Source Independence in Multiple Source Advertising Appeals: the Confederate Effect

ABSTRACT - Current explanations for the multiple source effect in persuasion have centered on the information utility hypothesis. According to this hypothesis, a message recipient "needs" to process more diligently information from each of a set of multiple sources because each source may represent a different perspective. In this paper, we discuss some findings that seem to support this hypothesis. We also attempt to clarify the role of source "nonindependence" by contrasting Harkins and Petty's (1987) "committee effect" with a "confederate effect."

Citation:

David J. Moore, Richard Reardon, and John C. Mowen (1989) ,"Source Independence in Multiple Source Advertising Appeals: the Confederate Effect", in NA - Advances in Consumer Research Volume 16, eds. Thomas K. Srull, Provo, UT : Association for Consumer Research, Pages: 719-722.

Advances in Consumer Research Volume 16, 1989      Pages 719-722

SOURCE INDEPENDENCE IN MULTIPLE SOURCE ADVERTISING APPEALS: THE CONFEDERATE EFFECT

David J. Moore, University of Michigan

Richard Reardon, University of Oklahoma

John C. Mowen, Oklahoma State University

ABSTRACT -

Current explanations for the multiple source effect in persuasion have centered on the information utility hypothesis. According to this hypothesis, a message recipient "needs" to process more diligently information from each of a set of multiple sources because each source may represent a different perspective. In this paper, we discuss some findings that seem to support this hypothesis. We also attempt to clarify the role of source "nonindependence" by contrasting Harkins and Petty's (1987) "committee effect" with a "confederate effect."

INTRODUCTION

Professionals who make their living persuading others to buy a product or vote for a candidate have long used multiple source techniques (e.g., multiple endorsers) to enhance the impact of their persuasive appeals. Harkins and Petty (1981a, 1981b, 1987), and colleagues, have used an information processing framework to try to explain the effect. The information processing approach holds that a persuasive appeal is strongest when it operates to stimulate recipients' motivation and/or ability to think about the attitude issue (Petty and Cacioppo 1986). Specifically, it has been argued that multiple sources act to facilitate a high level of motivation to engage in issue-relevant processing. That multiple sources are more effective than a single message source in stimulating message recipients to process information has been reported in a series of experiments by Harkins and Petty (1981a, 1981b).

Harkins and Petty (1987) suggest that information utility may be behind the enhanced processing that is stimulated by multiple source presentations. The message recipient, when exposed to multiple sources each presenting unique arguments, presumably perceives these different arguments as independent bits of information coming from individuals with different perspectives and backgrounds. Because information processing is in the service of prediction and control, subjects should be highly motivated to process these arguments with greater interest and diligence. In contrast, when several arguments are delivered by a single source, message processing may be reduced since the target may feel that s/he has already heard from this particular source perspective; as the arguments occur, the subject feels s/he can predict later arguments from earlier ones, and can begin to "tune out."

Consistent with this hypothesis, Harkins and Petty (1987) found that the multiple source effect was eliminated when the sources were said to be members of the same committee (i.e., the "committee effect"), as opposed to when the sources were represented as being independent of each other. A committee can be assumed to reflect a single informational bias. Therefore, a message presented by multiple sources representing the supposedly unified views of a single committee should stimulate no additional processing, and thus no greater persuasion than a message presented by a single source.

In this paper, we will explore further the multiple source effect. We will present summaries of two research projects that bear on the informational utility hypothesis, and we will conclude with a preliminary report of research into nonindependence due to the "confederate effect."

SOURCE-TARGET SIMILARITY

One "bounds condition" on the multiple source effect' that may be enlightening with respect to the information utility hypothesis concerns the perceived similarity of sources to the target. It follows from the information utility logic that multiple source effects should be minimized when the multiple sources are similar to the target. When the sources are dissimilar, as each source appears, that source's arguments provide no reliable clue to the positions/arguments of later sources. On the other hand, when the sources are assumed to be similar, a recipient may feel s/he can predict what later sources will say, and thus the later information has less utility (and the recipient's motivation to process arguments from the later sources may decline).

