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Enhancing the Efficacy of Split Thirty-Second Television Commercials: An Encoding VariabilityApplication Author(s): Surendra N. Singh, Denise Linville and Ajay Sukhdial Source: Journal of Advertising, Vol. 24, No. 3 (Autumn, 1995), pp. 13-23Published by: Taylor & Francis, Ltd.Stable URL: http://www.jstor.org/stable/4188978Accessed: 24-04-2015 19:07 UTC

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Enhancing the Efficacy of Split Thirty-Second Television Commercials: An Encoding Variability Application Surendra N. Singh, Denise Linville and Ajay Sukhdial

The split 30-second commercial format has become a regular feature of today's television advertising. Yet, little is known about the effectiveness of commercials presented in the two halves of a split :30. The authors report findings from a laboratory experiment in which the similarity of commercials presented in the two halves of a split :30 format was systematically varied. In a factorial design, subjects were exposed to either two identical :15s, two very similar :15s, or two very different :15s for the same brand. Memory of the adver- tised brand was measured after either a short interval (within a few minutes of message exposure) or a long interval (the next day). Results provide preliminary support for the assertion that presenting identical :15s leads to better memory after short intervals and presenting different :15s produces better memory after long intervals. The findings are explained through a variation of the encoding variability theory.

Surendra N. Singh (Ph.D. Univer- sity of Wisconsin, Madison) is the Noble Foundation Chair in Market- ing Strategy at the Oklahoma State University, College of Business, Stillwater, Oklahoma.

Denise Linville (Ph.D. University of Kansas) is an assistant professor in advertising in the School of Journal- ism at the University of Kansas.

Ajay Sukhdial (Ph.D. University of Oregon) is an assistant professor of marketing, School of Business, Oklahoma State University. The study was supported by research grants to the first author from the American Academy of Advertising, the University of Kansas General Research Fund, and the School of Business Research Fund. Part of the work on this manuscript was done while the first author was on sabbatical leave.

Journal of Advertising, Volume XXIV, Number 3 Fall 1995

Most television commercials today are in a 30-second format, but shorter commercials (less than 30 seconds) have become increasingly popular. In 1992, 32% of all television commercials were 15 seconds long (Arbitron Annual Report 1992). One format that advertisers commonly use for short messages is the split :30 unit. The split :30 format-advertising two sepa- rate brands within a single 30-second unit-has been permitted by U.S. television networks since June 1983. Initially, networks insisted that the sponsor of a split :30 ad be identified at the beginning of the spot and that a two-second bridge statement (e.g., "And here is another product from [spon- sor]....") be used between the two halves of a split :30 (Marketing News, February 1984, p. 6). However, most such restrictions have been dropped, and advertisers are free to do what they please with their split :30 buys.

We conducted a study to investigate the effect of using ads for a single brand in both halves of a split :30 commercial. Advertising repetition is a common strategy. It is used to improve brand memory (Craig, Sternthal, and Leavitt 1976; Singh, Rothschild, and Churchill 1988), enhance attitudi- nal response (Rethans, Swasy, and Marks 1986), and induce purchase be- havior by attempting to bring the target brand into buyers' consideration sets (Hauser and Wernerfelt 1990). Often, commercials for a single brand are repeated within one program (Unnava and Burnkrant 1991) and one commercial pod (Murry, Lastovicka, and Singh 1992).

In showing two ads for the same brand in a split :30 format, an advertiser has many choices. We examined the following three alternatives:

1) Present one 15-second message twice. 2) Present one 15-second commercial and then a very similar version of

the same message. 3) Present one 15-second commercial and then a very different version

of the same message.

Specifically, we attempted to ascertain which of the ad-version combina- tions in a split :30 format is best to enhance memory of the advertised brand. The study is important for theoretical as well as practical reasons. Theoretically, our findings should enhance understanding of the value of

