceiver detected a spindle, it stimulated another part of Paddy’s brain, producing an “aversive reaction”--that is, a painful or unpleasant sensation. After two hours of this negative feedback, Paddy’s amygdala produced 50 percent fewer spindles; the frequency dropped by 99 percent within six days. Delgado speculated that this “automatic learning” technique could be used to quell epileptic seizures, panic attacks, or other brain disorders.

In 1969, Delgado described brain-stimulation research and discussed its implications in Physical Control of the Mind: Toward a Psychocivilized Society. Ashley Montagu, a leading psychologist, called the book “an invaluable and authoritative analysis of the nature of human nature.” Scientific American’s Phillip Morrison called it “a thoughtful, up-to-date account” of electrical-stimulation experiments but added that the research was “somewhat ominous.” Indeed, many readers found Delgado’s book—illustrated with photographs of monkeys, cats, and two young women with stimoceivers affixed to their skulls—horrifying.

Some of Delgado’s rhetoric had an alarmingly apocalyptic tone. He declared that humanity was on the verge of “conquering the mind,” and should shift its mission from the ancient dictum “Know Thyself” to “Construct Thyself.” Used wisely, neurotechnology could help create “a less cruel, happier, and better man.” His attempts to extol brain electrodes could be almost comically clumsy. He noted that female patients “have shown their feminine adaptability to circumstance by wearing attractive hats or wigs to conceal their electrical headgear.”

The sponsorship of his experiments by the Office of Naval Research and the Air Force Aeromedical Research Laboratory (as well as several civilian agencies) raised eyebrows as well. Critics speculated that the military wanted to create cyborg soldiers that could kill on command, like the brainwashed assassin in The Manchurian Candidate. Delgado says his military sponsors never expressed interest in such applications. “At that time, the technology was very crude. The only thing we could do was to increase or decrease aggressive behavior, but not to direct aggressive behavior to any specific target. Maybe they expected that. I don’t know.”

The 1970 book Violence and the Brain, which explored potential applications of neurotechnologies, also attracted unwanted attention. The book was by Frank Ervin and Vernon Mark, brain-implant researchers at Harvard with whom Delgado briefly collaborated. (One of Ervin’s students was Michael Crichton, whose first bestseller, The Terminal Man, about a bionic experiment gone awry, was inspired by the research of Ervin, Mark, and Delgado.)

Ervin and Mark suggested that neurotechnologies might quell the violent tendencies of African-Americans who rioted in inner cities. Brain-implant experiments of Robert Heath, a psychiatrist at Tulane University, provoked still more controversy. In 1972 Heath claimed that he had changed the sexual orientation of a male homosexual by stimulating his brain’s septal region while he had intercourse with a female prostitute.

The fiercest critic of brain implants was psychiatrist Peter Breggin (who later focused on the dangers of psychiatric drugs). In testimony submitted into the Congressional Record in 1972, Breggin lumped Delgado, Ervin, Mark, and Heath together with proponents of lobotomies and accused them of seeking “a society in which everyone who deviates from the norm” will be “surgically mutilated.” Quoting liberally from Physical Control, Breggin singled out Delgado as “the great apologist for Technological Totalitarianism.” (Breggin’s testimony is apparently the source of erroneous Internet claims that Delgado once testified before Congress.)

As Delgado’s notoriety grew, strangers started accusing him of having implanted “stimoceivers” in their brains. One woman who made this claim sued Delgado and Yale University for $1 million, although he had never met her. In the midst of this brouhaha, the Spanish minister of health asked Delgado to help organize a new medical school in Madrid, and Delgado accepted. He and his family moved to Spain in 1974. Delgado insists he was not fleeing the controversy triggered by his research. The Spanish minister just gave him an offer too good to refuse. “I said, ‘Could I have the facilities I have at Yale?’ And he said, ‘Oh no, much better!’”  

In Spain Delgado shifted his focus to noninvasive neurostimulation methods--”because implanting electrodes, this is brutal,” he says in a mock-growly voice. He invented a halo-like device and a helmet that could deliver electromagnetic pulses to specific neural regions. Testing the gadgets on animals and human volunteers, including himself and his daughter, Delgado discovered that he could induce drowsiness, alertness, and other states. He and his colleagues also had success treating tremors of Parkinson’s.

