Imagery-Eliciting Strategies: Review and Implications of Research

ABSTRACT - Recent research in cognitive psychology has focused on the use of illustration and imagery as facilitators of learning in a variety of situations. Results of this research are reviewed, with a key distinction being drawn between imagery-eliciting strategies and mental imagery. Speculations regarding the use of imagery in advertising are made in several important decision areas: advertising design and creativity, media selection and scheduling, measuring advertising effectiveness, and advertising regulation and public policy.

Citation:

Kathy A. Lutz and Richard J. Lutz (1978) ,"Imagery-Eliciting Strategies: Review and Implications of Research", in NA - Advances in Consumer Research Volume 05, eds. Kent Hunt, Ann Abor, MI : Association for Consumer Research, Pages: 611-620.

Advances in Consumer Research Volume 5, 1978      Pages 611-620

IMAGERY-ELICITING STRATEGIES: REVIEW AND IMPLICATIONS OF RESEARCH

Kathy A. Lutz, University of Southern California

Richard J. Lutz, University of California, Los Angeles

ABSTRACT -

Recent research in cognitive psychology has focused on the use of illustration and imagery as facilitators of learning in a variety of situations. Results of this research are reviewed, with a key distinction being drawn between imagery-eliciting strategies and mental imagery. Speculations regarding the use of imagery in advertising are made in several important decision areas: advertising design and creativity, media selection and scheduling, measuring advertising effectiveness, and advertising regulation and public policy.

INTRODUCTION

The field of advertising has a long tradition of borrowing explanations for advertising effects from psychology. Among the more prominent and fruitful constructs which have been used are those associated with various learning theories, ranging from classic contiguity principles to the more currently fashionable cognitive information processing approach. A major trend in recent research in cognitive psychology has been the study of imagery and its effects on human learning and memory. This rich research tradition has remained relatively obscure to consumer researchers, although it would appear to have major implications for the study of advertising effectiveness. The purpose of the present paper, therefore, is to provide a brief review of the research on imagery in psychology, followed by a discussion of possible implications for advertising decision-making.

REVIEW OF RESEARCH ON IMAGERY

Research on imagery has become increasingly popular recently, perhaps because the demonstrated effect of imagery is quite dramatic. Folklore suggests that a picture is worth a thousand words, yet it has been the task of empirical research to discover the full meaning and implications of this truism. In general, the literature on imagery indicates that presentations which elicit imagery are better remembered and more positively evaluated than presentations which do not. In this section, three strategies for eliciting imagery will be defined and their relationship to one another discussed. After reviewing research on each of the strategies, this section concludes with a summary and discussion of research findings.

Definition of Imagery

Imagery is defined as a mental event involving visualization of a concept or relationship. Despite its recent "re-discovery" by psychologists, mental imagery is still a rather poorly understood construct. One conception of mental imagery is physiologically based, wherein picture viewing and reported mental visualizations correspond to increased right hemisphere activity in the brain, while reading and verbal behavior correspond to a higher activation of the left hemisphere (Calloway & Harris, 1974; Galin and Ornstein, 1972; Morgan, McDonald, and MacDonald, 1971). These findings are based on studies with normal adults, but studies with brain-damaged or "split-brain" patients provide more dramatic evidence that the two sides of the brain differ. Nebes (1974) reviewed this research and concluded that the two sides of the brain are not necessarily specialized for storing different types of stimuli but rather process information in different ways. The left hemisphere processes information analytically and propositionally, while the right hemisphere involves holistic or parallel processing.

The implication of brain research is that mental imagery may be better understood in terms of parallel processing than picture processing per se. The parallel processing notion is compatible with the convincing arguments and evidence that memory is propositional with one common storage format (Anderson and Bower, 1973; Norman and Rumelhart, 1976; Palmer, 1975; Pylyshin, 1973). In other words, there may be no storage distinction between visual and verbal memory, but rather the information stored as propositions or schemata could be processed in different ways. Picture processing would not, however, result in a stored representation that is identical to that resulting from processing an equivalent verbal stimulus. The differences in storage representation are caused by differences in processing rather than by different and separate storage systems. This is a difficult concept and the reader is referred to Palmer (1975) for a discussion of how mental images may be represented in a common, propositional storage system. The point is that imagery processes can affect learning and memory even though images are stored in the same type of knowledge structure that accommodates verbal information.

These speculations about the nature of mental imagery do not explain how or why mental imagery aids memory. However, the definition of mental imagery offered here emphasizes that mental imagery is a way to process information. This working definition of mental imagery is useful in interpreting and applying research results, as well as for making speculations regarding theoretical explanations of imagery processes and effects. Unfortunately, an adequate theory of imagery and visual information processing does not yet exist, despite some recent progress (Paivio, 1971; Palmer, 1975; Yuille & Catchpole, 1977).

Imagery-Eliciting Strategies

Mental imagery is generally thought to be elicited by one of the following three types of strategies, or external treatment variables: 1) pictorial stimuli such as pictures, graphs, etc.; 2) concrete verbal stimuli; and 3) imagery instructions or direct inducements. Each of these strategies will be defined and described in turn.