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14 Journal of Adverti8ing~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

message repetition in a split :30 format. Although advertising repetitions are ubiquitous, the value of

repeated ads is unclear (Pechmann and Stewart 1988). On the basis of encoding variability theory, we tested the prediction that there will be a significant interac- tion between the ad-version combination used in a

split :30 format (e.g., presenting identical, similar, or different versions of a message) and the time lapse between the ad exposure and memory measurement. We proposed that when memory is measured after a short delay, presenting two very different versions of a message in a split :30 format will lead to lower recall of the message arguments than presenting two identical versions. In contrast, when memory is mea- sured after a longer delay, presenting different ver- sions should lead to higher recall than presenting identical versions. Using similar versions of the mes-

sage should produce an intermediate effect. In a practical vein, our study addresses advertisers'

concern that a pairing of two :15s for two very differ- ent brands may be perceived as two quick cuts evok-

ing negative viewer reactions (Marketing News, Feb-

ruary 1984, p. 6). By using the two halves of a split :30 to promote the same brand rather than two differ- ent brands, an advertiser might avoid the problem of two ads coming across as two quick cuts. Finally, Gay (1985) mentions that pairing one brand with another in a split :30 can be a problem for multibrand compa- nies (e.g., pairing two competing brands of cereal from the same company may be inappropriate). Advertis-

ing the same brand in both halves of a split :30 could be an alternative.

Encoding Specificity, Encoding Variability, and Message Recall

The fact that repeating an item improves memory of it is widely accepted and empirically verified. How- ever, the strength of the repetition effect can be a function of many variables, including the context in which the message is presented and the context in which the encoded message is retrieved (recalled).

The role of context in recalling information is clearly emphasized in the encoding specificity principle (Thomson and Tulving 1970), which states that "what is stored is determined by what is perceived and how it is encoded, and what is stored determines what retrieval cues are effective in providing access to what is stored" (Tulving and Thomson 1973, p. 353). In other words, recall is facilitated if at the time of re- trieval (remembering) the same contextual variables are present as were present at the time of initial

encoding or storage (i.e., when the information was

presented to the subject). At the time of storage, in- formation to be remembered is encoded along with contextual information. Therefore, at the time of re- membering, cues (hints) about the storage context should make retrieval (remembering) easier. This is

why aided recall scores are higher than unaided re- call scores, and recognition test scores are usually higher than either aided or unaided recall scores. As

Klatzky (1980, p. 230) has noted: Recall is the result of a rather complex interaction between encoding (or storage) processes and re- trieval. In order to best get at information stored in memory, the retrieval operation should have available the same information that was present at the time of encoding. That means that the en- coding of the input should match the cues for re- trieval.

Given the importance of context in encoding and retrieval of information, we must specify exactly what is meant by context. According to Crowder (1976, p. 297), "context itself includes a variety of interocep- tive and exteroceptive background events occurring during presentation of nominal stimuli. Not only gas- tric cues and occasional sensory messages, but also streams of cognitive episodes and strategic decision

making are included." Similarly, Glenberg (1976, p. 5) views context as multidimensional and encompass- ing such aspects of the experimental situation as "the other stimuli, the experimental task, the experimen- tal room, the subject's strategies, and the subject's internal physiological and psychological states." Other verbal learning theorists (e.g., Flexser and Tulving 1978; Kintsch 1974) also subscribe to the notion of context as including not only the other information

presented with the target information, but also the

subject's mental and physical states and the

extraexperimental surroundings (Klatzky 1980). Bower (1972) suggests two ways in which a context

can change: systematic contextual changes and random contextual drift. Systematic contextual

changes are usually abrupt and are deliberately in- troduced by the researcher. For example, in a second

presentation of some target (to-be-remembered) in- formation, the experimenter may change the room in which the information is presented or provide differ- ent background information (along with the target information). Random contextual drift is more subtle and is time based. As Bower (1972, pp. 93-94) ex-

plains: .... there is a slow drift or gradual change in the prevailing context as other items or events occur

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Fall 1995 15

during a lapse of time. The change in context pre- sumably grows progressively over elapsed time. Thus, the change in context is rarely total; states of the mind recur many times over .... Nonethe- less, the average overlap between the contexts at times t and t+k will decrease to some asymptotic proportions as k increases.

Given the preceding definition of context and in light of the encoding specificity hypothesis, if a mes- sage is presented twice within the same context, mea- suring message recall shortly after the second pre- sentation should result in a higher score than mea- suring recall after a substantial delay. The reason for this expectation is that in addition to the contexts being the same at the two encodings, substantial over- lap is likely between the contexts at the two encodings and the context of the recall test.

In real-life situations, information usually is pre- sented in one context and is recalled in another con- text; that is, memory is accessed after a delay. Most studies have shown that repeating an item in differ- ent contexts helps delayed recall (Glenberg 1976; Madigan 1969; Melton 1967). Presenting an item in multiple contexts is argued to increase the number of routes to memory of the repeated item, which in- creases the probability of overlap between the infor- mation in a retrieval cue and that encoded in memory (Melton 1970; Unnava and Burnkrant 1991).