This research, too, attracted controversy. The 1984 BBC documentary Opening Pandora’s Box cited Delgado’s work as evidence that the U.S. and Russia were developing methods for remotely modifying peoples’ thoughts. Noting that the power and precision of electromagnetic pulses falls off dramatically with distance, Delgado doubts whether remote mind-control is possible. “This was science fiction, probably.”

Delgado is not upset that modern scientists seldom mention his work. “Always there are antecedents in a field,” he says. He doubts that modern brain-stimulation researchers avoid citing him because he is so controversial. Simple ignorance, he says, is a more likely explanation. After all, most modern databases do not include publications from his heyday in the 1950s and 60s.

Looking back over his career, Delgado acknowledges “a great defect: I have been able to do many important things, but I have not been able to follow in depth in any of these fields.” He is thus thrilled that a new generation of scientists--equipped with increasingly sophisticated computers, electrodes, and brain-scanning technologies--is exploring paths that he trail-blazed. “In the near future,” he says, “I think we will be able to help many human beings, especially with the non-invasive methods. Maybe invasive also.”

Delgado has constructive criticism for his scientific descendants. He believes some neuroscientists are too obsessed with linking specific cognitive mechanisms to specific neural regions. Just because you can stimulate a spot in the motor cortex and get a finger to flex does not mean that region alone is responsible for moving the finger.

“People are trying to investigate: Where is the area of the brain essential to consciousness? That’s a silly question,” because consciousness and cognition in general almost certainly stem from the workings of the entire brain. “The whole brain is involved in everything!”

Delgado’s appreciation of the brain’s complexities leads him to doubt whether neurotechnologies will ever advance as far as some of us fear, or hope. “We know far more than 20 years ago, but there are so many things we don’t know.” He points out that neuroscientists have no idea how complex information is encoded in the firing of neurons. Moreover, brain stimulation can only modify skills and capacities that we already possess. It cannot make us instant experts in, say, quantum physics or French, as some critics have feared.

“Learning a language means slowly changing connections which are already there,” Delgado explained. “I don’t think you can do that suddenly.” Delgado is even more doubtful that we will soon transcend our biology entirely, as the artificial-intelligence researcher Ray Kurzweil and others have prophesied. “In 300,000 years maybe,” he says.

But Delgado looks askance at the suggestion of the White House Council of Bioethics and others that some scientific goals should not be pursued, particularly if they threaten to alter human nature. To be sure, technology “has two sides, for good and for bad,” and we should do what we can to “avoid the adverse consequences.” We should try to prevent potentially destructive technologies from being abused by authoritarian governments to gain more power, or by terrorists to wreak destruction.

But human nature, Delgado asserts, echoing one of the exhilarating and slightly scary themes of Physical Control, is not static but “dynamic,” constantly changing as a result of our compulsive self-exploration. “Can you avoid knowledge?” Delgado asks. “You cannot! Can you avoid technology? You cannot! Things are going to go ahead in spite of ethics, in spite of your personal beliefs, in spite of everything.”

Further Reading:

The Singularity and the Neural Code

Return of Electro-Cures Exposes Psychiatry's Weakness.

Much-Hyped Brain-Implant Treatment for Depression Suffers Setback.

Much-touted Deep-Brain-Stimulation Treatment for Depression Fails Another Trial

Patient in Failed Depression-Implant Trial Tells His Painful Story.

Why “Optogenetic” Methods for Manipulating Brains Don’t Light Me Up

Why Optogenetics Doesn’t Light Me Up: The Sequel

Do Big New Brain Projects Make Sense When We Don't Even Know the "Neural Code"?

Why You Should Care about Pentagon Funding of Obama's BRAIN Initiative.

Two More Reasons Why Big Brain Projects Are Premature.

Artificial brains are imminent… not!

What’s the Biggest Science News? We’re Still Human, for Ill or Good.

What Are Science's Ugliest Experiments?