Most researchers accept the common dictionary definition of a picture, using their intuition to identify pictorial material. Here, pictorial material (also referred to as a picture or an illustration) is defined as any two-dimensional representation in which the stimulus array contains at least one element that is not alphabetic, numeric, or arithmetic. According to this definition, an equation or arithmetic problem would not be a picture while a word containing a "picture-letter" would be considered pictorial. One well-known example of an illustration involving a "picture-letter" is the logo for Ford Motor Company in which a light bulb replaces the 'o' in "Ford." Illustrations should also be conceptually related in some way to the topic of the communication. The effectiveness of the picture may depend on how the picture relates to the verbal information; this will be treated later in the paper. However, pictures which are completely unrelated to the topic of the message will not be treated in this paper as they are assumed to be of no desirable consequence. For example, the use of sexy models in ads, when the model has no relationship to the product whatsoever, does not facilitate memory and may even promote negative attitudes toward the product and company (Marketing News, 1977; Steadman, 1969). On the other hand, seemingly unrelated pictures could conceivably set a mood that promotes desirable affective outcomes. For purposes of delineation, only pictures that are conceptually relevant to the message content will be treated in this paper.

The second type of imagery strategy--concrete verbal stimuli--is perhaps the most well-defined operationally. "Imagery values" for hundreds of words have been established by having readers rate the ease with which a word arouses sensory images. These ratings are available for nouns (Paivio, Yuille, and Madigan, 1968), for verbs (Lippman, 1974), and for words commonly used by children (van der Veur, 1975). Imagery ratings are independent of other word attributes such as word frequency and associative meaningfulness, so that this variable can be studied independently of their factors that affect recall.

The two types of strategies discussed so far are examples of external stimuli that presumably affect learning and memory indirectly by eliciting internal or mental imagery. Giving instructions to the recipient to form mental pictures is a more direct way to elicit this type of mental processing. Imagery instructions refer to a statement to the learner that directs him or her to form a mental picture of the concept to be learned.

The common thread running through all three strategies or experimental treatments is the assumption that they elicit, to some degree, mental imagery, which is in turn believed to enhance memory and learning. The research findings with respect to the effects of each of the strategies on learning are now summarized.

Research on pictures. Research in this area includes studies that test the effects of

1) supplanting (i.e., replacing) verbal information with pictures or

2) supplementing (i.e., repeating) verbal information with pictures.

The findings are grouped by type of material learned in the studies including single items, paired associates, and connected discourse (i.e., sentences or stories).

Paivio (1971) reviewed studies that compared memory for pictures to memory for words. The findings indicated that pictures are remembered better than either concrete words or abstract words. Memory for visual information greatly surpasses word memory according to several more recent studies (Frdelyi and Becker, 1974; Haber, 1970; Nelson and Brooks, 1973; Paivio and Csapo, 1973). The superiority of memory for pictures has been demonstrated using advertising stimuli in an earlier study (Shepard, 1967), which showed that pictures used in magazine advertisements are easily recognized again. Comparing memory for pictures to word memory, as many of these studies did, may be inappropriate, however. The verbal equivalent of a picture is probably not a single word but rather a story or description. Since memory for words in context is better than for an unconnected word list, picture memory may not surpass verbal memory if the two types of information are equated for meaning. Another factor that may contribute to the superiority of visual memory is schematic similarity among the pictures to be remembered (Nelson, Reed and Walling, 1976). In that study, pictures that were graphically similar, were not better remembered than words. This finding suggests that other variables should be controlled when testing the pictorial superiority effect.

Paivio (1971) also discussed studies that tested the effect of presenting a picture along with its verbal counterpart on word learning. Words were recalled better when the subject saw its accompanying picture; again, similar results have been obtained using advertising stimuli. Students recalled more company names when they had seen a pictorial depiction of the name (Lutz and Lutz, 1977). In that study, actual company names and pictures were taken from the Yellow Pages of a phone directory. Not all companies have the kind of names that lend themselves to pictorial depiction, so stimuli used in the study varied in terms of the degree of correspondence between the company name and its graphic depiction. Some pictures in the study were direct translations of the name, such as the picture for O'Bear Abrasive Saw Company which showed a bear holding a large letter "o". Other verbal-visual correspondences were not as direct. A cactus cowboy depicted Western Glass Company and Weiss Auctioneers used an owl to symbolize their name. It could be that pictures which are equivalent to their verbal counterparts facilitate memory for the company name better than pictures with a lower degree of correspondence. Perhaps future research on how verbal and visual information may be equated on the dimensions of meaning and amount of information will aid research efforts on this issue.