According to Cuddy and Jacoby (1982), the most sophisticated and popular explanation of this phe- nomenon is offered by Glenberg (1979) via encoding variability theory (EVT). The underlying logic of EVT is the same as that of the encoding specificity hypoth- esis. Both theories recognize that when an item (stimu- lus) is presented to a subject, the representation of the item in memory depends on the contextual vari- ables present at the time of encoding. In other words, the same physical stimulus (nominal stimulus) item may be represented or encoded differently (functional stimulus) if it is presented in a different context. Furthermore, both assume that recall depends on the correspondence between the two functional stimuli, (1) the functional stimulus at encoding, which is a function of the nominal (physical) stimulus plus the encoding context, and (2) the functional stimulus at the time of testing, which depends on the nominal retrieval cue and the testing context. The greater the correspondence between the two functional stimuli, the better the chance of recall. EVT differs from the encoding specificity hypothesis in the assumption that, because the subject may be unable at the time of retrieval to reinstate (recreate) the context present at encoding, as ordinarily would be the case in delayed

memory measurement, presenting an item in mul- tiple contexts helps retrieval. As Crowder (1976, p. 281) explains:

What becomes crucial is the context operating at the time of retrieval, in particular whether the subject can recreate some or all of the contextual cues available during presentation. Assuming that ordinarily he cannot recreate all the context that has prevailed at presentation, then an item stands a higher chance of retrieval if it has occurred in two contexts-two conceptual neighborhoods-than if it has occurred in only one. The usefulness of multiple encodings may come from having two re- trieval routes directed at the same memory trace.

The preceding discussion suggests a crossover in- teraction between the context in which a message is presented and the time of memory measurement. Spe- cifically, if memory is measured after a short inter- val, message recall should be higher when the item has been repeated in the same context than when it has been repeated in different contexts. However, if memory is measured after a long interval, recall should be higher when the item has been presented in multiple contexts than when it has been presented in the same context.

Crossover Interaction and the Split :30

If a television commercial is shown in the two halves of a split :30 commercial format, we should be able to obtain the crossover interaction observed in verbal learning studies by systematically altering the con- textual (executional) cues surrounding the focal mes- sage. Specifically, we predict that when memory is measured after a short delay, presenting two differ- ent versions of a 15-second spot in the two halves of a split :30 should lead to lower message recall than presenting two identical versions. In contrast, when memory is measured after a longer delay, presenting different versions should produce higher message re- call than presenting identical versions.

First, consider the use of two different versions of a 15-second commercial. In creating the two different versions, the advertiser could deliberately introduce systematic contextual changes such that each ver- sion has the same basic message arguments but dif- ferent executional elements. In this case, one would reasonably expect the encoding contexts surrounding the basic message arguments in the two versions to be different. The strength of the difference in the encoding contexts of the two versions would be di- rectly proportional to the differences in the executional cues.

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16 Journal of Adverti8irtg

Now consider using the same 15-second spot in both

parts of a split :30. There is little, if any, systematic context change between the two presentations aside from the typical two- second bridge statement. Any contextual changes between the two presentations are likely to be due to random contextual drift such as random physical changes in the environment (e.g., a noise may be present in the room during the second half of the split :30 that was not present during the first half and vice versa) and minor random fluctua- tions in the viewer's physiological and psychological states (i.e., what the viewer was thinking or feeling during the first half may be somewhat different from what he or she is thinking or feeling during the sec- ond half). At the very least, the viewer might think

during the second half, "Didn't I just see this same commercial?" It appears reasonable to assume that some nonsystematic, random contextual drift occurs between the two presentations of identical :15s in a

split :30 format, even though the two encoding con- texts are very similar. This situation is akin to the EVTs scenario of a very modest change in context between two presentations.

If presenting identical messages in a split :30 in- duces only moderate contextual change whereas pre- senting two very different versions of the same mes-

sage leads to significantly greater contextual change, measuring recall of the message arguments after short and long intervals should reveal a crossover interac- tion similar to the one observed in the verbal learning literature. Specifically, we propose the following hy- pothesis predicting a significant interaction between the ad-version combination used in the two halves of a split :30 and the delay in memory measurement.

Hypothesis: Presenting the same 15-second commercial in the two halves of a split:30 will lead to significantly higher recall lev- els at a short measurement interval but lower recall at a longer interval. The re- verse will occur if the two halves of the

split:30 contained two different versions of a 15-second commercial.

