Subliminal sounds are sonic events that slip beneath the threshold of conscious perception. Intentionally fleeting and unrecognizable to an unaware listener, these sounds were once believed to exert a deep psychological impact—and thus held the potential to be weaponized or misused. While audio is certainly not the only domain where subliminal effects have been explored, it remains at the core of human communication and was at the very forefront of the phenomenon’s unfolding. That history is nothing short of fascinating, involving a strange and tangled intersection of science, pseudo-science, politics, religion, and pop culture.

In this article, I’ll retrace that history, unpack the known extent of capabilities of subliminal audio, and explore a few concrete techniques, and creative approaches for embedding secret messages into sound. In a recent piece, I wrote about sound as code—a phenomenally multidimensional medium capable of layering and transporting vast amounts of information. Subliminal audio adds another angle to this story, outlining extraordinarily complex and strange relationships between sound, and its effect on our perception of the world. Let's dive in.

The Origins Of Subliminal Communication

By the time Suicidal Tendencies released their single "Subliminal" (1983), the moral panic regarding mind control and subliminal persuasion was already spreading like wildfire across the United States. If you ever dabbled in punk and thrashcore, you may recall the song's dystopian lyrics:

Flashing pictures on my screen

Shown too quickly to be seen

Does not register in the conscious mind

Propaganda of another kind

They're f-ing with me subliminally

They're f-ing with me subliminally...

Defiant and satirically paranoid, the words of the song reflect the growing public anxiety of subconscious influence that was happening in the 1980s. However, the seeds of the notion of subliminal influence were sown long before the term itself got popularized. It all started with the psychological theories about subconscious perception and suggestion developed by 19th-century forerunners of the field, most notably Sigmund Freud and William James. While neither addressed subliminal techniques directly, their theories set the foundation for modern understanding of the unconscious mind. Freud was the one to observe that significant mental activity occurs below conscious awareness, and thus, he reasoned, thoughts and behaviors could be influenced surreptitiously. Similarly, James, whose own work was concerned with the nature of consciousness in a broader sense, also emphasized the vitality of subconscious processes, and their great effect on our experience of life.

Then, in 1917, Austrian neurologist and psychologist Otto Poetzl, set out to conduct an experiment to test Freud's theory. Poetzl wanted to determine whether images, when presented so briefly that the participants could not consciously perceive them, would nevertheless affect their subsequent mental imagery and dreams. Using a tachistoscope—a device specifically designed to display pictures or text for a predetermined amount of time—Poetzl exposed the participants of the experiment to a series of complex flickering line drawings, which only appeared for about 1/100 of a second. When asked after the experiment was over, participants typically said that they have, in fact, not seen anything. In the second part of the experiment, the participants were asked to engage in free drawing, fantasizing, or to describe dreams that arrived either shortly after the experiment or following a night's sleep. Upon the results of the study, Poetzl concluded that the influence of the briefly flashed images on the psyche of the participants was evident: many have reproduced details or created fantasies that were thematically or structurally related to the drawings that were beamed into their minds bypassing the awareness. This tendency for unconsciously perceived visual stimuli to reappear later in altered or disguised forms in dreams or imaginative productions became popularly known as the Poetzl Effect.

However, at that stage the results were not reproduced repeatably, the understanding of the effect remained sparse, and the general consensus on the matter was far from conclusive. Media companies, advertisers, and government agencies nevertheless started experimenting with subliminal influence early on… you know, just in case it did work. Some of the initial attempts to use subliminal messages on a wider public came in animated films, produced by Warner Brothers and Disney.

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A commonly cited example is the cartoon Wise Quacking Duck, released in 1943 during the peak of WWII. In one of the scenes, as Daffy Duck casually lives out the cartoonishly classic chaotic mischief, he momentarily passes by a statue which for a few frames flashes a "Buy Bonds" message to the unaware audience. Reportedly, this was a marketing attempt by the United States government to attract its citizens to buy bonds as a patriotic duty to support the ongoing war effort.

Advertising companies, as one would expect, were indeed particularly attracted subconscious persuasion. Among the first to promote the idea was an Austrian psychologist Ernest Dichter, a key figure in the development of motivational research, who emigrated to the United States in 1938. Dichter applied Freudian psychoanalytic theories to consumer behavior, arguing that people’s purchasing decisions were driven not just by utility but by deep-seated desires, fears, and aspirations. Rather than seeking control in an authoritarian sense, Dichter believed that by tapping into the unconscious, advertisers could help people find meaning and identity through products. In his view, symbolic consumption could act as a stabilizing force in a democratic society, biasing it toward emotional satisfaction, and away from ideological extremism.