There are many studies on paired associated learning which indicate that a supplementary picture helps the viewer associate the two words to be learned. Learners shown a picture relating two items in a paired-associate learning task typically have significantly higher retention scores than those not presented with a picture and told only to learn the association through repetition (Davidson, 1964; Kerst and Levin, 1973; Lippman and Shanahan, 1973; Reese, 1965). One necessary condition for the facilitative effect is the interactive nature of the picture. An interactive picture integrates the two items in some mutual or reciprocal action. When the picture is not interactive and the items are depicted or imagined side by side, paired associate learning is not necessarily facilitated (Bernbach and Stalonas, 1973; Bower, 1972; Neisser and Kerr, 1973).

Interactive pictures facilitate memory for ads according to a study mentioned earlier, which used company-product pairs and their accompanying pictures from ads in the Yellow Pages of a telephone directory (Lutz and Lutz, 1977). The group receiving the interactive imagery treatment remembered significantly more company names than the non-interactive imagery group. Also, while the interactive imagery group remembered more brand names than its control group who saw only the company-product names with no accompanying pictures, the non-interactive imagery group did not differ significantly from its control group.

The interactive imagery group in the Lutz and Lutz (1977) study received two types of pictures, including picture-interaction items and letter accentuation pictures. In the latter type, some letter or letters in the brand name are made to look like the product or one of its characteristics. The logo for Mullin Lumber Company, in which the letters of "Mullin" are drawn as wood grain boards, is an example of letter accentuation. Picture-inter-action items unite a depiction of the brand and of the product or service in one picture. An example is the logo for Jack's Camera Shop which shows a playing card jack holding a movie camera to his eye. Students remembered picture interaction items better than letter accentuation pictures, which was also the finding in an earlier study (Lippman and Shanahan, 1973).

One dimension of an interactive picture that has not yet been investigated is the "dynamism" or animation of the interaction. Interactive pictures may be either dynamic or static, with dynamic interactions probably being the more memorable type. Television ads provide examples of dynamic interactive pictures in which the interaction is animated. Research on attention and reinforcement indicates that a visual stimulus change in the environment elicits attention to that action by the viewer (Kish, 1966). So the viewer's attention can be drawn to the important information by animating the interaction.

Presenting pictures along with stories and other forms of connected discourse is also facilitative. As mentioned before, pictures can accompany verbal material by supplanting or replacing part of it and by supplementing the verbal information. Although findings are not conclusive, some studies indicate that learning and attitude are positively enhanced when pictures replace some of the verbal information (Booher, 1975; Rigney and Lutz, 1976). When pictures completely replace the verbal text, however, comprehension may not be facilitated. Children who received a story in the form of a series of pictures remembered no more than students who read the printed text (Levin, 1973). Levin speculated that the pictorial treatment would have been more beneficial with some accompanying verbal labels. Another explanation of Levin's result is that his verbal comprehension test may have failed to test the kind of knowledge acquired by the pictorial treatment.

Most investigations in the literature on illustration have tested the effect of supplementing verbal material with pictures and have assessed outcomes with verbal posttests. In an earlier review, Samuels (1970) concluded that "pictures, when used as adjuncts to the printed text, do not facilitate comprehension." However, several recent studies indicate that supplemental pictures facilitate learning under some circumstances at a variety of age levels. Recent findings indicate that children learn more from a prose passage when it is accompanied by pictures (Bender and Levin, 1976; Lesgold, Levin, Shimron and Guttman, i975; Rohwer and Harris, 1975; Rohwer and Matz, 1975). Illustrations also aid children's memory for more difficult material that contains new concepts (De Rose, 1976). Seeing pictures apparently helps adults and high school students learn new concepts (Dwyer, 1972; Holliday, 1975). In Dwyer's study, pictures aided performance on graphic or drawing tests but not on verbal learning measures, indicating that pictures may result in non-verbal outcomes.

One recent study, however, found no facilitative effect for supplementary illustrations with adult populations. College students who read a passage about revolutions did not benefit from supplemental drawings, but mental imagery instructions did facilitate their performance (Rasco, Tennyson, and Boutwell, 1975). A second study yielded a similar outcome with high school seniors. Perhaps, when the visual information and verbal information are redundant and the verbal information is easily understood, illustration may not be beneficial for adult learners.

Research on pictures also indicates that learning is improved when students are asked to draw their own illustrations. Subject-generated pictures facilitated paired-associate and word learning (Bull and Wittrock, 1973; Wittrock and Goldberg, 1975), story comprehension (Lesgold, Levin, Shimron, and Guttman, 1975, Snowman and Cunningham, 1975), and recall of new concepts (Dansereau et al., 1975; Rasco, Tennyson, and Boutwell, 1975).

Although many ads are presented in a story format with accompanying pictures, no studies have empirically tested the differential effects of supplementing or supplanting the story line with pictures.

Research on concrete verbal stimuli. Research findings on the imagery value of verbal stimuli generally indicate that concreteness facilitates memory for words, paired-associates, and connected discourse. Studies will again be grouped around these three stimulus categories.

