On April 27, 1982, members of the California Assembly’s Consumer Protection and Toxics Committee gathered in Sacramento to hear Robert Plant endorse Satan. This was not a straightforward testimonial. For one thing, the Led Zeppelin frontman wasn’t actually in attendance. Also, his pro-devil paeans could only be heard when you played “Stairway to Heaven” backwards.

After circulating pamphlets with the “backward masked” declarations spelled out, that’s precisely what Assemblyman Phillip Wyman and panel witness William H. Yarroll II did. The relevant portion of the eight-minute classic was first played forward for committee members and then reversed. Here’s what Wyman claimed could be heard: “I sing because I live with Satan. The Lord turns me off. There’s no escaping it. Here’s to my sweet Satan.” Yarroll, who identified himself as a “neuroscientist,” noted that a teenager need only listen to “Stairway to Heaven” three times before these backward messages were “stored as truth.”

It wasn’t just Plant reverse-singing Satan’s praises, either. According to Yarroll, bands ranging from Styx to the Beatles also had secret backmasked messages hidden in their music—messages that, in the words of legislative proposal A.B. 3741, had the power to “manipulate our behavior without our knowledge or consent and turn us into disciples of the Antichrist.”

As the bill’s sponsor, Wyman wanted mandatory warning labels on all rock albums containing these morally dubious backward messages. “Suppose young people have heard ‘Stairway to Heaven’ two or three hundred times and there has been implanted in their subconscious mind pro satanic messages or incantations?” he told Terry Drinkwater the following day on a CBS Evening News segment. Indeed, this was the truly insidious part of backmasking. Even though you had to play records in reverse to decipher the occultic messages, they could still subliminally imprint themselves upon young teen minds when played in the standard direction.

During the same news segment, Yarroll described how the brain unscrambles a backward masked message: “We have it stored in the unconscious as a truth image,” he said, “and as the creative unconscious side of the brain does, it goes through scanning the unconscious brain to go about and bring those truth images to the surface and make them reality for us.”

After calling the issue “exciting and interesting,” committee chairman Sally Tanner (D-El Monte) delayed an official vote until the music industry and band members could weigh in on the matter. That day never came. But the national panic surrounding subliminal satanic messages in rock music was about to reach fever pitch.

In the early ’70s, backmasking—or the practice of recording vocals and instruments backwards and then reinserting them into the forward mix of a song—was something a music savvy (and possibly stoned) Beatles fan might bring up. A decade later, it had become a cause célèbre for conservative religious leaders, school teachers, parents, and even politicians. Whether it was the reversed voice of Freddie Mercury declaring “it’s fun to smoke marijuana” on “Another One Bites the Dust” or Styx imploring Satan to “move through our voices” on “Snowblind,” there seemed to be mounting evidence that rock music was literally becoming a mouthpiece for the devil.

Believers held record-smashing parties, appeared on popular TV talk shows, wrote books, formed watchdog groups, and, perhaps most importantly, called their government representatives to warn them.

By 1982, state and federal legislation was being introduced at a steady clip to combat rock and roll’s hidden satanic agenda. Two weeks after the California Assembly hearing in Sacramento, California congressman Robert Dornan introduced H.R. 6363 to the House. Also known as the “Phonograph Record Backward Masking Labeling Act,” the bill aimed to do the same thing as Wyman’s A.B. 3741, only on a national level. 

While it would ultimately be shuffled off to the Subcommittee on Commerce, Transportation and Tourism to die, other bills—including one in Arkansas a year later—were passed unanimously by both house and senate members (then-Governor Bill Clinton ultimately vetoed that one).

For its own part, the music industry responded with a bemused skepticism. Styx’s James Young called the whole idea of satanic backmasking a hoax perpetrated by religious zealots, and refused to attend any meeting or hearing where the topic was discussed. Then there was Bob Garcia of A&M Records, who declared, “it must be the devil putting these messages on the records because no one here knows how to do it.” A spokesman for Led Zeppelin’s record label, Swan Song Records, issued just one statement in response to the “Stairway to Heaven” satanic allegations: “Our turntables only rotate in one direction.”