Combining rigorous interviews with people along with psychological analysis, Dichter's goal was to uncover people's hidden desires and fears that could be addressed through marketing. He posited that products could serve as symbols of personal growth and self-expression, bridging consumption with identity and emotional fulfillment. Needless to say, the idea really resonated with tobacco, alcohol, and cosmetics industries, who already in the 1940s and 1950s began to utilize visual suggestion, symbolism, and embedded imagery in their product advertisements.

Naturally, there were numerous critics, including journalist Vance Packard—who in The Hidden Persuaders (1957) portrayed Dichter’s approach as an assault on consumer autonomy—and writer-activist Betty Friedan, who in The Feminine Mystique (1963) rebuked advertising for the way it coaxed housewives into identifying with consumption, reflecting the same strategies Dichter employed. Yet, the theory and the approach were undoubtedly impactful for the marketing industry, and certainly set the vector for the field for years to come, with contemporary algorithm-driven approaches still echoing those original incentives.

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The year that subliminal persuasion reached the concerned minds of a wider public was 1957, primarily because of the controversial experiment conducted by marketing researcher James Vicary. Reportedly, the experiment involved visitors of a movie theater in Fort Lee, New Jersey, who unwittingly were exposed to quickly flashing messages like "Eat Popcorn" and "Drink Coca-Cola" during film screenings. To everyone's astonishment, Vicary claimed that as a result both, Popcorn and Coca-Cola, sales increased by 57.8% and 18.1% respectively.

Newspapers, magazines, and television shows picked up the story, amplifying it nationwide with cautionary headlines that implied “hidden persuaders,” and unseen forces influencing behavior. Packard dedicated a good amount of ink on Vicary and his approach in his book. This was further augmented by the wide-spread Cold War-era apprehensions regarding brainwashing, propaganda, and psychological manipulation. All in all, a fruitful soil for paranoid thinking and social anxiety. The concerns got so severe that the United States and British States governments issued outright bans on the use of subliminal priming in advertising.

However, as the years went on the results of the Vicary's study only raised more questions. All of the attempts of journalists to obtain study data from Vicary yielded no outcome, and moreover, several experiments that tried to recreate the study never reached results that were even remotely similar. The fact of the matter is that Vicary's research was made up, and not just the results: the experiment itself likely never even took place. Five years after the grandiose announcement, in a 1962 interview with Advertising Age, Vicary was pressed to admit personally that his study was a gimmick, and a PR stunt. Nevertheless, the concept of subliminal messaging was too fascinating to be disregarded, and by that time it had already been embedded deeper into the cultural consciousness.

In the years that followed, public concerns grew bigger and the situation continued to intensify. While researchers debated the scientific validity of the phenomenon, struggling to produce meaningful results to support the theory, the general public—and especially the media—clung to the idea that hidden messages could bypass rational thought and directly influence behavior.

The 1960s and 70s saw an overwhelming wave of hysteria over the manipulative potential of mass media, which played out in films, tabloid journalism, and the burgeoning field of media criticism. As the cultural focus progressively shifted toward rock music, counterculture, and youth rebellion, subliminal influence was no longer just a tool of Madison Avenue—it was now being linked to moral decline, political subversion, and even malevolent forces from the underworld.

Don't Panic, It Isn't Satanic

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The anxiety around subliminal persuasion took on its most peculiar and diffuse form during the 1980s and 1990s, in what is now remembered as the “Satanic Panic”—a period of widespread cultural delusion, centered primarily in the United States, with its aftershocks trembling parts of Europe. This era was marked by a rapidly spreading, and ultimately unsubstantiated, belief in the existence of an extensive underground network of Satan-worshipping cults. These cults, according to the belief, were responsible for everything from child abduction to ritual sacrifice, with a particular emphasis—of course—on the corruption of the young. Public trials, breathless media coverage, and pseudo-academic reports offered a veneer of credibility, but in time, nearly all of it collapsed under scrutiny. What remained were the unmistakable traces of a classic moral panic, a modern-day witch hunt dressed in the languages of psychology, media theory, and spiritual warfare.