Paivio (1969) reviewed the effects of concreteness or imagery value on word recall. He cited a series of experiments that varied imagery value and word meaningfulness independently (or partialled our meaningfulness, and found that word recall was positively related to the level of word concreteness. More recent studies have confirmed the finding that words high in imagery value are remembered better than words of low imagery value when other factors affecting recall such as meaningfulness and frequency are held constant (Craig, 1973; Elliott, 1973; Griffith and Johnson, 1973; Paivio and Csapo, 1973; Wortman and Sparling, 1974).

No published studies have yet investigated the effects of word concreteness on recall of brand or company names. According to the research evidence, names that are concrete and picturable should be more memorable than abstract words, proper names, or abbreviated names.

Concreteness also affects paired-associate learning. When words are to be associated, memory for the pair can be affected by concrete connective words. Several studies varied the kind of connective words used to relate word pairs and found that verbs were more effective in facilitating memory for the pair than conjunctions or prepositions (Reese, 1965; Rohwer, Lynch, Levin and Suzuki, 1967). Although imagery values for the connecting words were not compared, it seems quite likely that the verbs had much higher imagery values than the conjunctions and prepositions used in those experiments. Other results suggest that embedding the word pair in the context of a sentence aids memory for the pair (Davidson, 1964; Levin, Davidson, Wolff and Citron, 1973; Lippman and Shanahan, 1973; Milgram, 1967). The sentences related the word pairs with action verbs, which probably made the association of the pair more concrete and picturable.

The use of concrete connectives in advertising messages has not yet been investigated. The research evidence suggests that messages which use concrete words to connect company name and product claims should make the messages more memorable. Assuming that action verbs are more concrete than linking verbs (although this has yet to be established empirically), the more effective ad will tell what the product does (its usage benefits) rather than what the product is (its attributes).

Connected discourse such as sentences prose passages, and stories, is better remembered if it contains concrete words rather than words of low imagery value (Anderson, 1974; Johnson, Bransford, Wyberg, and Cleary, 1972; Montague & Carter, 1973; Yuille and Paivio, 1969). However, words used in advertising stories and vignettes have not been systematically varied to test the thesis that concrete words would make the brand name and product claims more memorable.

Research on imagery instructions. The results of numerous studies on mental imagery instructions are reviewed and discussed by Paivio (1971) and will be only briefly summarized here. Giving learners imagery instructions facilitates paired-associate and word learning and the effects are much like those reported in the previous section on pictures. The interactive feature of the resultant image remains a necessary condition for maximum effectiveness. Learners told to mentally imagine two objects in interaction remember more word pairs than learners told to mentally picture the objects side by side or on opposite sides of a room.

One advantage of interactive imagery, as opposed to experimenter-supplied interaction pictures, is that the interaction can be idiosyncratic and bizarre, which has been recommended by ancient as well as modern day mnemonists (Lorayne & Lucas, 1974). The claim that bizarre images facilitate memory was not supported, however, by a recent empirical study (Nappe & Wollen, 1973). In fact, students in that study took longer to form bizarre mental images than "common" images. Although bizarreness does not appear to be facilitative, the related attribute of uniqueness or distinctiveness may be an effective attribute of facilitative mental images. A recent study varied the level of schematic and conceptual similarity of pictures and found that visual recall was no better than word recall under conditions of high schematic similarity (Nelson, et al., 1976). These results suggested that pictures or mental images which are too common may be confused with other visual information and may not be remembered.

Although there are no studies on the effects of imagery instructions on associating brand names with product claims in advertising, one particular ad provides an example of how to induce a common yet distinctive image. A Johnston's Yogurt ad directs the listen to "look for the sunny yellow cups" which probably elicits a mental image that is easy to form and yet is distinctive from other, similar products (unless other yogurt manufacturers use yellow containers as well).

Recent findings indicate that imagery instructions also facilitate memory for connected discourse. Children remember more after reading a passage when they receive imagery instructions, especially if the instructions are preceded by training in the use of this strategy (Kulhavy and Swenson, 1975; Lesgold, McCormick and Golinkoff, 1975; Pressley, 1976) Children may not benefit from imagery instructions, however, if the material to be learned is new or difficult (De Rose, 1976).

The pattern of effects is similar for adults. Imagery instructions facilitate memory for easy material such as sentences and narratives (Anderson, 1971; Anderson and Hiddi, 1971, Rasco et al., 1975). Imagery instructions per se appeared to have no effect on memory in one study, but closer analysis reveals that mental imagery did facilitate learning (Anderson and Kulhavy, 1972). Students in that study who reported that they learned the text passage by using "mental pictures" remembered more than students who reported not using mental imagery. The findings of this study are important because, while the nominal treatment of imagery instructions may fail to elicit mental imagery, reported use of mental imagery does correspond to increased recall. Another study showed no overall benefit from imagery instructions during a limited time period (Lesgold, Curtis, De Good, Golinkoff, McCormick and Shimron, 1974). However, adults who received the imagery instructions remembered more from the first half of the passage than did control subjects, suggesting that the imagery strategy required more time but was beneficial. The authors noted that imagery should not be considered a useful strategy if it produces no learning gains per unit time.

