(Investigator 195, 2020 November)
Magnetic tape recording apparatus dates back to the latter part of the
last century. The idea of storing electrical information was expressed
as early as 1888 by Oberlin Smith in an article in The Electrical World.
Although research continued, little was heard by the public of further
developments until 1927, when J. A. O'Neill received the first U.S.
patent for a magnetic tape. The 1960s saw the first audiocassette
recorders on the market, providing a convenient medium for subliminal
Over the past three decades, the sale of subliminal tapes has burgeoned
into a multi-million dollar business. The claims made by promoters
regarding the efficacy of subliminal tapes as therapeutic devices have
not been substantiated however.
Promoters of subliminal tapes claim that by listening to tape
recordings of messages over which a covering sound has been recorded,
the subconscious mind can be influenced in a required direction.
Consideration of how the brain works however, shows this to be false.
Background noises, if they persist long enough, are considered by the
brain to be an irritant and are "edited out". The background noises
used in subliminal tapes such as rainfall, crashing waves and "nature"
sounds, cover a wide frequency spectrum close to what we call "white
noise". After a while the sounds simply become background noise and the
brain starts the editing process. You become less sensitive to noise
and off to sleep you go. Whether or not there is also a message on the
tape is immaterial. If you can't hear it, it won't register.
The applications, according to promoters however, are endless, ranging from losing weight to attracting infinite riches.
The tapes can be listened to at any time during the day or during sleep at night.
The promoters and the products promise short-cuts to success and
instant panaceas for whatever ails one, ranging from giving up bad
habits to building self-confidence, and from improving one's memory
to psychic healing. The result has been an industry whose reputation is
built to a large extent on worthless testimonials and questionable
The sale of subliminal audiotapes in America alone exceeds $50 million annually. One auditory tape sold by Potentials Unlimited actually offers to cure deafness.
The grandiose claims made for the products are such that few people, if
any, bother to enquire what evidence there is, other than personal
testimonials, to support the claims made. Recommendations by those who
have used them are suspect due to psychological pressures making it
difficult to admit that they have been conned.
There are many reasons why users of subliminal tapes are sincere in
their praise. First, there is the desire for self improvement which
motivates the purchase, and an implied commitment to the undertaking.
This can of itself bring about change and become self-fulfilling.
Second, there is the phenomenon known as "effort justification."
Research has shown that the harder we work at something, the more we
like it. Having purchased and utilised a subliminal tape for some time,
most people would justify its use by finding some sort of change in
their lives with which to rationalise the purchase.
There is also the placebo effect — a strong expectation by the tape
user based on the belief that subliminal messages are potent
(Pratkanis, 1992). This misconception was born of a hoax in the 1950s,
when it was claimed that imperceptibly brief insertions in a film
impelled viewers to increase their consumption of popcorn and
Coca-Cola. Cinema runs at 24 frames per second. The countdown numbers
that we see at the beginning of a reel are only one frame and can be
seen clearly. The Coca Cola message which must have been longer would
also have been clearly seen.
In 1958, the Canadian Broadcasting Corporation
conducted a test of subliminal persuasion in which the message "phone
now" was flashed subliminally on the screen 352 times. Telephone
company records indicated no increase in phone calls.
In a study by Greenwald et al (1991), participants were given two
disparate tapes — one containing a subliminal suggestion for improving
memory, the other for enhancing self-esteem. The tapes were
deliberately mixed up so that half the participants received the memory
tape instead of the self esteem tape and vice versa.
After five weeks of daily home listening there was no discernible
change in self-esteem or memory improvement although the participants believed
there was. Pratkanis dubbed this an "illusory placebo effect" — placebo because it was based on expectations, illusory because no
objective improvement occurred.
These results were replicated by Greenwald et al and Auday et al (1991).
Auday, B.C., Mellett, ].L., and Williams, P.M. 1991.
Self-improvement using subliminal self-help audiotapes: Consumer
benefit or consumer fraud? Paper presented to the Western Psychological Ass., San Francisco. Apri11991.
Chirgwin, Richard. 1990. Subliminal sounds, the Skeptic, 10(4):28-9. Australian Skeptics Inc. NSW
Greenwald, A.G., Spangenberg, E.R., Pratkanis, A.R., and Eskenazi, J.
1991. Double-blind tests of subliminal self-help audiotapes. Psychological Science. 2(2):119-122.
Lippman, Susannah. 1994. The Truth About Subliminal Tapes, Earth Star Publishing, Jolimont, 6913.
Pratkanis, AR. 1992. The Cargo-cult science of subliminal persuasion. The Skeptical Inquirer. 16(3):260-272.
_________________ and Greenwald, A.G. 1988. Recent perspectives on unconscious processing: Still no marketing applications. Psychology and Marketing, 5(4):337-353.
From: Edwards, H. 1999 Alternative, Complementary, Holistic & Spiritual Healing, Australian Skeptics Inc.