As it happened, the agents of darkness, the alleged proxies of the underworld turned out to be all the usual suspects: artists, musicians, educators. In other words, people whose output into the world can appear ambiguous, with language and communication steeped in poetry, and thus easily prone to being misunderstood or misinterpreted. And all of this, of course, is what naturally attracts highly impressionable young people.

In 1985, against this backdrop of mounting cultural anxiety around youth, music, and moral decay, four politically connected women in Washington—Tipper Gore, Susan Baker, Pam Howar, and Sally Nevius—founded the Parents Music Resource Center (PMRC). The spark emerged when the founder, Gore, reportedly stumbled upon Prince’s Darling Nikki in her daughter’s tape collection. What followed was a full-blown national campaign against what the PMRC labeled “pornographic” or “violent” content in music. Their proposal appeared deceptively sound: label albums, restrict sales to minors, and hold artists accountable for the dangerous messages they were allegedly sneaking into the airwaves.

But beneath its veneer of reason, many artists saw the PMRC’s agenda rather as a soft censorship campaign wrapped in parental concern, animated by a desire to impose a conservative moral code on an increasingly pluralistic, experimental, and chaotic music scene. Televised Senate hearings followed, featuring a motley crew of defenders: Frank Zappa, Dee Snider, and John Denver, who each—in their own way—spoke out against censorship, condescension, and cultural freakout. This antagonizing turned into several years of trials, and public hearings, inspired creative works, and became the reason the iconic "Parental Advisory" label made so many albums so much more desirable by the rebellious youth.

The situation reached a particularly surreal form in 1990 in a courtroom in Reno, Nevada. The British heavy metal band Judas Priest stood trial after being accused of embedding a subliminal command—“do it”—into their song "Better by You, Better Than Me." The claim was that this hidden message had compelled two teenage boys to form a suicide pact. This was a pivotal moment in the era. As the censorship debate reached its peak in the United States and Europe, several important yet nebulous concepts were put to the test: the notions of free speech, artistic expression, as well as the artist's power and social responsibility. Metaphor, fantasy, performance, and sonic intensity were no longer seen as artistic strategies, but weapons, and deliberate acts of psychological sabotage. What the Judas Priest trial and the PMRC hearings earlier manifested was a shared assumption that danger lay not in what was said, but in what might be unsaid, unheard, and yet still somehow able to change you.

The Judas Priest case, just like nearly every other case of a similar nature, was ultimately dismissed due to a lack of evidence. In the years that followed, the fever dream of satanic intervention into the lives of American youths began to subside. When the Cold War was over, the "satanic panic" gradually became a historical footnote, with public attention gradually shifting toward new concerns and anxieties.

That said, the interest in the subliminal persuasion never fully dissipated. Some of it relocated to the domain of culture; we will focus on this idea in a bit. But our scientific understanding of the phenomena also grew, and we should address what we actually know about the phenomenon first—a picture that is far more anticlimactic than it was originally pointed.

Easing The Panic: The Limits Of The Subliminal

So what do we actually know about the nature of subliminal messages and subconscious influence? In essence, subliminal perception is real, and it can, indeed, shape behavior—but only in small, transient, and highly conditional ways. Research in psychology and neuroscience has consistently shown that subliminal cues—such as emotionally charged words, priming images, or quick flashes of faces—can influence decision-making, but only when aligned with existing motivations or mental states.

For example, a study by Strahan, Spencer, and Zanna published in 2002 in the Journal of Experimental Social Psychology, among other things, found that flashing the word “thirst” could make already thirsty participants drink more, but had no effect on those who weren’t thirsty. In a 2011 study on subliminal priming with goal-motivated individuals, researchers Ruijten, Midden, and Ham concluded that subliminal feedback indeed can effectively influence decision-making, but only when individuals are already motivated by a relevant goal. In the experiment, subliminal cues improved performance only among participants primed with a goal, suggesting that subconscious influence depends on active goal-striving.

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Thus it appears that not quite tools of mass manipulation, subliminal stimuli operate rather like nudges in a direction you're already headed. The scale of effect is modest—typically altering reaction times, product preferences, or brief emotional responses, and not blatant implanting commands. For this reason, in modern marketing, deeply committed to strategic integration of behavioral economics and neuroscience, overt emotional framing and algorithmic targeting have largely replaced subliminal suggestion. It is after all easier—and far more reliable—to influence behavior by flooding people with repeated exposure and emotionally resonant narratives than by hiding something sub-momentarily in the corner of a screen.

