Created: 4/1/1958

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A collection ol articles on the historical, operational, doctrinal, and theoretical aspects ot intelligence.

All statements of fact, opinion or analysis expressed in Studies in Intelligence are those of

ihe authors. They do not necessarily reflect official positions or views of the Central Intelligence Agency or any other US Government entity, past or present. Nothing in the contents should be construed as asserting or implying US Government endorsement of an article's factual statements and interpretations.


Perception is demonstrated to have occurred below the threshold of conscious sensory experienceerson re-spondstimulus too weak in intensity or too short Infor him to be aware of it Individual behavior without awareness of the stimulus, of which subliminal perceptionubtype, hasubject of study In psychologicalfor at leastears,reat deal of technical data has been collected on the subject. Recently it has beenwith some theories of depth analysis and popularized for possible commercial exploitation by the advertising world.

In the most sensational of these popularized experiments, an Increase In popcorn salesew Jersey movie theater is said to have been stimulated by subliminal interruptions of the feature film with an advertisement urging the patrons to buy popcorn. The exposure timemall fractionecond, was too brief for conscious discrimination by an observerIn the film story but presumably long enough to have some stimulating effect. The advertising men who arcinterested In this phenomenonales technique argue that tbe short-duration stimulus appealsositive motive, for example an appetite for popcorn, without arousing the rational, conscious sales-resistance of the Individual, basedon the desire to save money or lose weight.

The argument becomes more complicated with respectroduct which there is no specific preexisting positiveto acquire. The appeal Is now said to be directednderlying motive presumed to be always Operating, never sati-atexLaay the sexhe ma^^

pect of this ubiquitous rive which can hardly be * :

directly satiated in polite society and one of which the coiv

BciouB recognition is more or less anxiety-producing. Tha '

vague discomfort the individual feelsesult of^ *

attarulation must be allayed by some associated gratification,

and this gratificationadvertiserthe socially

Subliminal Perception

acceptable acqulslUoti ol tbe product which he Is trying to 'A-

It Is evident that there are several mighty leaps in logic in the advertising man's argument,reat many places where his scheme can go astray. He has taken severalphenomena which have been demonstratedimited degree in controlled laboratory experiments and strung them together into an appealing argumenttechnique,"part of what he Is promoting Is supported by laboratory data, however, it has enough status to warrant serious

The operational potential oi other techniques forerson topecific controlled action without his being aware of the stimulus, or the source of stimulation, has in the past caught the attention of imaginative intelligence officers. Interest in the operational potential of subliminal perception has precedent in serious consideration of the techniques ofextrasensory perception, and various forms ofBy each of these techniques, it has been demonstrated, certain individuals can at certain times and under certainbe influenced to act abnormally withoutof the influence or at least without antagonism-After careful research on each of these methods, however, it has become apparent that although they occasionallydramatic results, their lack of reliability and tbelrfor extremely precise controls to obtain the desired effect have limited their operational utilityery few verywhere Just the right persons can be put together at Just the right moment under closely controlled circumstances. The primary danger observed in connection with this unreliability Is thatf inadvertently producing Just the opposite effect to that desired. Subliminal perceptionractical control or persuasionis prone to the same difficulties. .'

There are four principal categories of behavior

The Individual may be unawarehis behavior

He may be whispering without realizing he isor he may be movingrap without knowing that

Subliminal Perception

ihe trap ispecial case here Is abnormalin which the individual falls to realize what he is doing because his normal awareness and self-control have been interrupted by disturbing agents such as fear,illness, drugs, or hypnotic suggestion.

relation of his behavior to some stimulus.

The Individual may be unaware of the fact that hisis Influencing him by saying "Right" afterstatements and by remaining noncommittal after others. The process called "operant conditioning" falls into this category.

stimulus Itself, because of its slight impact.

The individual may be unawareery faint sounduick flash of light, unaware in the sense that he lacks the usual visual sensations. Subliminal perception fails Into this category.

precise nature of the stimulus, as well as itshis behavior, because of inattention.

