By Mark Leary, Ph.D., Duke University
We know that subliminal stimuli can affect people’s thoughts, emotions, and behaviors. But can audio stimuli significantly affect human behavior?
Subliminal Stimuli and Conscious Awareness
Many people are surprised to learn that subliminal stimuli can affect us at all. But it shouldn’t be surprising. The brain does not usually care whether a piece of information is received subliminally or received in conscious awareness. If the stimulus or the information gets to the brain, it’s in there. Whether you happened to be consciously aware of it is beside the point.
After all, computers and cell phones and video games react to all kinds of stimuli. When you touch the screen on your cell phone it reacts to the input and makes complex decisions without the necessary ‘awareness’. When a voice-activated computer responds to verbal commands, it is presumably not consciously aware of the words that it ‘hears’.
So, clearly, conscious awareness isn’t necessary in order for a computer—or for a human being—to respond to its environment.
This is a transcript from the video series Understanding the Mysteries of Human Behavior. Watch it now, Wondrium.
Subliminal Priming and Its Relation to Relevant Goals
Let us take a quick look at what is known about subliminal priming. A recent study showed that subliminal priming will affect people’s behavior only if the subliminal stimulus is relevant to a goal that the person already has.
Think of James Vicary, the researcher who claimed to have increased sales of Coke and popcorn through subliminal visual messages. But no one else has been able to do what he claimed. One reason may be that subliminal stimuli affect behavior only when people already have a relevant goal.
This means that if you’re not thirsty, subliminal messages aren’t going to cause you to go get a Coke. But if you’re already thirsty, a subliminal message might influence your choice of drink.
Two researchers recently demonstrated this effect. They subliminally presented participants with the name of a specific brand of iced tea. The subliminal presentation of the brand name led participants to prefer that brand, but only if they were already thirsty. So, subliminal messages can guide the direction of people’s judgments, but only if they are already motivated to do something.
Learn more about why self-control is so hard.
Subliminal Audio and the Self-Help Industry
Subliminal stimuli are usually visual—pictures or words that occur too quickly to be processed consciously. But we can also have subliminal audio stimuli—sound waves that cannot be heard consciously.
That’s the basis of the 50-million-dollar industry that makes self-help audio-recordings that contain subliminal messages. There are recorded programs to help people lose weight, improve memory, enhance self-esteem, and help people in other ways using subliminal audio messages that are embedded either in music or in relaxing sounds such as white noise or ocean surf.
Several controlled experiments have been conducted to test the effectiveness of subliminal recordings in helping people with various problems. Those studies uniformly fail to find any evidence that audio programs containing subliminal suggestions are effective.
Testing the Efficacy of Audio Recordings
One of these studies tested whether audio recordings that were advertised to increase people’s self-esteem and to increase their memory are effective. The researchers tested the research participants’ memory and self-esteem and then randomly assigned them to listen to the recordings every day for five weeks.
The recordings themselves were actual programs containing subliminal messages that are sold to help with self-esteem or with memory. The results revealed no evidence whatsoever that the recordings improved people’s memory or self-esteem after five weeks of use.
Learn more about if subliminal messages affect behavior.
Three Reasons Why Audio Messages May Not Work
There are probably several reasons why recorded subliminal messages don’t help people. First, research suggests that, to influence emotions or behavior, information in subliminal messages must be very simple—only a couple of words at most. But these self-help kinds of recordings usually have entire sentences, such as “I have high worth and high self-esteem.”
Second, the subliminal messages can be literally covered up by the music or background noise. The brain must be able to separate the message from the other sounds. There is no evidence that it can separate the subliminal audio track from the louder music or background noise in these kinds of recordings.
And finally, there’s nothing that says that every message that the brain gets will have its intended effect. Does the message “I have high self-esteem” really cause people’s self-esteem to go up? Do messages about memory actually make people remember better?
The Inefficacy of Complex Messaging
Research suggests that subliminal stimuli that are presented visually are more likely to affect behavior than auditory subliminal messages. There are now companies that make devices that present self-help messages subliminally on your TV set. So, you can get subliminal messages that supposedly help with your weight or stress or self-esteem or memory while you watch normal television shows.
The effectiveness of these subliminal devices has not been adequately tested, but most evidence would suggest that trying to present complex messages subliminally doesn’t work.
Common Questions about Subliminal Audio Stimuli
Subliminal messages are the most effective when they match a goal the person already has. For instance, you can be influenced to go and buy a specific brand of soda only if you are already thirsty.
Research shows that the brain will respond to a message that is received, even if the person is not consciously aware of the message. This is how subliminal messaging works.
The self-help industry uses audio messaging as a tool to help people lose weight, improve memory, enhance self-esteem, and help people in other ways. This industry uses subliminal audio messages that are embedded either in music or in relaxing sounds such as white noise or ocean surf.
Subliminal messages which are very simple—not more than a word or two—and are visual rather than auditory messages, have been seen to be more effective than others.