Directing adults to use mental imagery while learning new concepts may not facilitate learning, according to recent findings (Rigney & Lutz, 1976). The failure of mental imagery instructions to aid new concept learning in both adults and children is plausible because it would not be expected that people are capable of forming mental images of concepts with which they are not yet familiar.

One problem with trying to induce the learner to use mental imagery while reading is that the act of reading tends to interfere with imagery production, because both activities presumably involve some visual information processing. Findings by Levin and Divine-Hawkins (1974) indicated that imagery instructions were more facilitative when children listened to a passage rather than read it. Brooks (1967) also found that mental imagery was more readily elicited during listening than reading by adults. Most of the studies on imagery instructions told the subject to visualize while reading, so the results of those studies may have been even stronger if the subjects had listened to, rather than read, the verbal information.

Telling an advertising audience to form mental imagery while hearing or reading an advertising message has not been empirically tested, but the literature on this treatment suggests that it could facilitate memory for the ad. Imagery instructions may be especially effective with auditory media such as TV and radio, which would allow listeners to form idiosyncratic mental images while listening to the message.

Discussion and Summary

Outcome measures. The effects of imagery strategies must be viewed relative to the way learning outcomes are assessed. Tests of comprehension are most often only verbal, meaning that only verbal outcomes of presentation mode are assessed. Several studies tested the effects of pictorial treatments with graphic retention measures, which tapped knowledge not assessed by the verbal posttests (Dwyer, 1972; Lutz and Rigney, 1977).

Recent evidence on left and right hemispheric processes of the brain suggests that the left brain often dominates in processing and retrieving verbal or propositional information while the right hemisphere processes and retrieves information holistically. Levy, Trevarthen, and Sperry (1972) presented a dramatic demonstration of this difference when they showed split-brain patients a chimerical picture such as a face of which each half is actually from a different face. Using tachistoscopic methods, each half of the picture is sent to a different hemisphere and because of the nature of the patients' surgery, the hemispheres cannot communicate as in the normal brain. Results indicate that when the patient is asked to point to the face that he saw (i.e., recognize it), he points to the face corresponding to the half sent to the right hemisphere with no realization that the presented stimulus was composed of two different faces. When the patient is asked to verbally describe the features of the face that was shown (i.e., recall it), however, the face corresponding to the half projected to the left hemisphere is retrieved and described. This is convincing evidence that the left hemisphere is analytical and propositional while the right is holistic. But, more important to the point of assessing outcomes of treatments, this study demonstrates that the retrieval task may determine the nature of the information retrieved. Although this evidence comes from patients with altered brain function, normal individuals may display recall and recognition differences to some degree.

In assessing advertising effects, asking consumers to recall and state ad claims is probably a left hemisphere task. In contrast, a recognition test requiring the consumer is identify illustrations used in an ad may elicit more right hemisphere processing. The nature or type of information retrieved using these two approaches may differ. One recent study suggests that graphic assessment techniques reveal information stored in memory that is not necessarily retrieved by verbal measures (Rossiter, 1976).

Most of the outcomes assessed by the studies reviewed in this section dealt primarily with cognitive rather than affective outcomes of imagery-eliciting strategies. A few of the studies assessed the effects of imagery on attitude and found that imagery-eliciting strategies seem to promote positive attitudes in addition to facilitating learning. Samuels (1970) concluded in his earlier review on imagery effects that although pictures may not always affect cognitive outcomes, they do seem to facilitate favorable affective outcomes. More research is needed to clearly establish the effects of imagery on attitude.

Imagery-eliciting strategies may also affect decision making processes. Some evidence suggests that people weight concrete examples more heavily than abstract information when making judgments or decisions (Nisbett, et al., 1976). Thus outcomes other than learning alone should be considered when determining the effects of imagery-eliciting strategies.

Summary of facilitative conditions. Although findings are mixed, the literature on imagery generally indicates that pictures, concrete words, and mental imagery instructions facilitate memory and may enhance attitude as well. Individual differences in prior knowledge may influence the size of the imagery effect. Pictures may not help a reader who already knows a lot about a topic. For example, adults in the Rasco et al. study (1975) did not benefit from seeing pictures. These readers did benefit, however, by forming their own mental images while reading. The opposite pattern of results was found in a study with children who were learning material intended to be difficult or instructional. The children remembered more when adjunct pictures accompanied the text than when they were given mental imagery instructions (De Rose, 1976).

These seemingly conflicting results may be explained by an interaction hypothesis that mental imagery is facilitative under conditions of prior familiarity while pictures are more beneficial when the learner has less prior knowledge. There are several plausible arguments favoring this hypothesis. People should not be capable of forming mental images of concepts that they have not yet acquired, so a mental imagery strategy would be rather ineffective for new concept learning. Pictures, on the other hand, do aid learning of difficult material but may not make any difference when an adult reads prose text that is easy to comprehend.

