For a lot of the people who know me or read my stuff, I have a sort of reputation as a debunker. A big part of my activity involves discovering and promoting some ideas for personal development and improving people skills, another big part involves showing the flaws in other ideas, to facilitate effective growth.

I believe there are a tone of people skills and personal development ideas out there, most of which only generate marginal improvements, and this is why I think debunking some can be as important as supporting others.

Today, my focus is on debunking subliminal tapes. And I’m going to use for this an excerpt from the book “Psychological Foundations of Success” by Dr. Stephen Kraus, a Harvard-trained scientist and a business consultant. I think his words do the debunking better than mine ever could.

Let’s consider an example of success snake oil: subliminal self-help tapes. These tapes are a multi-million dollar business, and it is easy to see why. Their promise of easy, effortless change is a marketer’s dream. Simply listen to the tapes, we are told, and although the subliminal messages in them can’t be heard audibly, they tap the power of the subconscious mind to bring about massive change and success. If you want to lose weight, for example, there’s no need for the inconvenience of exercise or the sacrifices involved with healthy eating – simply listen to the tapes and pounds will melt away. And losing weight is just one example – other tapes promise to boost self-esteem, improve memory, increase worker productivity, and even aid in the recovery from sexual abuse. There’s only one problem: they don’t work.3 If it sounds too good to be true, then it probably is – and effortless change via subliminal tapes is indeed too good to be true. Every independent scientific study has reached the same conclusion – these tapes are a waste of money. […]

Despite numerous studies demonstrating that subliminal tapes are worthless, people continue buying them in large numbers. The problem is that manufacturers of these products have become experts at deceptive marketing, and they conveniently ignore the carefully-conducted studies demonstrating the ineffectiveness of the tapes. As Anthony Pratkanis put it, “Tape company representatives are likely to provide you with a rather lengthy list of ‘studies’ demonstrating their claims. Don’t be fooled. The studies on these lists fall into two camps – those done by the tape companies and for which full write-ups are often not available, and those that have titles that sound as if they apply to subliminal influence, but really don’t.”

These deceptive marketers often point to one study in particular, known to many as the “Eat Popcorn/Drink Coke” study. Conducted in the late 1950s, this study flashed the messages “Eat Popcorn” and “Drink Coke” briefly on a movie screen. Thousands of moviegoers were supposedly exposed to these messages over the course of six weeks, and the result was reportedly an increase in Coke sales of 18% and in popcorn sales of nearly 58%. Reports of the study fueled international outrage – several countries outlawed subliminal advertising, and the Federal Communications Commission threatened to strip the broadcast license of anyone using subliminal advertising. Amidst this well-publicized furor, a much quieter development was unfolding. Researchers throughout the world were trying – and failing – to replicate the dramatic findings of the Eat Popcorn/Drink Coke study. A Canadian television show, for example, flashed the subliminal message “Phone Now” during its regular airing. Not only was there no increase in phone calls, but when viewers were asked to guess what the message had been, none of the 500 who guessed did so correctly (interestingly, nearly half reported feeling hungry or thirsty, demonstrating not the power of subliminal persuasion, but rather the power of suggestion – those familiar with the Eat Popcorn/Drink Coke study experienced what they expected to experience). This and other failures to replicate the original never got the widespread publicity of the initial study. The media sells stories, and the story that marketers are manipulating our unconscious minds sells well, whereas a story of carefully-conducted research failing to confirm the initial results is decidedly less sexy.

Here’s another fact that didn’t get much publicity: James Vicary, the author of the initial study, admitted in 1962 that he had simply made up the results to attract customers for his failing marketing business. Regardless, this “study” and others like it, fueled by a growing distrust of advertisers, became ingrained in American popular culture. By the early 1980s, more than four-in-five Americans had heard of subliminal advertising, and of those, two-in-three believed it could be effective in selling products. By the 1990s, $50 million a year or more were being spent annually on subliminal success products, despite a total lack of compelling evidence that they work.

How’s this for real personal development science?