The individual may be aware of vague sensations, but he Is not aware either of the source or of the significant content of the stimulation, although his behavior may change hi accordance with changes In the stimulus. This categoryreat deal of perceptual activityordinary socialerson is often unaware of the specific cues and clues to which he Is reacting notthe stimulus is Insufficient to reach thebut because the effort to be fully aware of all the cues all the time would create tooognitive strain. Inerson to do something he normally orwould resist doing an Intelligence operative can make use of any one of these categories of psychological processes. Usually the purpose is to produce behavior of which theIs unaware. The use of subliminal perception, on the other hand,evice to keep him unaware of the source of hisThe desire here is not to keep htm unaware of what be Is doing, but rather to keep him unaware of why he is doing It, by mashing the external cue or message with subliminal presentation and so stimulating an unrecognized motive.

In order to develop the srrhllmlrtal perception process for naeeliable operational technique, it would be necessary a) to

Subliminal Perception

define the compositionublirnlnal cue or message which

will trigger an appropriate preexisting motive, b) to determine

the limits of intensity between which this stimulus Is eft*ectire

but not consciously perceived, c) to determine what

Ing motive will produce the desired abnormal action and under

what conditions it Is operative, and d) to overcome the defenses

aroused by consciousness of the action itself.

As to the composition of the subhminal cue, it cannot bethat Just any message presented close below theof recognition will be translated Into appropriate action. The determination of tbe right kind of message in terms ofnumber and type of words or symbols, grouping ofand so forth has been the objectreat deal ofexperiment. Thereood deal of loreew rather vague principles available, but generally they concern rather trivial areas of action from the viewpoint of theoperative. Since the effectiveness of the procedureon not arousing the person's defense mechanisms, and since defense mechanisms are not only peculiar to eachbut hard to discover, it Is difficult to specify even what is to be avoided In the composition of the subliminal cue In order not to arouse the defenses.

Thresholds of recognition are variable and difficult to If the Intensity of the stimulus is much below anthreshold it doesn't get through to even theareas of his sensorlum. But recognitiontremendously, not only among individuals, but also inindividual from one time to another, in accordancephysical situation, his physiological condition, and abovedegree to which he is psychologically attuned to thecontent of theormal human being ismore complex receiving instrument than anygadget, andtimulus forariabledifficult. In most of the laboratory studies on whichcurrent theory of suburnlnal perception ishere has "ong pretrial period requiring the subject's full coopcra- - to zero him In on the subliminal signal. Such

Is clearly not feasible for operational use. The message must

> For specifications and data sea "Handbook oftereai... v .

Subliminal Perception

therefore be transmitteduch wider intensity band and may frequently not get through or may on the other handto the subject's consciousness and arouse his defenses.

The message once received is presumed to trigger somesubconscious motivation to action. There are numerous psychological theories about such inner functions, but little definitely known about them.omewhat homogeneous sample of people Isumber of times, most of them will be sensitive most of the time to the subuminal cue; but some individuals,reat variety of reasons we can little more than guess at, will be Insensitive. In this minority of instances the individual may do nothing, may do something trivial Rnd irrelevant, or may do the exact opposite of what was intended.

If the subliminal cue is to work by tripping off an existing motive to action, one must know what motives are positive and operant at the moment. The obvious basic drives. hunger, sex) are sometimes satiated and sometimes subordinated.reat deal of knowledge about the individual, somecan be attained, but it isatter ofThe percentage of instances will be high where themotive to that desired will be tripped on*.

There appears thus to beyriad of factors that even the most simplified empirical tests carried out with the best possible cooperation of the subjects are rarely marked by really significant reliability. Furthermore, witharge number of variables and relatively low reliability, it is difficult to deter-rnine whether the controlled variable or uncontrolled artifacts are producing whatever results one does observe.

Finally, the subliminal device to avoid alerting andefenses by masking the cue and the basic motive does not cover the effect of awareness of the resultant abnormal action itself, with its Implications and consequences. Assuming that one could persuade to such action byue sub-lirrilnally, there is no way of effecting the action withoutand without tripping off defenses and rational resistance: It must be concluded that there are so many elusive variables and so many sources of irregularity In the device of directing subliminal messagesarget Individual that its operational feasibility Is exceedingly limited.

Original document.

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