In our study, the delayed measurement was taken after 24 hours. At best we should expect no memory loss in the different-versions condition and we should

expect a significantly greater memory loss in the iden- tical-versions condition, hence the predicted interac- tion. To put it simply, we predict that repeating a

message after executional elements are altered will result in less memory decay over time than repeating an unaltered message.

We do not propose an explicit hypothesis on the effects of presenting two very similar versions of a 15-

second commercial in the split :30 format, but we

expect the results to be between those of the identi- cal-versions condition and the different-versions con- dition. For exploratory purposes, we include this con- dition in our operationalizations.

Method

Design

To test the hypothesis, we used a two (retention intervals: short vs. long) by three (combinations of 15-second ad versions in the split :30 commercial: identical :15s vs. very similar :15s vs. very different :15s) fully factorial experimental design. Two groups of control subjects were used to test the effect of rep- etition, resulting in a total of eight cells. Control sub-

jects were exposed to the target commercial only once.

Subjects

A total of 140 undergraduates at a large midwestern

university participated in the study. Subjects signed up for various available time slots, and were assigned randomly to the treatment conditions.

Procedure

Subjects were invited to view two news shows in two half-hour sessions. They were not told the pur- pose of the study. They were informed that they were about to see a late night news show taken from a television station outside their own viewing area and that they would be asked for their opinions about the news show. Subjects viewed the news show in groups of 14 to 17. At the end of the show, all subjects filled out a brief news evaluation form. Subjects in the short retention interval condition then answered a

questionnaire on several dependent variables related to the commercials. Subjects in the long retention interval condition were asked to come back the next

day for a second viewing. When they arrived, they did not view the news show but filled out the same ques- tionnaire as the short retention interval group. All

subjects were debriefed after data collection.

Stimulus Material

Commercials. Because of the difficulty of finding three regional 15-second commercials for the same brand that met all of our criteria for the experiment, we created the experimental commercials by editing a pool of real commercials. Two of the commercials

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Fall 1995 17

were to be very similar (but not identical), and the third commercial was to be very different from the other two. To create the similar commercials, we se- lected two 30-second commercials for a supermarket chain that was not within the testing region. Both commercials promoted the produce department of the supermarket. They were similar in that they were both slice-of-life commercials with the same theme, music, and voice-over. They differed only slightly in the characters and settings depicted in the scenes. We edited one of these commercials to create a 15- second informational target commercial, eliminating all audio and replacing it with our own music and a female voice-over making rational claims about the produce of the advertised supermarket. We created an informational commercial so that subjects would have objective claims to remember. Next, we created a very similar version of the target commercial by editing the second commercial down to 15 seconds, removing all original audio and replacing it with the same audio as in the target :15.

To create a very different version of the target com- mercial, we prepared a 15-second commercial by edit- ing scenes from a regional commercial for another product and splicing in shots of the produce and logo. We overlayed very different music and used a male voice-over. This version was a montage ad in which the theme, music, and voice-over were very different from those in the other two ads. However, the copy for all three ads was identical and the commercials all contained the same product claims that could be recalled in memory tests. The message content in all three commercials was identical in all aspects to pre- vent confounds due to message claim or copy differ- ences.

We pretested the three advertisements for similar-

ity and difference by using a 7-point semantic differ- ential scale with anchors avery similar" and "very dissimilar." The subjects used in the pretest were different from those used in the main experiment, though they came from the same subject pool. The average similarity rating for the target ad and its similar and different versions was 2.26 and 5.87, re- spectively. Also, the similarity rating for the similar and different versions was 5.63. A t-test showed the different commercial to be significantly (p < .05) dif- ferent from the target commercial (t = 18.13) and its similar version (t=13.37).

We also selected five filler commercials from a pool of regional commercials. All of the them were for

products that were not sold in the area and each was for a different product category. None of them adver- tised a supermarket or produce.

Videotapes. Four videotapes were prepared with commercials embedded in portions of a late night news show taken from a station in the southeast United States. The news show was edited to run 13 minutes and commercials were embedded in two pods between news segments.

