Patent No. 6292688 Method and apparatus for analyzing neurological response to emotion-inducing stimuli

 

Patent No. 6292688

Method and apparatus for analyzing neurological response to emotion-inducing stimuli (Patton, Sep 18, 2001)

Abstract

A method of determining the extent of the emotional response of a test subject to stimului having a time-varying visual content, for example, an advertising presentation. The test subject is positioned to observe the presentation for a given duration, and a path of communication is established between the subject and a brain wave detector/analyzer. The intensity component of each of at least two different brain wave frequencies is measured during the exposure, and each frequency is associated with a particular emotion. While the subject views the presentation, periodic variations in the intensity component of the brain waves of each of the particular frequencies selected is measured. The change rates in the intensity at regular periods during the duration are also measured. The intensity change rates are then used to construct a graph of plural coordinate points, and these coordinate points graphically establish the composite emotional reaction of the subject as the presentation continues.

Notes:

BACKGROUND OF THE INVENTION

The present invention relates generally to methods and apparatus for neurological testing, and more particularly, to methods and apparatus for determining the emotional state of an individual over the period of time during which that individual is being exposed to time-varying stimuli. While in one respect the invention applies to determining the neurological, psychological, or emotional response of an individual to test stimuli, in many instances, the invention is applicable to using individuals to test a program containing certain stimuli, in order to determine whether such a program will subsequently create favorable responses in other individuals of similar sociocultural-economic makeup.

One of the most practical applications of the method and apparatus with which the invention is presently concerned is that of consumer response testing. Accordingly, this aspect of the method will be discussed immediately herein, while a discussion of other applications and purposes implicit in the invention will be set out elsewhere herein.

In the United States, and elsewhere throughout the world, advertising is heavily used to promote consumer, commercial and industrial products. It is almost universally accepted that, as between or among products which are generally similar to one another in content, price, or quality, successful advertising can help a particular product achieve much greater market penetration and financial success than an otherwise similar product. Advertising, and particularly consumer advertising, although a multi-billion dollar industry in the United States alone, is an area wherein workers find it extremely difficult to create and reproduce what prove to be consistently successful advertising campaigns, themes, or other materials. It is likewise accepted that while it is often easy to predict that response to a particular proposed advertisement or campaign will be unfavorable, it is not known how to create individual advertisements and/or campaigns which can virtually be assured of success on a consistent basis.

Moreover, while it is not always difficult to discover how to make advertising which may simply interest or amuse potential consumers, or to create advertising that consumers will remember, it is often quite another thing to create an advertisement or campaign which succeeds in actually motivating potential consumers to become actual consumers. There are numberless instances known to the advertising community wherein advertising for a particular product is well recognized, is associated with the product and creates a lasting and favorable impression on the consumer as regards the manner in which the advertisement is presented. Yet, as far as can be accurately measured, many such ads fail to impel viewers to use more of such product, or favor it over that of a competitor.

The advertising industry has also recognized that an advertisement must serve the functions referred to above and that this is normally done in individual stages. Thus, the agencies realize that the creative message must attract the user in some way, and preferably, convey a message or impression about the product as well as contain a command or "call to action." However, the particular emotion required to secure attention may defeat the purpose of the message or compromise the call to action portion. Likewise, a part of the message, in an attempt to be clever, may offend some viewers or, in an attempt to gain attention, may appear more frivolous than intended.

Hence, it is very difficult on a prospective basis to predict whether a viewer will see a commercial as imaginative and clever on the one hand or frivolous and incredible on the other, when the differences in such presentation are very slight. Similarly, an overly detailed message may appear to be too clinical or perhaps worse, condescending, while another message may be non-offensive but also non-informing. The differences in comprehensional and emotional states of advertising material viewers may be slight but extremely important.

Hence, among all the possible advertisements that might be produced in the hopes of generating a successful consumer response, even where a large number of efforts are summarily dismissed or weeded out, the persons preparing the advertising and the companies using the advertising for promotional purposes simply cannot be sure within narrow limits as to whether particular advertising material will be a success in the marketplace. Accordingly, it is common to find that long after decisions are made and expenditures incurred in pursuit of presenting a particular advertisement (or theme or campaign of advertisements), that such efforts have simply not been successful, in that the campaign failed to produce sales in amounts proportionate to the expenditure of effort and money.