Another way to look at the differential effectiveness of these strategies is that learners may benefit more from their own strategies than imposed strategies, under certain conditions. Bobrow and Bower (1969) demonstrated that subject-generated verbal mediators were superior to experimenter-provided verbal mediators in a paired-associate learning task. Since that study, other researchers have turned attention to the potential value of instructing or training learners to apply their own learning strategies. Picture drawing and mental imagery generation are examples of learner-generated strategies that appear to facilitate learning when the learner is capable of performing these tasks.

Other variables that may affect the strength of the imagery effect include characteristics of the picture such as figural interaction and dynamism and the relationship between the verbal and visual information in a message. Pictures must be related to but not always repetitive of passage content to be facilitative. Adults who are good readers may not benefit from viewing a supplementary picture when they read simple narratives or familiar material. When the illustration presents additional information, however, picture viewing results in more effective and efficient learning. Children or learners with little prior knowledge seem to benefit from illustrations whether they supplement or supplant some of the verbal information. Hence, the learner's prior knowledge may interact with the relationship of verbal and visual information.

IMPLICATIONS FOR ADVERTISING

A consideration of the principles and effects of imagery is relevant to a number of important decision variables in the advertising mix. While little empirical research on imagery and advertising has been undertaken to date, the perspective provided by the imagery literature can, nevertheless, be useful in structuring advertising decision-making along lines consistent with imagery principles.

The following discussion of advertising implications is not intended to be exhaustive and conclusive, but rather speculative and limited to the areas showing the most obvious potential benefits of adopting an imagery perspective. The areas to be considered include the use of imagery in 1) advertising design and creativity, 2) media selection and scheduling, 3) measuring advertising effectiveness, and 4) advertising regulation and public policy.

Advertising Design and Creativity

Imagery has its most obvious implications in the area of advertising design. For instance, the use of pictures in ads is hardly a new idea to advertisers, who have relied on illustrations for years in the quest for more interesting and persuasive advertising campaigns. However, the principles of imagery suggest a richer perspective on the problem of using pictures to communicate.

Some illustrations are more effective than others. For instance, the use of interactive imagery, wherein a brand name is pictorially portrayed in relation to a product concept, should result in increased association of the brand and its attributes or benefits as demonstrated by Lutz and Lutz (1977). In contrast, a non-interactive image portraying either the brand or its benefits (or perhaps both, but not in a single, integrative picture) may result in retention of the pictorially presented stimulus, but not the critical relationship between the brand and its benefits. Krugman (1978) has argued for the use of "memorable" illustrations as an aid to effective advertising. The concept of interactive imagery suggests that it is not enough that the illustration be memorable but that it must also depict the relationship between the brand and its proffered benefits. A Los Angeles exterminator named Arrow Pest Control uses as its logo an insect pierced by an arrow. Remembering the illustration also means remembering the brand name (Arrow) and its product offering (bug killing). A cursory examination of much contemporary advertising suggests that many advertisers conjure up dramatic illustrations which do little to communicate the brand-benefit linkage.

From an imagery perspective, then, appropriate illustrations can vividly portray information - i.e., the concepts that the advertiser wishes to communicate. When pictures do not communicate relevant information, they should not be expected to enhance advertising effectiveness, except perhaps indirectly, as under the distraction hypothesis (Bither, 1972; Wright, 1973). One important issue in treating illustrations as information presentations is whether they should serve as supplements to, or as substitutions, for, verbal presentations of the same information. While the former use would imply some redundancy in the commercial message, this redundancy may constitute a type of repetition within the ad, which is presumably a desirable feature. Additionally, the use of pictures in lieu of verbal copy claims may be hazardous, in that audience interpretations of pictures may be more varied than comprehension of verbal claims. A picture may indeed be worth 1000 words, but it may not be the same 1000 words for all members of the audience. The use of concurrent verbal stimuli may help to homogenize response to the illustration while preserving the increased vividness gained by use of the picture.

Thus far, the use of imagery in advertising design has focused on external imagery in the form of pictures and illustrations. Pictures are assumed to be facilitative because they elicit internal or mental imagery. Mental imagery may be induced through means other than the presentation of pictures, however. The use of concrete terms, verbal descriptions of pictures, and imagery instructions are other ways to elicit mental imagery in the mind of the potential consumer.

An interesting consideration in the use of nonpictorial spurs to mental imagery is the possibility that there are two operators at work in the process. One operator is the ability of the consumer to come up with an appropriate image without being shown one by the advertiser. It would seem likely that this ability is not equally present in all audience members and that some will be "lost" at this step. The second operator conceivably at work is the idiosyncratic nature of the images that are created. The power of the human imagination is vast and may supercede any advertiser-provided stimulus in being personally relevant or vivid to the consumer. Thus, for those consumers who do form mental images, the resultant images may be much more powerful than those stimulated by an illustration.

One may question whether consumers are sufficiently involved with commercial advertising to actually devote time and effort to forming a mental image. A similar criticism applies to the cognitive response model of communications effects (Wright, 1973) to which an ingenious, if risky, counterploy by an advertiser might be to instruct the consumer to "think about it" (i.e., generate cognitive responses) (Ray, 1977). A similar solution to the mental imagery problem may involve telling the consumer to "imagine yourself" in a particular situation or performing a certain behavior.