On all four tapes, the first pod of commercials con- tained three fillers (i.e., nonexperimental commer- cials); two were 30 seconds and one was 15-seconds. The second pod had both experimental and filler com- mercials. On the first three tapes, the second pod of commercials began with two 30-second commercials that were followed immediately by the target split :30 which consisted of identical 15-second halves in tape 1, the target commercial and its very similar version in tape 2, and the target commercial and its very different version in tape 3. The three tapes thus op- erationalized the three combinations of 15-second ad versions in the split :30 as proposed in the design. Tape 4 was a control tape in which the second pod contained the two filler commercials followed by only the 15-second target commercial.

Dependent Variables. Each subject was tested by means of an aided recall measure followed by a recog- nition measure. In the recall measure, subjects were provided the product categories of the various com- mercials they had seen and were asked to recall the brand name and claim(sypromise(s) made by the re- spective commercials. For exploratory purposes, we also measured subjects' recognition memory by using sequential two-alternatives forced-choice tests of brand names and claim(s). In each test, subjects were told about the product category represented in the respective commercial and were asked to recognize the brand name from the two alternatives. Next, they were asked to select the correct claim from a set of two claims.

Results

The cell means of brand recall and copy point (or claim) recall are reported in Table 1. Recognition scores are not reported because they showed a ceiling effect. (Brand recognition scores ranged from .88 to 1.00 and claim recognition scores ranged from .86 to 1.00. ANOVA on these scores showed no significant effects). We computed brand recall by using a coding scheme based on prose analysis that allowed partial credit for partial recall. Two judges familiar with the study coded all responses. Inter-rater agreement was estimated to be 93%. Differences were resolved through discussion. Claim recall was verbatim. Sub-

jects received credit only if they recalled the claim

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18 Journal of Adverti8ing

Table 1 Average Recall Scores

Ad-Version Brand Recall Claim Recall Combination SRI LRI SRI LRI

Control Mean: 0.50 0.21 0.29 0.29 (n): (17) (14) (17) (14)

Identical versions 0.34 0.22 0.94 0.20 (16) (20) (16) (20)

Similar versions 0.56 0.19 0.81 0.59 (16) (17) (16) (17)

Different versions 0.59 0.32 0.53 0.57 (17) (23) (17) (23)

SRI - short retention interval LRI - long retention interval

exactly as presented in the commercial. Tables 2 and 3 report the results of ANOVA for

brand recall and claim recall, respectively. As is evi- dent from these tables, the results are mixed. The critical interaction, between ad-version combination (for identical versus different versions) and retention interval, is not significant for brand recall but is sig- nificant for claim recall (p < .05; r2 = .07). Thus, the data provide support for the hypothesized effect.

However, when we include the "similar" version and analyze the data on all three ad-versions together, interaction is not significant for brand recall (p < .464) but it is significant for claim recall at p < .01; r12 = .05. The higher p-value obtained in this case could be directly attributed to a 29% drop in the effect size (from r12 = 0.07 to n2 = 0.05). This, in turn could be attributed to the changes in the executional cues (or contextual changes). In other words, effect size is higher when comparing "identical" and "different" versions only (where the executional cue differences, and hence the contrast in the contexts, is maximal) versus when all three types of commercials are con- sidered.

The interaction effect of ad-version combination and retention interval on claim recall is plotted in Figure 1. All effects relating to the claims are in the hypoth- esized direction. For the short delay condition, the

figure shows a declining pattern in which claim recall is highest for the identical-versions condition followed by the similar-versions condition, and lowest for the different-versions condition. For the long delay condi-

tion, the figure shows an increasing pattern in which claim recall is lowest for the identical-versions condi- tion and higher for the similar-versions and differ- ent-versions conditions. Trend analysis for the data in the long delay condition shows a significant linear trend (p < .10).

The interaction effect of ad-version combination and retention interval on claim recall is plotted somewhat differently in Figure 2 than it is in Figure 1. For Figure 2 we used only the identical-versions and dif- ferent combinations (dropping the similar-versions combination) and plotted the measurement delay on the x-axis.

Contrasting the cell means in a directional t-test shows that in the short retention interval condition, identical versions produced higher claim recall (t=1.59, df=103, p < .10) than different versions. The reverse is true in the long retention interval condition, where different versions outperformed identical versions (t=1.63, df=103, p<.10).

