In 1971, Gilbey's London Dry Gin published an ad in a July edition of Time magazine that caused quite a kerfuffle. The ad depicted a frosty bottle of the gin; set next to it was a tall glass filled with ice cubes, gin, a lime wedge and a stir stick. The issue? The word "sex" was apparently spelled out in the ice cubes. And indeed, once you took a closer look at the cube-filled glass, it certainly appeared to be true. But did Gilbey's do this intentionally, trying to send a subliminal message?
A subliminal message is a type of hidden signal or communication; it's designed to be passed on to recipients at some level that's beneath the normal limits of perception. The message might be recorded backward, a practice called backmasking, or it could be inserted into a frame of film that flashes by so quickly the conscious mind can't perceive it. Or, as in the example above, it could be a word or image hidden within an ad [source: Merikle].
Subliminal messages work similarly to hypnosis or auto-suggestion in that they're perceived outside the conscious realm, by the unconscious or deeper mind. So you don't consciously know you're being sent a message, yet a deeper level of your brain is taking it in [source: Dobson].
Many people fear that advertisers, politicians and other manipulative types may try to influence them through such messaging. Their fear stems from the fact that it's the conscious mind that critiques messages, and an unconscious mind, which picks up subliminal cues, would be unable to fend off these suggestions. Perhaps because of this, governments from Canada, Australia, the U.K. and the U.S. prohibit the practice [sources: Dobson, Subliminal Messaging].
Yet when you think about it, people are constantly being manipulated in all sorts of ways by advertisers. If a movie star is repeatedly reaching into a bag of Lay's potato chips during a movie that might make some people want to do the same without realizing why. Is that a subliminal message? And if so, is this form of subliminal messaging just as nefarious as flashing the words "Eat Lay's potato chips!" across the screen so quickly we don't consciously perceive it? And would either really work? Let's dig into the subject a bit, starting with the history of subliminal messages.