Media Selection and Scheduling

Viewing the communications task from an imagery perspective immediately suggests that certain media vehicles are more suited to certain kinds of imagery uses. The various media have different strengths and weaknesses which can be taken into consideration in planning a campaign relying on imagery principles. One basic distinction which has been made is that between the broadcast media (TV, radio) and print media (magazines, newspapers). The former are presumably more "intrusive" but characterized by less audience involvement than the latter (Krugman 1965), a source of concern to many advertisers. Consideration of imagery principles may help advertisers to overcome or perhaps even benefit from low involvement on the part of consumers.

Television. This medium is especially suited to the use of dynamic interactive imagery, thus making full use of the power of illustrations in affecting learning, attitudes, and behavior. The use of action in the commercial can focus the viewer's attention on the critical interaction between the brand and the product or service and make it much more memorable. An example of this type of imagery is the ad for Hunt's tomato sauce in which thick tomato sauce is shown being poured into the "u" in Hunt's. This is an example of a letter accentuation image, which is useful for brand names that cannot be depicted pictorially. An example of dynamic imagery that may not direct attention to the brand-benefit association is the ad for AMC that shows a number of interesting pictures appearing next to a moving, flashing line. The line holds the viewer's attention very well, but the viewer may fail to notice what brand was advertised. Thus, the ad may not direct the viewer's attention to the critical information.

Another imagery technique made possible by the capability of TV is modeling. Viewers can be shown the actual use of a product, thus portraying the behavior desired of the audience, as well as communicating beliefs and cognitions about the product.

As noted previously, viewers are often described as having "low involvement" when viewing TV ads. Viewing pictures as opposed to words seems to require much less involvement or cognitive processing for perception and comprehension. As suggested by Krugman (1978), right hemispheric processing may be at work. This can work to the advertiser's advantage, since it takes less effort to attend to and comprehend a picture than is required to understand an equivalent amount of information presented verbally. Thus the use of pictures and models to create interactive, highly memorable images is especially important in TV advertising since this is generally considered to be a low involvement medium.

Radio. While the use of imagery in radio advertising has certain limitations inherent to the medium (i.e., low involvement and inability to present information pictorial ), creative inducements to use mental imagery could make radio ads as effective if not more effective than media which present external imagery. The literature on mental imagery indicates that subject-generated imagery may be superior to picture viewing for adult learners. Lorayne and Lucas (1974) in their popular The Memory Book, claim that bizarre, unique, individualized mental images are the most effective. Instructions to use individual mental imagery may result in not only improved memory for the message, but also increased involvement by the listener.

There are several ways to induce imagery on radio. One is to use concrete language to describe a picture, hopefully inducing the listener to form a mental image. The description should ideally be of an interactive image. Perhaps the most effective approach would be to coordinate radio descriptions with dynamic interactive pictures that are presented in TV ads. A description of the image may elicit memory for the already viewed dynamic image so that the listener "sees" the picture again in the "mind's eye".

Another way to elicit imagery is to give imagery instructions to the listener either directly or implicitly, telling the listens to picture themselves in a situation. An example of imagery instructions in a radio commercial is the Delta Airlines ad that directs listeners to "raise your hand, look at your watch, and repeat after me: Delta is ready when you are." The listeners mentally picture themselves looking at their watches and thinking about Delta Airlines' attribute of being on time.

Print. Magazines and newspapers are assumed to enjoy higher involvement on the part of their readers so ads in these media can safely devote more of the communications task to verbal information. The relationship between the verbal and visual information presented in print media may be different than in media with lower audience involvement. Pictures can supplement the main points made verbally.

Also a particular advantage in the print media as a result of higher reader involvement is the possibility of providing mental imagery instructions with somewhat more assurance that some portion of the audience will actually attempt to form mental images. Another related possibility would he to leave space in the ad for readers to draw a picture of themselves using the product. A modified picture-generation task such as "connect the dots" may be successful. Even the covert response of thinking about drawing the picture may help to crystallize an image in the consumer's mind.

Outdoor. Outdoor advertising or billboards are mentioned here only briefly as a medium which can benefit greatly from the use of imagery principles. Severely restricted in space and exposure time, a billboard will be most effective by arousing some sort of mental imagery in the consumer, either through the use of illustrations or brief imagery instructions. It is also noted in passing that certain types of mechanical billboards may take advantage of dynamic interactive imagery, although this would be the exception rather than the rule.

Media mix. In selecting the media mix for a complete advertising campaign, integrated use of imagery-eliciting strategies in the various media should be one of the objectives. For instance, the more involving print media might use concrete language and imagery instructions, with the broadcast media serving the role of eliciting a reconstruction of those images. As another example, television advertising might utilize dynamic interactive pictures, with static portrayals of the same picture appearing in print form. The basic notion is to use each media vehicle to its own particular advantage, perhaps shifting the mix to match the type of imagery appeal being used. A campaign emphasizing dynamic interactive imagery may use more TV initially, followed by a shift into more print media and radio spots.