The pattern of memory decay in the two retention interval conditions is even more revealing. There is virtually no memory decay over a 24-hour period for the different-versions condition. However, over the same period, the decline is fairly steep for the identi- cal-versions condition. Indeed, a statistical test shows that the decline in memory is significantly greater for the identical-versions condition than for the differ- ent-versions condition (t=2.84, df=31, p < .05; d =

0.98). These results are virtually identical to those of Singh et al. (1992), who manipulated context by vary-

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Fall 1995 19

Table 2 Analysis of Variance Results for Effect of "Identical" Versus "Different" Ad-Version Combinations and

Retention Interval on Brand Recall

Source Sums of Squares D.F. Mean Square F

Ad-Version 0.469 1 0.469 2.503 Combination

Retention 0.743 1 0.743 3.966' Interval

Ad-Version 0.111 1 0.111 0.591 Combination x Retention Interval

Residual 13.492 72 0.187

Total 14.792 75 0.197

p <.05

Table 3 Analysis of Variance Results for Effect of "Identical" Versus "Different" Ad-Version Combinations and

Retention Interval on Claim Recall

Source Sums of Squares D.F. Mean Square F

Ad-Version 0.016 1 0.016 0.031 Combination

Retention 2.063 1 2.063 4.124a Interval

Ad-Version 2.784 1 2.784 5.564' Combination x Retention Interval

Residual 36.025 72 0.500

Total 40.882 75 0.545

p < .05

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20~~_ Journa ofAderi8

Figure 1 Interaction Effect of Ad-Version Combination and Retention Interval on Claim Recall

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Identical Similar

Short Interval

Long Interval

Different

Ad-Version Combination

ing the number of intervening commercials between the two presentations.

It is important to note that the preceding crossover interaction results depend on the effect of repetition, and repetition has only a small effect on claim recall (W2=.045) and no effect on brand name recall (T2=.0003). (To obtain the effect of repetition, we col- lapsed the cells across retention interval and ad-ver- sion combination for the experimental group and across retention interval for the control group.)

Discussion and Implications

The results demonstrate the presence of crossover interaction between ad-version combination and re- tention interval. In delayed measurement, the de- cline in claim recall was significantly greater when identical versions of a commercial were used in the two halves of a split :30 than when different versions were used. These findings have both theoretical and

practical relevance.

Our findings provide support for the encoding vari- ability theory explanation of the classical crossover interaction between context change and measurement delay. In verbal learning studies, typically the con- textual change is manipulated by increasing or dq- creasing the number of items presented between two presentations of a stimulus item. Thus, the context change is operationalized by manipulating the lag, or number of items between the first and second expo- sures of a stimulus item (Glenberg 1976; Peterson et al. 1963; Sperber 1974). What is unique about our

study is that the lag condition of verbal learning stud- ies was mirrored through a direct change in context via manipulation of message similarity. Crossover interaction was still found, at least for claim recall.

The fact that the predicted crossover interaction is

significant only for claim recall and not for brand recall must be examined within the context of main effects of repetition on brand recall and claim recall. Given that repetition had no significant effect on brand recall and only a small effect on claim recall, it is not

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Figure 2 Interaction Effect of Ad-Version Combination and Retention Interval on Claim Recall for

"Identical" and "Different" Commercials

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Retention Interval

surprising that the crossover interaction is not sig- nificant for brand recall. With this weak effect of repetition, even finding a statistically discernable crossover interaction for claim recall is remarkable. Moreover, this interaction effect, which is modest at the 2=.05 level when all three ad-version combina- tions (identical-versions, similar-versions, and differ- ent-versions) are analyzed together, is much more pronounced when we compare the identical-versions combination with the different-versions combination (q2=.07).

More important is the fact that the results unequivo- cally support the prediction that the decline in memory will be significantly greater for the identical-versions condition than for the different-versions condition. This finding, by providing support for the encoding variability theory, helps us better understand the effect of advertising repetition-a commonly used tech- nique of uncertain utility. Our results support the findings of Singh et al. (1992), who were able to show

a crossover interaction by manipulating the spacing between exposures of a commercial. Our results are also consistent with those of Unnava and Burnkrant (1991), who found that presenting varied ad execu- tions produced higher recall scores than presenting the same ad executions when memory was measured at a delay after the second exposure.

