Subliminal Influence and NLP
What is a Subliminal Influence ?
The first thing we need to do is to establish what exactly we are talking about, and why it is worth examining.
What Do We Mean When We Say Something is "Subliminal ?"
The term subliminal technically means below the threshold of perception, but this definition is not actually used in practice, because most experts in perceptual psychology and in cognitive science agree that information that is truly below the limen of perception (e.g. too soft, too distant, too faint) is simply not perceived reliably in any way. That is, if the stimulus strength is too weak to become the focus of attention, it is also too weak to activate any unconscious processes. The loophole in this concept is that we can envision classes of stimuli which are above the basic stimulus threshold for perception, but escape notice for other reasons.
A more practical working definition of a subliminal influence that captures the spirit of the way the term is commonly used would be information that influences our behavior without our being consciously aware of this influence. That is, the term is used to mean that we can "unconsciously" understand and act upon a message that we don't notice we have received. This implies some particular way of determining that we have been influenced by the message.
The popular use of the term subliminal often implies messages that we can perceive but don't perceive. An example of this would be messages that we aren't directly attending, such as in the experimental model of dichotic listening, where we hear different messages in each ear and try to listen to only one of them. In theory, the message that we are not directly attending is heard "subliminally." Another example would be a visible message hidden within a larger pattern. This includes such cases as the infamous claims made in the 1970's by various authors that advertisers were hiding sexual images in mundane pictures in order to secretly titillate the viewer and thus influence their state of mind toward the product. Most of the practices used in neurolinguistic programming and in hypnosis in general either provide messages that we are fully conscious of perceiving, or provide messages that we could perceive, but are not directly attending.
The term subliminal can also imply a message and that we cannot consciously perceive at all, such as the experimental model of tachistoscopic images which are seemingly flashed too rapidly to be recognized consciously. If the claims of audio self-help "subliminal" tape manufacturers are accurate, then there are also audio methods of encoding messages that are not consciously perceived, such as by modulating music patterns by the frequency or amplitude of vocal patterns. There is nothing subliminal in this sense in the classical model of hypnosis, nor in the typical practices of neurolinguistic programming.
Defining "subliminal" for experimental purposes
Subliminal perception refers to apparent perception that occurs according to some sort of test of subthreshold levels or "unconscious" types of sensory stimuli. The sensory threshold may be experimentally defined in either of two ways, subjectively (the intensity or stimulus type below which someone does not report the presence of the stimuli, or reports it less than half the time) or objectively (below which they cannot detect the presence of the stimuli, or they detect it less than half the time). What is the difference between reporting and detecting ? In the subjective measure of threshold, reporting, the subject is asked whether they are aware of a stimulus. In the objective measure of threshold, detection, the observer is asked to distinguish between multiple stimuli presented successively. This objective method defines awareness as the ability to discriminate between alternatives in a forced-choice test. Subthreshold stimuli are reported or detected less than half the time (or not at all).
Recent studies indicate that subliminal perception is probably best viewed as perception in the absence of concurrent phenomenal experience. (Cheesman & Merikle, 1986) This is as opposed to the mistaken notion of perception in absence of a detectable signal. The former is directly applicable to hypnosis, while the latter is more applicable to the questionable business of subliminal persuasion technologies.
The typical test of subliminal perception involves a picture or word flashed for a very brief period by means of a tachistoscope. The stimuli are considered subthreshold or subliminal because the subject generally cannot report with accuracy (above chance levels) whether a message is being flashed or a blank screen is being shown. The effects of subliminal perception are tested by means of having the subject perform a task that can be influenced by the subthreshold stimulus. If this influence occurs reliably, then there is considered to be evidence that information can be processed without conscious awareness. The two important questions about this are then (1) under what conditions and with what kind of information and processing this occurs, if it occurs at all, and (2) how the information perceived compares with information received under other conditions (that is, does being received subliminally have any special significance).
What Is Supposed to be Special About Subliminal Influences ?
In order for a subliminal influence to be interesting, it must have an effect upon us that we don't find from more straightforward influences. If it were simply an information transfer that we were talking about, which we later processed consciously without knowing where it came from, there would be little interesting about it. It would simply be neutral information that whose source we did not remember. The theoretical position that makes subliminal influence worth considering is that messages received outside of awareness are ostensibly received and understood but processed very differently than the usual.
Various forms of supposed subliminal influence are often claimed to be ways of bypassing our critical intelligence in order to "reprogram" our mind without realizing what is happening. Several widespread fallacies have made this idea seem more plausible than it should, even among the knowledgeable, but it is based on a very weak foundation scientifically. This in itself of course does not mean that it doesn't happen, only that dramatic claims about this process should be viewed skeptically, particularly if they borrow the veneer of scientific research.
The type of subliminal influence we might hypothesize in hypnosis or neurolinguistic programming is more closely related to the subtle influences of human nonverbal communication than to the idea of hidden messages that reprogram the mind.
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© 1993-2008, by Stever Robbins