Media scheduling. One of the primary advantages offered by the use of imagery-eliciting strategies in advertising is the improved efficiency of communication. Presumably the same advertising effects can be achieved with fewer exposures to imagery-eliciting ads than their non-image counterparts. Germane to this point, Tversky and Kahneman (1973) discuss the so-called availability hypothesis: "any incident that makes the occurrence of an event easy to imagine or recall is likely to enhance its perceived frequency". This hypothesis has obvious implications for the problem of ad wearout. If an image-eliciting ad is easier to recall, consumers are likely to believe that they have seen the ad more often. Thus, the ad may have a shorter "life cycle" before becoming an annoyance to consumers, unless the ad is scheduled less frequently to counteract this effect. Less frequent scheduling of the ad means improved cost effectiveness.

Measuring Advertising Effectiveness

Hierarchy-of-effects. Perhaps one of the most controversial issues in advertising evaluation revolves around the notion of the "hierarchy-of-effects" (e.g., Lavidge and Steiner, 1961). Critics have assailed the hierarchy as inaccurate in its portrayal of response to low involvement advertising (e.g., Krugman, 1965), and others have suggested that as many as three different forms of hierarchy may exist (Ray, 1977). Imagery may be an important determinant of the power of a hierarchy-of-effects approach to modeling communications effects.

In its simplest form, the hierarchy consists of three steps: 1) cognition, or beliefs about the brand, 2) affect, which represents attitude toward, or evaluation of, the brand, and 3) conation, representing behavior with respect to the brand. For "high involvement" products, the steps are believed to occur in the order listed above, while in the "low involvement" case, Steps 2 and 3 are thought to be reversed (Ray, 1977). If this reversal is in effect, then traditional forms of advertising pretesting which rely on brand attitude as a surrogate for subsequent market behavior may be quite useless. Consumers are viewed as being in a very passive role, learning "without involvement" (Krugman, 1965) and not forming any true evaluation of the brand until after initial purchase.

The use of effective imagery strategies in advertising may act to 1) lift the low involvement situation to a higher level of involvement, 2) promote non-verbal cognitions and 3) elicit attitudes toward that brand, thus making the cognition-affect-conation hierarchy a viable one for assessing advertising effects. Pictorial treatments are associated with more positive attitude toward the message, according to several studies reviewed earlier. Nisbett, et al. (1976) cite several studies showing that concrete information is much more influential in human judgmental processes than is more abstract information. It is not unreasonable to expect that the very presentation of concrete information in an ad may stimulate the sorts of judgmental processes upon which the hierarchy-of-effects model rests.

Recall vs. recognition. A related issue in advertising evaluation is the appropriate measure of consumer learning outcomes. Krugman (1965, 1978) has argued for the use of recognition rather than the more traditional verbal recall. The importance of using visual in addition to verbal assessment techniques after picture viewing has been recognized recently in consumer research. Rossiter (1976) reasoned that product information perceived and retrieved visually may differ considerably from attribute information retrieved verbally. Children at several age levels in his study appeared to have much information about cereals available when drawing a picture of the product that did not coincide with verbal recall. More importantly, this visual information also influenced their preferences to some extent.

The use of imagery in advertising may engage the brain more fully in the response to the ad. Both the left and right hemispheres probably become more activated in processing a combination of verbal and pictorial information. Ad testing technology must keep pace by using procedures adequate for assessing the effects of the image-related portion of the ad.

Advertising Regulation and Public Policy

Recent consumer-oriented public policy has heavily emphasized the need for advertising to serve an informational function for the consumer. The essential thrusts of affirmative disclosure, nutrient labeling, and advertising substantiation all rest on the notion of the consumer as an information processor. Unfortunately, most of the focus has tended to be on verbally presented information, rather than on visually presented information, despite the fact that the FTC is concerned about "implied" product claims.

As noted by Eighmy (1978), much of the work being done presently in public policy relies on the use of copy testing, which has as its main focus verbal copy claims, and to a lesser extent the implications of a visual context. Yet good imagery in advertising may be much more powerful than any verbal claim, in part due to the former's concreteness (Nisbett, et al., 1976). Thus, public policy directed at advertising should immediately shift greater attention to the imagery in advertising in order to more adequately perform its job of protecting/informing consumers. The prevailing view of the consumer as an information processor must be broadened to encompass not only left hemispheric verbal processing, but also the more subtle yet perhaps more powerful right hemispheric processing of visual imagery.

CONCLUSION

This paper has attempted to summarize briefly the research on illustration and imagery which has appeared primarily in the psychology literature. Implications of these findings for research on, and the practice of, advertising would seem to be rather far-ranging. A number of potential issues have been raised for the application of imagery principles to advertising decisions. Further research is needed to determine which areas of advertising can benefit most from an imagery perspective, and how communications in general can be improved through the use of imagery.

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