Taken together, our findings and those of Singh et al. (1992) and Unnava and Burnkrant (1991), who used encoding variability theory to explain the effect of varied ad executions, suggest that encoding vari- ability theory is a succinct and powerful model that can be used to explain a number of empirical find- ings. For example, the model can explain Zielske's (1959) finding that spaced presentations lead to bet- ter memory at long retention intervals than massed presentations, in terms of lag effect. Encoding vari- ability theory can be especially useful as a model for explaining advertising wearout effects. Advertising scholars have typically relied on the two-factor theory

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22 Journal of Adverti8ing

(Berlyne 1970) to account for message wearout. Un- fortunately, in advertising, two explicit tests of the two-factor model (Belch 1982; Rethans et al. 1986) have failed to find support for it. As Pechmann and Stewart (1988) point out, we need a new model to explain advertising wearout. Encoding variability theory may be just such a model. It can explain wearout in terms of lack of contextual changes be- tween presentations. Similarly, the model can ex- plain Schumann, Petty, and Clemens' (1990) finding that wearout can be forestalled by using different versions of an ad. According to encoding variability theory, changing the versions changes the contextual information which in turn increases context utiliza- tion, and promotes memory of the ad and forestalls wearout.

Our findings have several practical implications. For example, if an advertiser's goal is to promote message recall after a short interval, the two halves of a split :30 should contain the same commercial. If the goal is to enhance memory over a long interval, using two very different versions of the commercial might be prudent. Generally, advertisers aim for maxi- mizing memory over long intervals (witness the popu- larity of day-after recall measures). Therefore, the latter option seems more suitable for the majority of advertisers.

Creating different versions would certainly add to the cost of producing the ad, but would eliminate the brand-matching problem so common in the split :30 format. In addition to promoting memory, using dif- ferent versions of the message should reduce adver- tising wearout.

According to encoding variability theory, an advertiser's memory enhancement goal would be best served by using two ads representing as varied prod- uct categories and message execution elements as possible. That approach could result in a brand in- compatibility problem as well as the problem of two ads coming across as two quick cuts and evoking negative viewer reaction. The latter problem can be minimized/overcome by creative execution. To the extent an advertiser can overcome the problems asso- ciated with using very different brands in the two halves of a split :30, EVT would support that practice as a preferred strategy for enhancing memory over long intervals.

Our findings and recommendations are based on a laboratory study and although we used naturalistic conditions, future research must verify our results to enhance their generalizability. For example, we used only one split :30 spot relating to only one product

class. Moreover, the commercial used in the study was a rational one. It would be interesting to investi- gate the presence (absence) of crossover interaction with emotional ads in which executional elements are a central part of the message. Furthermore, fu- ture research could employ multiple split :30s to in- vestigate the validity of the EVT over multiple expo- sure conditions in varying pods and programs.

We used EVT as the explanatory mechanism, but other frameworks could be used in future research to develop predictions about identical and different com- mercials. For example, the issue of stimulus redun- dancy (Leigh 1992) among visual and/or verbal in- puts may be relevant in comparing similar and differ- ent commercials. We kept the message attributes the same across all versions of the message; future re- search could explore variations in message attributes. Finally, we did not take into account the issue of increased clutter due to split :30s and its possible negative effects on ad effectiveness. Although the lit- erature provides some evidence about clutter's ad- verse effect on ad effectiveness, more definitive stud- ies using :30s, split :30s, and stand-alone :15s are needed.

References

Belch, George E. (1982), "The Effects of Television Commercial Repetition on Cognitive Response and Message Acceptance," Journal of Consumer Research, 9 (June), 56-66.

Berlyne, D. E. (1970), 'Novelty, Complexity, and Hedonic Value," Perception and Psychophysics, 8 (April) 279-86.

Bower, Gordon H. (1972), "Stimulus Sampling Theory of Encoding Variability," in Coding Processes in Human Memory, A. W. Melton and E. Martin, eds., Washington, DC: Winston, 85- 123.

Craig, C. S., Brian Sternthal, and Clark Leavitt (1976), "Advertis- ing Wearout: An Experimental Analysis," Journal of Market- ing Research, 13 (November), 365-72.

Crowder, R. G. (1976), Principles of Learning and Memory, Hillsdale, NJ: Lawrence Erlbaum Associates.

Cuddy, Lauren J. and Larry L. Jacoby (1982), "When Forgetting Helps Memory: An Analysis of Repetition Effects," Journal of Verbal Learning and Verbal Behavior, 21 (August), 451-67.

Flexser, A. J. and Endell, Tulving (1978), 'Retrieval Independence in Recognition and Recall," Psychological Review, 85 (May), 153-71.

Gay, Verne (1985), 'Marketers Sort Out Shorter Spots," Advertis- ing Age, 56 (November 21), 24.

Glenberg, Arthur M. (1976), "Monotonic and Nonmonotonic Lag Effects in Paired-Associate and Recognition Memory Para- digms,' Journal of Verbal Learning and Verbal Behavior, 15 (February), 1-16.