It is believed that an ideal advertisement is one which can be comprehended by the viewer or listener, which contains an inherently credible message, and which contains an imperative or call to action which will stimulate the viewer or listener to purchase the product in question. The advertising industry has for decades accepted the principle that a simple presentation of an advertising message in cold, hard, clear and logical terms is usually insufficient to induce a prospective purchaser to buy a particular product.

Even if viewers were highly analytical, (and it is accepted that most consumers are not), there is still the problem of differentiation between products whose characteristics are either highly subjective or whose quantitative differences are very minute vis-a-vis those of a competitor. Thus, the flavor of a beer or a hamburger, or the appearance of an article of clothing, is simply incapable of being quantified and presented in analytical terms. Even if such were the case, the question of motivation to buy a selected product would still remain.

Consequently, it has come to be accepted that in a great majority of cases, with a few possible exceptions not pertinent here, the decision to buy products is an emotional one in one sense or another. The presence of such emotion does not imply that the choice is irrational, but merely that it meets a need that the subject perceives himself to have, or will have, at the time of purchase. Whether the emotional response is one of self-satisfaction, one of belief that an intelligent choice has been made or that the choice will create a favorable appearance, image or other response in the buyer is not particularly important. According to the invention, it is believed that discovering and qualitatively and quantitatively analyzing the actual emotional response of a subject is the key to correlation between an advertising presentation and a successful sale of the product.

Referring again to the subject of advertising response, it would be ideal if people preparing advertisements were able to put themselves in the shoes, so to speak, of the particular customer. However, while certain advertising agencies are able to use the talents of creative personnel who are successful more often than not, a high degree of correspondence between choosing and presenting a particular ad and achieving product sales is simply not available on a consistent basis.

Of course, for many years, efforts have been made to determine consumer reactions or consumer response to advertising by different methods of obtaining "feedback." These include many forms of interviewing or testing consumers, either individually or in groups. Programs which are commonly used consist of "focus groups" made up of subjects who are shown different materials and asked about their response to the materials. Other programs comprise telephone interviews with members of a selected group or universe. These efforts continue, but the results they obtain are often questionable in terms of value to the advertiser.

The industry, having accepted that the word of a person creating an ad is insufficient to insure success, and knowing that a product proprietor does not consistently hold the key to identifying and pursuing advertising successes, has relied significantly on focus groups and questionnaires, those research techniques, including the use of reaction surveys, which are now in common use.

The answers of persons who are questioned during response testing, however, are notoriously unreliable as an indicator of their true emotions. For years, workers in the field have realized that, for any number of reasons, test subjects tend not to recall, or to be indirect, evasive or simply inaccurate in describing their emotional response to a particular stimulus. Thus, even if these subjects were able to recall accurately their emotional state at the time of perceiving stimuli, the likelihood that they could recall and identify an exact emotional state or set of feelings, particularly where the emotions change rapidly, is very unlikely.

This is thought to be attributable to a number of causes, including inadequate vocabulary and possible protection of the ego of the test subject vis-a-vis the tester. Thus, many test subjects are reluctant to disclose that they are more emotional than seems prudent, particularly when disclosing such an emotional state to a virtual stranger. More important than the vagaries of recollection and characterization of emotions at a particular time is the comparatively recent realization that during an advertising presentation, (for example, a television commercial lasting 15 to 30 seconds), the subject undergoes a large number of emotional state changes. Therefore, asking the test subject to recall each such state and its comparative intensity is simply asking the impossible.

According to the present invention, tests have shown that a subject might undergo as many as 5, 10 or even 15 changes in emotional response while watching a commercial that lasts only 15 to 30 seconds. Because emotional states vary, and change with great rapidity in intensity and/or polarity, (or simply disappear altogether), it has been realized that a higher quality of emotional states analysis is required for response testing to achieve maximum effectiveness.

According to the present invention, it is believed that if a second-by-second recording could be made of the emotional state of a viewer of a television commercial, and if it could be shown how such emotional changes correspond to the exact subject being presented at any one increment of time, successful or improved commercials could be created with regularity. Thus, and referring to the previous discussion, if a particular subject were to report that he were "turned off" by a particular commercial, then a worker might consider that the commercial was a failure. However, it is at least possible if not likely that certain features of that exact same commercial might have had strong attraction for the viewer, and it was another aspect or portion of that same commercial that "turned off" the subject. If this were actually the case, then the attractive parts of any given presentation could be retained and unsatisfactory portions could be eliminated or modified. By the same token, subject matter creating a strong positive response could be utilized to the greatest possible extent and could be repeated and/or incorporated in other materials.