Although current science generally paints a rather underwhelming picture of the reach of subliminal persuasion, there are some studies that still rock that boat. One, published in 2016 in the Neuroscience of Consciousness journal by Ruch, Züst, and Henke, concluded that, contrary to the belief that subliminal effects are short-lived and negligible, there may actually be a case for long-term subliminal influence on conscious decision-making.

However incomplete our current understanding of the subconscious is, it expresses a vital insight into the nature of attention and awareness. It offers us an opportunity to rethink how much in control we are of our behavior, our independence in the way that we relate to the external environment, our ingrained drive for interaction with the world around us. Rather than thinking of it as a realm of hidden control mechanisms, we can also marvel at the fact that what we call self is highly porous and contingent—we are not programmable automatons, but a complete, unfathomably complex, and highly active system of filters, biases, and emergent impulses, naturally tuned to respond particularly well to what we already want to hear.

Creatively Subliminal

Without a doubt, the notion of subliminal perception, controversial as it is, warped and tattered the social fabric quite a bit, and yet it also inspired an array of creative output. In some cases, like the Suicidal Tendencies song, mentioned in the opening of the article, artists approached the topic from the perspective of cultural criticism. Other creative outbursts of such nature include Frank Zappa's Frank Zappa Meets the Mothers of Prevention (1985), and Dead Kennedys' Frankenchrist (1985). The band Tool paid their irony-filled tribute to the satanic panic era in the song "Die Eier Von Satan" (Ænima, 1994), where grating industrial beat, and screeching textures rub against an intense militaristic German-language spoken word performance, which, although menacing and intimidating in tone, once translated, only reveals a recipe for hash cookies.

Other artists took the idea more literally, treating subliminal messages as a creative tool. Pink Floyd's "Empty Spaces" from The Wall (1979) features a backmasked secret message that, when reversed, reads:

"Hello looker. Congratulations, You have just discovered the secret message. Please send your answer to Old Pink, care of the Funny Farm, Chalfont…"

Artists like Richard D. James (Aphex Twin), and later Aaron Funk (Venetian Snares) took a slightly different approach, famously hiding secret images within the music's sound spectrum, in tracks "Formula" (Windowlicker, 1999) and "Look" (Songs About My Cats, 2001) respectively.

A few acts were even more extensive and deliberate, devising ever subtler ways to interlace subliminal techniques with distinct sonic aesthetics and artistic philosophies. Genesis P-Orridge, the driving force behind iconic experimental bands Throbbing Gristle and Psychic TV, was also a founder of Thee Temple ov Psychick Youth (TOPY) in 1980s—an esoteric network imagined as a radical, anti-authoritarian collective that blended chaos magick, art, and countercultural ideology to promote self-transformation and psychic experimentation outside institutional religion. In many ways, TOPY embodied everything that troubled parents were terrified of—occult rituals, radical music, sexual liberation, and exploration of altered states of consciousness. Needless to say, it wasn't met with enthusiasm by the British government, making the collective a prime target during the satanic panic era witch hunt. Eventually, the pressure from the state was so severe, that most TOPY's activities subsided. But even beyond that, deeply philosophical, the music of P-Orridge was filled with occult influence, with the artist self-admittedly aiming to invoke physical, psychic, and magical responses in listeners—hoping to, in turn, instigate positive change. Viewing language as a powerful tool for both control and liberation, stylistically eclectic compositions often featured layers of cut-up speech, propaganda-like elements, and hypnotically repeating sounds placed intentionally to disrupt familiar patterns of thought.

John Balance and Peter Christopherson of Coil, another ingenious scion of Throbbing Gristle, besides uniquely idiosyncratic approach to electronic music, Like P-Orridge were also deeply affected by Aleister Crowley and occultism. Rather than approaching music simply as entertainment, the duo saw it as a potent psychoactive medium capable of radically transforming the listener. To facilitate this, the band would play with listeners' perception and expectation, often incorporating fragmented and restructured voice samples, chants, echoes of cultural references that sometimes float loudly above the music, and other times buried deeply within its textures.