(1979), "Component-Levels Theory of the Effects of Spacing of Repetitions and Recall and Recognition," Memory and Cognition, 7 (January), 95-112.

Hauser, John R. and Birger Wernerfelt (1990), 'An Evaluation Cost Model of Consideration Sets," Journal of Consumer Re- search, 16 (March), 393-408.

22 Journal of Advertising

This content downloaded from 129.237.57.68 on Fri, 24 Apr 2015 19:07:51 UTCAll use subject to JSTOR Terms and Conditions

Fall 1995 23

Kintsch, Walter (1974), The Representation of Meaning in Memory, Hillsdale, NJ: Lawrence Erlbaum Associates.

Klatzky, Roberta L. (1980), Human Memory: Structures and Pro- cesses, San Francisco: W. H. Freeman & Company.

Leigh, James H. (1992), "Modality Congruence, Multiple Resource Theory and Intermedia Broadcast Comparisons: An Elabora- tion," Journal of Advertising, 21 (June), 55-62.

Madigan, Stephen A. (1969), "Intraserial Repetition and Coding Process in Free Recall," Journal of Verbal Learning and Ver- bal Behavior, 8 (6), 828-35.

Melton, A. W. (1967), "Repetition and Retrieval from Memory," Science, 158, 532.

(1970), "The Situation with Respect of the Spacing of Repetitions and Memory," Journal of Verbal Learning and Verbal Behavior, 9 (October), 596-606.

Murry, John P., John L. Lastovicka, and Surendra N. Singh (1992), "Feeling and Liking Responses to Television Programs: An Examination of Two Explanations for Context Effects," Jour- nal of Consumer Research, 18 (March), 441-51.

Pechmann, Cornelia and David W. Stewart (1988), "Advertising Repetition: A Critical Review of Wearin and Wearout," in Current Issues and Research in Advertising, Vol. 2, James H. Leigh and Claude R. Martin, Jr., eds., Ann Arbor: Division of Research, Michigan Business School, University of Michigan, 285-330.

Peterson, L. R., R. Wamplex, M. Kirkpatric, and D. Saltzman (1963), "Effect of Spacing Presentation on Retention of Paired- Associates Over Short Intervals," Journal of Experimental Psychology, 66 (August) 206-9.

Rethans, Arno J., Jack L. Swasy, and L. J. Marks (1986), "Effect of Television Commercial Repetition, Receiver Knowledge, and Commercial Length: A Test of the Two-Factor Model," Jour- nal of Marketing Research, 23 (February), 50-6.

Sawyer, Alan G. and Dwayne Ball (1981), "Statistical Power and Effect Size in Marketing Research," Journal of Marketing Research, 18 (August) 275-90.

Schumann, David W., Richard E. Petty, and D. Scott Clemens (1990), 'Predicting the Effectiveness of Different Strategies of Advertising Variation: A Test of Repetition-Variation Hypoth- eses,' Journal of Consumer Research, 17 (September), 192- 202.

Singh, Surendra N., Sanjay Mishra, Neeli Bendapudi, and Denise Linville (1992), "Altering Message Spacing to Enhance Memory of Television Commercials," Marketing Science Working Pa- pers Series, Report No. 92-130 (November).

Michael L. Rothschild, and Gilbert A. Churchill, Jr., (1988), "Rec- ognition Versus Recall as Measures of Television Commercial Forgetting," Journal of Marketing Research, 15 (February), 72-80.

Sperber, R. D. (1974), "Developmental Changes in Effects of Spac- ing of Trials in Retardate Discrimination Learning and Memory," Journal of Experimental Psychology, 103 (August) 204-10.

Thomson, D. M. and Endell Tulving (1970), "Associative Encoding and Retrieval: Weak and Strong Cues," Journal of Experi- mental Psychology, 86 (November), 255-62.

Tulving, Endell and D. M. Thomson (1973), "Encoding Specificity and Retrieval Processes in Episodic Memory," Psychological Review, 80 (September), 352-73.

Unnava, H. Rao and Robert E. Burnkrant (1991), "Effect of Re- peating Varied Ad Executions on Brand Name Memory, Jour- nal of Marketing Research, 28 (November), 406-16.

Zielske, H. (1959), "The Remembering and Forgetting of Advertis- ing," Journal of Marketing, 23 (January), 239-43.

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