It has been established through medical research, including that carried out by the Naval Aerospace Medical Research Laboratory, that EEG recordings reflect the fact and manner of information processing by an individual in a general or global sense. Thoughts, feelings, perceptions, and instructions all are processed in the brain as information, the reflection of which processing is detectable using EEG methods.

According to now accepted principles, the electrical activity incident to brain function can be detected and measured. Electroencephalography ("EEG") is the science of measuring brain waves. Using research information which correlates brain wave activity of a particular frequency and character to a particular emotion makes it possible to discriminate among polar opposite emotions as well as closely allied emotions. In the present context, the primary emotions (and their polar opposites) with which the invention is concerned are those of pleasure, arousal, dominance, abstract comprehension and pictorial comprehension.

The emotion of pleasure is self-explanatory and relates to enjoyment of what is being perceived. Abstract and pictorial comprehension are essentially self-explanatory. Arousal refers to an awakening of interest in the subject matter and dominance, or its polar opposite, submissiveness, refers to receptivity or openness to ideas or suggestions. Thus, a person whose emotions are in a dominant state is not open to suggestion, and a person in a low state of arousal lacks interest in an idea.

Referring to the mechanics of measuring emotion, the invention utilizes what is termed a circumplex model for correlating neurophysiological manifestations to emotions. The circumplex model has a pair of orthogonal axes intersecting at an origin. The emotions are displayed as points arranged in a circle about the origin, with diametrically opposed points representing polar opposite emotions and adjacently displayed points representing emotions that differ from each other more by shading than by character. Graphs are made by plotting positions on the circumplex and the character of the subject emotion is established by mathematical modeling ("non-linear analysis") based on brain wave frequency and intensity.

Inasmuch as an important aspect of the invention concerns the emotional changes undergone by the subject in response to presentation and detection of stimuli, the graphical or mathematical models are utilized to establish emotional conditions at various times and track the history of the emotional changes in relation to the stimuli. These methods then enable a comparison to be made between presented subject matter and a true, objective emotional response in the test subject. In general, this "non-linear dynamic" method establishes the relationship or linkage between EEG data and brain function, and hence, emotion. Research workers can convert data taken during observation of stimuli by a subject into an accurate, second-by-second record of the emotional response of the test subject to the stimuli being presented. While the manner of analysis will be described in greater detail, the invention has been successfully practiced by measuring the amplitudes of EEG waves at up to five individual frequencies, including 8 Hz (cycles per second), 13 Hz, 16 Hz, 18 Hz and 26 Hz. At each given frequency, the amplitude of the signal is indicative of the strength of a particular emotional component.

Comparing the values of a given component on one scale to the value of a component taken on another scale enables the tester to establish an accurate, all-around emotional state at a given instant. The general state determined by comparing two values is then refined into an exact emotional profile using comparisons of other values as auxiliary or follow-on steps. The invention holds out the promise of correlating these measurements of emotional intensity and characterization to a series of exactly defined emotions and, equally important, the changes and change rates in these emotions as the subject is exposed to stimuli, typically one or more audio-visual presentations. These changes and rates are sometimes called "composite emotional forces."

In view of the failure of the prior art to provide an effective method of determining the emotional response of a test subject of the content of time-varying stimuli, it is an object of the present invention to provide a method and apparatus for this purpose.

Another object of the invention is to provide a test method which will enable a correlation to be established between the actual emotional state of a subject being measured and the content of a message or other stimulus being presented to the subject at any given time interval within the presentation.

Yet another object of the invention is to provide an improved method and apparatus for analyzing the effectiveness of actual or proposed advertising copy or other presentational material.

A further object of the invention is to provide a method for enabling emotions and emotional changes and change rates in a test subject to be determined by directly measuring several components of the emotion and plotting the components to characterize the emotion in an accurate way.

A still further object of the invention is to provide a method of charting a sequence of emotional response signals in graphically visible form so as to facilitate analysis of an overall emotional response to predetermined stimuli.

An additional object of the invention is to provide a method of classifying the acceptability of advertising content by predetermining its emotional impact on test subjects before determining the final form which such advertising will take.

Another object of the invention is to utilize a method of direct testing of emotional components in selected individuals as a way of measuring the anticipated response to a given advertisement by individuals in the general population, and hence to greatly increase the predictability that such advertisements will succeed.