In Clark, Romero, Elam, and Reardon (1988), we reported some preliminary findings that seem to confirm the existence of a source-target similarity boundary condition on the multiple source effect. Half of the subjects in this study received four arguments in favor of a national gasoline sales tax from a single source; the other half received the same four arguments from four sources, one argument from each source. Crossed with the number of sources variable was a manipulation of the perceived similarity of the sources to the target. Half of the subjects in each of the number of sources conditions were told that the sources were fellow students from the psychology subject pool; the other half were told that the sources were from all over the country, and varied in age and occupation. Consistent with previous literature, more thought was associated with multiple sources. In particular, there was a tendency to list more issue supportive thoughts in response to four dissimilar sources.

MULTIPLE SOURCES AND MULTIPLE ISSUES

In Reardon, Moore, and Young (1988), we were interested in the effects of multiple sources over a number of issues. Do subjects believe they learn enough about their sources of information over several issues to make predictions about what the future viewpoints of the sources are going to be? If so, then the multiple source effect may be attenuated with later issues (relative to earlier ones) as motivation to process declines (because the information has less utility). If not, the effect should persist across issues. In a sense, we were looking for the development of the perception of interdependence. We looked at one vs. four sources, who were either the same or different within each issue and across issues.

The issues were (a) senior exit exams, (b) location of a toxic waste site near campus, (c) a university library surcharge fee, and (d) divestiture by the University of South African investments. For half of the subjects, four arguments came from a single source; the other half received the same four arguments from four sources, one argument from each source. Crossed with the number of sources variable was a similarity variable. For half of the subjects in each number of sources condition, the sources (whether one or four) were the same from issue to issue; for the other half, the subjects received either a different source with each issue, or a different set of sources with each issue.

Our findings for both attitude scale and thought listing measures revealed persuasive effects that, relative to single source conditions, persisted across issues in multiple source conditions. However, consistent with hypotheses, there was some moderation of the effect when the four sources were the same from issue to issue.

Neither Clark et al. (1988) nor Reardon et al. (1988) directly addressed source independence/ nonindependence. Nonetheless, they did provide important support for the information utility hypothesis in contexts separate from the independence/nonindependence issue. Thus, in proposing a different pattern of subject response to nonindependence than that outlined by Harkins and Petty, our focus was more toward accounting for both patterns in terms of the information utility hypothesis than in suggesting a rival hypothesis.

THE CONFEDERATE EFFECT

Harkins and Petty's (1987) "committee effect" clearly represents a kind of nonindependence of sources. However, sources may also be independent of one another, yet still reflect a common information bias by virtue of the influence exerted over them by an outside force; and recipients may be quite aware of this nonindependence. For example, even if product endorsers featured in "person-on-the-street" interviews are perceived as independent of each other, the persuasive impact of their testimony might be significantly diminished because it appears to the recipients that the sources have been monetarily compensated by the advertiser (Harkins and Petty 1983). In contrast to a "committee effect," we might call this a "confederate effect" because the sources may be perceived as confederates of an unobserved agent.

Logically, the persuasive advantage of multiple sources versus a single source may be significantly diminished if message targets attribute the reason for the product endorsement to the money the endorsers are paid rather than the endorsers' genuine feelings about the product. A message presented by a single source who is perceived to be independent of (i.e., not paid by) the message sponsor may be perceived to be more credible. Accordingly, this message should warrant more diligent processing than a similar message presented by a single source who is perceived to be biased because s/he is known to be paid for endorsing the product by the sponsoring company.

Essentially, the end products of the "committee effect" and the "confederate effect" are the same: Maximum persuasion with multiple, independent sources. Yet the information utility hypothesis, which, as noted above, has received support within other paradigms, must be able to account for the confederate effect as well as the committee effect. How might it do so? As a result of "committee" deliberation, a message recipient presumably believes s/he is able to predict other members' responses after being presented with one member's response. Multiple sources become, in effect, a single source in terms of a recipient's perceptual field. There is less persuasion because there is less cognitive generational activity.

This may not be the case with a confederate manipulation. Because the message sources are not involved with each other directly, respondents may not perceive of them as a single perceptual unit (Wilder 1978). Thus, there should be a significant increase in cognitive generational activity in both the independent and nonindependent multiple source conditions. However, there will still be less persuasion in the confederate conditions because the increase in generational activity will be in a negative direction (i.e., an increase in negative thoughts).