Taken as a whole, these reactions only stoked the righteous (and possibly entrepreneurial) fires of religious leaders like pastor Gary Greenwald, who started holding backmasking seminars all over the country. Soon, books like Backward Masking Unmasked, Dancing With Demons, and The Devil’s Disciples: The Truth About Rock, were exposing “the sinister nature of rock and roll music,” while watchdog organizations like Parents Against Subliminal Seduction (P.A.S.S.) tried to block rock concerts at various venues.

The problem, as you may have already guessed, was that the whole thing was a bunch of diabolical tihsllub.

A drive-in movie theater in Fort Lee, New Jersey just happened to provide a perfect junk science laboratory. Over the course of six weeks in 1957, unsuspecting filmgoers were the subjects of a grand marketing experiment. Using a special high-speed projector, researcher and social psychologist James Vicary inserted the words “drink Coke” and “eat popcorn” into movies that summer. Invisible to the human eye, each message lasted for 1/3,000th of a second and was repeated in five-second intervals during films on alternating nights.

By the end of the six weeks, Vicary claimed 45,699 people had been subjected to his subliminal inducements. He also claimed that popcorn and Coke sales went up 57.5 and 18.1 percent, respectively. At a press conference held later that same year, Vicary described the results of this now infamous study to help boost interest in his new “Subliminal Projection Company,” an attempt to commercialize what he called a major breakthrough in subliminal advertising. The public and press went bonkers, and not in a good way.

The first sentence of an influential op-ed responding to the press conference by journalist Norman Cousins read: “Welcome to 1984.” He, like many others, wondered what such a technology could mean not just for advertisers who wanted to sell us stuff, but also for governments seeking to steer public sentiment.

For its own part, the FCC almost immediately threatened to suspend the broadcast license of any company that dared use Vicary’s machine. In the years following the experiment, the CIA started looking into the “operational potential of subliminal perception” (they found it “exceedingly limited”), and authors like Wilson Bryan Key began cranking out books such as Subliminal Seduction, which claimed that sexual images (and the actual word “sex”) were being hidden in hundreds of ads.  

But when the Canadian Broadcasting Corporation tried to replicate Vicary’s claims by subliminally flashing the message “Call now” during a popular Sunday night program, there was no increase in phone calls. The station later told viewers they had inserted a message and asked them to guess what it might have been. Almost half of the roughly 500 viewers claimed to have been made hungry or thirsty during the show, which aired during dinner time.

Vicary’s study was clearly on the public’s mind, which was problematic because it was completely made up. From the beginning, Vicary refused to release key details about his study. Not only was there never any independent evidence to support his claims about the effectiveness of subliminal advertising, years later, Vicary admitted he had done only enough research to file a patent for his machine, and actually had collected barely any data. Even worse, his machine didn’t seem to work half the time once people did try to test it.

Of course, none of that mattered by the late ’70s and early ’80s. Subliminal messaging was being used in self-help tapes, in department store Muzak to ward off shoplifters, and, if you believed Key, to sell the American public lots and lots of booze and cigarettes.

It’s amazing what social science research gets out into the public consciousness and causes concern, although I suppose that “you’re being manipulated and you don’t even know it!” might be especially alarming to people. But I’m not surprised, after all these years, to read that the experiment wasn’t replicable – this is the fate of a lot of psychological research, unfortunately. And as far as “hidden persuasion” goes, why not focus on what actually is out there in plain sight? Advertisers use all sorts of non-subliminal techniques to get you to behave in certain ways. Learning about those, so as to realize what’s going on, is always useful – much more than trying to discern any secret hidden messages. Backmasking seems even less plausible – does the mind really have the ability to turn words around subconsciously, and then to obey what you’ve “heard”? Again, why not focus on the actual lyrics and image that rock bands project? Some 1980s heavy metal bands flirted openly with Satanic imagery, and I didn’t like that, but even at the time it seemed to be mostly an act, calculated to offend the squares.