Yet another object of the invention is to provide a method that will minimize or eliminate waste of advertising by preventing advertisers from presenting ads that are unlikely to succeed, based on predictions using direct emotional response test subjects.

A further object of the invention is to provide a series of correlational tools to associate individual emotional response components, both in character and intensity, with particular brain wave activities for the purpose of accurate emotional response testing.

The invention achieves the foregoing and other objects and advantages by positioning a test subject to observe the selected stimuli for a given duration, establishing a path of communication between the subject and a brain wave detector/analyzer, determining at least two frequencies at which brain waves corresponding to particular emotional component intended to be analyzed are generated, presenting stimuli to a test subject, recording the amplitudes of brain waves at particular frequencies and thereafter comparing the amplitude changes in the different brain wave frequency bands, over the duration of the presentation, and thereby determining the overall and particular emotional responses of the test subject to one or more of the various individual portions of the presentation containing the stimuli.

The invention also achieves its objects and advantages by providing a method of emotional analysis that includes determining which one or more emotional scales are important to the subject matter of a test or other analysis, determining the brain wave frequencies which characterize such one or more emotional scales and wherein the brain waves vary in intensity in relation to the degree of emotional response of a subject to input stimuli in the form of a given presentation, exposing the subject to a presentation having a particular, predetermined content, noting the ongoing variations in intensity of the brain waves of the subject at each of at least two measured frequencies, and thereafter calculating a characteristic actual multiscalar response of the individual to the content of the presentation for analyzing the response of the subject during or after a given presentation.

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In the presently preferred form of apparatus, it is the amplitude of a brain wave signal at a particular frequency that is measured, and the so-called marginal values of these components are determined from changes in these amplitudes or intensities. However, the same or other apparatus may sample similar or different parameters or characteristics of brain waves at a particular frequency, such as power, phase angle, or the like. In any case, the desired parameter is selected so as to be indicative of the intensity or strength of the emotion at the target frequency. Accordingly, as used herein, the expression "amplitude" is to be taken in its general or non-limiting sense, i.e., as indicative of the intensity or strength of a signal of a given frequency at the time in question. The terms "intensity" or "strength" are therefore also sometimes used in the claims.

In the above illustrations, five frequencies were identified and the characteristic set of emotions associated with each such frequency was described. These emotions are sometimes referred to herein and in the claims as "base emotions" or "measurable base emotions" or words of like import, i.e., they are emotions that can be measured as to their presence, absence, and intensity, (including the presence of a polar opposite emotion) by the amplitude or intensity of a brain wave signal at that frequency. The measurable base emotions described included pleasure, arousal, dominance, and pictorial and abstract comprehension.

The more complex emotions able to be experienced by a subject are of concern in the instant method, and the more complex, overall emotional state of a subject that is sought to be determined is referred to herein and in the claims as a "composite emotional state." This state, at any one time, is represented by a coordinate point on a two-axis graph wherein one axis corresponds to one base emotion and the other axis to the other base emotion. Whereas more than two base emotions can be and are measured at one time, the comparisons of the two states or levels are always made two at a time. Points on any such two-axis graph are referred to as "coordinate points," and these points trace the composite emotional state of the subject from time to time.

Of course, the identity of any one graphically determined composite emotion depends on which base emotions are being compared graphically. Although subjects are capable of experiencing many more than the 100 separate emotions identified and referred to, for example, on the "Plutchik Placement" charts, for most purposes, knowledge of the quadrant wherein the coordinate point is located is sufficient to identify a composite emotion. The present invention identifies and/or measures composite emotional states of the subject by using values taken from base emotion measurements, namely those associated with a characteristic frequency. A series of composite emotional states therefore appears as a succession of points on the graph, each individual point lying generally within a certain quadrant on that graph and more particularly, lying a certain distance and direction from the origin.

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It will thus be seen the present invention provides new improved methods and apparatus for analyzing neurological response to emotion-inducing stimuli having a number of advantages and characteristics, including those pointed out herein and others which are inherent in the invention. Several preferred methods of practicing the invention having been described by way of illustration, it is anticipated that modifications to the described methods will occur to those skilled in the art and that such modification and changes may be made without departing from the spirit of the invention or the scope of the appended claims.

The manner in which the foregoing and other objects and advantages of the invention are achieved in practice will become more clearly apparent when reference is made to the following detailed description of the preferred embodiments of the invention set forth by way of example and shown in the accompanying drawings, charts and appendices wherein like reference numbers or legends indicate corresponding parts throughout.