An attributional discounting factor (Kelley 1973) may be operating to spur further continued cognitive activity in the unpaid conditions. Sparkman (1982) found that when the underlying cause for a spokespersons's testimony was easily attributed to financial compensation by the message sponsor (vs. attributes of the product), there was a tendency to actively consider this alternative causal factor in the evaluation of the message. The valence attached to this consideration is typically negative: Sparkman (1982) found significant decreases in message recipients' evaluation of the believability and trustworthiness of the spokesperson.

We have collected some relevant data (Moore, Reardon, and Mowen 1988). We predicted that subjects who were exposed to independent multiple sources would generate a greater number of positive responses to an advertisement than subjects who were exposed to paid multiple sources. Furthermore, subjects exposed to paid multiple sources were expected to produce a greater number of negative responses than those exposed to a single paid source. Hence, a polarization of thoughts and attitudes was expected to occur in the multiple source treatment conditions. Two variables were manipulated: Type of message endorser (unpaid versus paid by the message sponsor) and number of sources (one versus four).

The results showed the predicted polarization of cognitive responses. Compared to the single source conditions, multiple sources yielded more positive thoughts when the sources were thought to be unpaid, and fewer positive thoughts then the sources were thought to be paid. For negative thoughts, a pattern of results occurred that was conceptually similar to that found for positive thoughts. Compared to the single source conditions, multiple sources yielded fewer negative thoughts when the sources were thought to be paid.

Scale measures of attitudes toward the brand and ad showed that, in multiple source conditions, subjects were more positive toward the product when the source(s) was/were assumed to be unpaid and were more negative when the source(s) was/were assumed to be paid. There was no such difference in the single source conditions.

CONCLUSION

On the basis of the information utility hypothesis, Harkins and Petty (1987) found that exposure to nonindependent sources (e.g., the committee manipulation) eliminated the motivation to process the message and diminished the persuasive advantage of multiple sources. For this reason, the authors concluded that the perceived independence of the message sources is a necessary prerequisite for the occurrence of the multiple source effect. Harkins and Petty argued that the committee manipulation reduces persuasion because subjects put less effort into processing a message presented by nonindependent sources.

Clearly, some of the assumptions associated with the committee effect are not relevant to the confederate effect. Our results indicated that the motivation to process a message can increase rather than cease when message recipients are exposed to multiple, nonindependent sources. There was a significant increase in the generation of both negative and positive thoughts in the paid and unpaid multiple source conditions, respectively. Presumably, the increased attention stimulated by multiple sources serves to activate negative causal attributions when the endorsers are paid for their testimonies, and positive attributions when the sources are unpaid (Sparkman 1982, Kelley 1973). These findings are generally supportive of the information utility hypothesis, but they also suggest a broader interpretation of "information utility."

In their attempt to explain the underlying causes of the multiple source effect, Harkins and Petty (1987) put forward two rival positions: The information-utility account and the attention-focus account. According to the latter, it is the novelty of multiple sources that stimulates increased message elaboration. Therefore, exposure to nonindependent sources should stimulate rather than eliminate increased processing since it is the novelty of the multiple sources that sustains the attention of the audience. Since Harkins and Petty (1987) found no support for this proposition, the attention account was rejected.

To a significant extent, our results support a broadening of the information utility hypothesis to include the attention focus account. Novelty can be an important cue in determining the utility of information. Prior research seems to provide support for this line of reasoning. For example, cognitive psychologists and social cognition specialists have noted that prominent features and/or changes in the perceptual (and socio-perceptual) field command attention. This attention has survival value. The prominent and/or changed features require more careful cognitive consideration because they provide information about whether the perceiver can return to procedure-as-usual (i.e., return to automaticity), or must continue with greater cognitive consideration (Taylor and Fiske 1978, Taylor and Crocker 1981, Klatzky 1984, Jolly and Reardon 1985).

In multiple source conditions using a committee manipulation, it is true that the faces are novel. However, the arguments are not novel; they are predictable; continued attention and elaborate processing are unnecessary. With a confederate manipulation, the faces are novel. However, the arguments may also be novel and thus not predictable; continued attention and elaborate processing are necessary.

REFERENCES

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Moore, D.J., R. Reardon, 1E J.C. Mowen (1988), The Confederate Effect: The Role of Non-Independent Multiple Sources in Advertising Appeals, Unpublished manuscript, The University of Oklahoma.

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