Scottish electronic duo Boards Of Canada, while tangibly different in the sonic wizardry, also expressed the belief in music's great capacity to alter its listener. In the 2001 interview to XLR8R magazine, Mike Sandison and Marcus Eoin discuss this aspect of their music:

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"I do actually believe that there are powers in music that are almost supernatural. I think you actually manipulate people with music, and that is definitely what we are trying to do. People go on about hypnotizing people with music, or subliminal messages, and we have dabbled in that intentionally. Sometimes that's just a bit of a private joke, just to see what we can sneak into the tracks." (Marcus Eoin)

Besides perfecting the art of evoking nostalgia on demand, the compositions of Boards Of Canada are abundant with hidden messages, enveloped in numerology and psychedelic references. Geogaddi (2002), in particular, has a wealth of playfully hidden subliminal easter eggs. To mention a few examples, “You Could Feel the Sky” features a backmasked voice, that when the track is reversed reveals a phrase: “a god with horns… a god with hooves…” In the middle of the "Dawn Chorus" a whispering voice saying: "you may be dead." The groovy "1969," when played backwards reveals a quote that mentions David Koresh, a leader of the Branch Davidians, an infamous religious cult. Furthermore, the total runtime of the album is 66 minutes, and 6 seconds, and that is not even the half of it.

Practically Subliminal

Alright, now that we've recounted the convoluted history of subliminal audio, it's time to get a bit more practical, and discuss some common methods and techniques. Although the approaches and expressions vary, they all attempt to facilitate the effect—establish presence without awareness. Thus, by their nature, subliminal sounds exist at the threshold of perception—too faint, too fast, or too foreign to be immediately recognized, yet nevertheless effective. Many of the techniques for creating subliminal audio involve some version of the psychoacoustic effect of masking.

We can also get a little meta, and explore psychoacoustic illusions to create subliminal effects. For example the phantom words illusion allows to evoke a sense of a specific word being heard without it actually being present in the signal. To do this, two composites of two-syllable words are looped and sent to each audio channel in a stereo space. Listening to the sounds repeating indefinitely our brains look for familiar patterns, making up a recognizable word.

When it comes to getting subliminal, it is also impossible to overstate the effectiveness of repetition. Uncommon among primates, we humans are surprisingly sensitive to rhythm and repetition. Why do you think that pop tune you heard the other day, still lives in your head rent-free. Dianne Deutsche's speech-to-song illusion discovery underlines this effect, demonstrating that any speech pattern (or any other sound), when continuously repeated, starts to be perceived by us as musical. This is also why chaotic, experimental forms of music that try to break away from the repetition are notoriously difficult to listen to for an accustomed ear, while pop and particularly dance-oriented music rely heavily on repetition to invoke a hypnotic effect.

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Spectral encoding, on the other hand, is a frequency domain process, where the messages are inscribed into the sound through targeted manipulation of specific frequency bands. It can efficiently and sprucely hide sounds above and below our hearing range, or shape the spectrum to encode the data. See the image above: this is a spectral analysis of the spectral encoding audio in the above audio example. As mentioned earlier, Aphex Twin's spectral self-portrait in "Formula" demonstrates a playful use of the method.

Admittedly, the latter two examples bring us already into the realm of steganography, and it would be fair to ask—if the signal is hidden so much that it doesn't even reach our ears, how can it have any influence on us? When it comes to creative purposes specifically, it is important to remember that what we engage with here is not necessarily an exact science, but rather these can be viewed as opportunities to tap into unorthodox ways to engage with the creative work, accent themes and topics we want to explore, sometimes explicitly, but other times wearing a thicker camouflage. A message doesn't have to be made literally out of words, employing subtler aesthetic references—an old familiar melody, the character of the recording, visual imagery—essentially any aspect of the sound that has a certain relevance in the larger socio-cultural context can be carried over to the domain of subliminal. It is the atmosphere, memory- and association-triggering, emotional connection that matter the most.

Conclusion

From Poetzl's flicker experiments to the cryptically nostalgic music of Boards of Canada, the story of subliminal audio reveals less about the potential for brainwashing and more about how, more often than not, feeling takes precedence over thought. The power of music has always resided in that sub-rational space. So whether or not a composition hides a secret message, its very structure operates below the semantic surface, shaping us and modulating our emotions in ways we rarely parse consciously.

Perhaps, then, the ultimate subliminal medium isn’t a backmasked command or a mischievous single-frame flash—but music itself. With rhythm, harmony, melody, drone, and repetition, music offers a uniquely potent framework for transformative influence. Just make sure you use that force for good.