Social Influence and Persuasion 1 Social Influence and Persuasion: Recent Theoretical Developments and Integrative Attempts Hans-Peter Erb University of Chemnitz and Gerd Bohner University of Bielefeld Final draft of Erb, H.-P., & Bohner, G. (2007). Social influence and persuasion: Recent theoretical developments and integrative attempts. In K. Fiedler (Ed.), Social communication (pp. 191-221). New York: Psychology Press.
Social Influence and Persuasion 2 Author Note Hans-Peter Erb, University of Chemnitz, Economical, Organizational and Social Psychology, Wilhelm-Raabe-Str. 43, D-09107 Chemnitz, Germany. Gerd Bohner, University of Bielefeld, Social Psychology, PO-Box 100131, D-33501 Bielefeld, Germany. Electronic mail may be sent to hans-peter.erb@phil.tu-chemnitz.de or gerd.bohner@uni-bielefeld.de. We would like to thank Gerald Echterhoff and Justin Preston for their helpful comments on a previous draft. Keywords (19): Social Influence, Persuasion, Normative Influence, Informational Influence, Minority Influence, Majority Influence, Elaboration Likelihood Model, Heuristic-Systematic Model, Unimodel, Conversion Theory, Leniency Contract Model, Consensus, Objective Consensus Approach, Mere Consensus Approach, Social Identity, Deindividuation, Subjective Relevance, Processing Effort, Motivational Bias
Social Influence and Persuasion 3 INTRODUCTION The study of social influence phenomena lies at the very heart of social psychology. Allport s (1935) classical definition of social psychology as the study of how individuals are influenced by the real or imagined presence of others may be indicative of how crucial social psychologists have regarded influence for all aspects of social life. In fact, social influence occurs constantly. Consider our daily exposure to radio and television commercials, newspaper ads, direct requests, influence attempts by salespersons, politicians, and so forth. In a broader sense, influence by other individuals operates in many other forms of social interaction as well, including helping behavior, aggression, social loafing, social facilitation, leadership, obedience, prejudice, and many others. In the present chapter we start with a classic distinction between two types of social influence: normative and informational. We will then use this distinction as a guiding principle for reviewing developments in two major areas of research: Social influence in groups, which is mostly captured in terms of minority and majority influence, and persuasion. This focus, necessary with regard to space constraints, has resulted in the omission of a number of other, equally important, approaches to social influence that are less congenial to the structure we decided to present cf., Cialdini s (1994) work on influence tactics (see also Cialdini & Goldstein, 2004), or Latané and Nowak's (1994) application of catastrophe theory to social influence processes. We will conclude this chapter by arguing that abstractions from surface characteristics in social influence and persuasion and a focus on underlying principles can provide new insights and perspectives on the phenomena reported here. NORMATIVE AND INFORMATIONAL INFLUENCE Research on how the social context may influence subjective beliefs and attitudes has by and large centered on two domains: Attitude change in response to persuasive communication as opposed to influence in social groups. Persuasion research has typically focused on the cognitive mechanisms underlying judgment in response to communication while tending to neglect the
Social Influence and Persuasion 4 social context in which such communication takes place. Research more sensitive to interpersonal and group dynamics has predominantly focused on the social contexts of judgment formation, but tended to be inarticulate regarding the underlying cognitive mechanisms. At surface level, the distinction between those two domains resembles the separation between normative and informational influence introduced by Deutsch and Gerard (1955). Since its inception, Deutsch and Gerard s (1955) dual-process distinction has been one of the most important schemes to guide research on social influence. Normative influence has been assumed to be associated with little or no issue-related processing. As the social relationship between the influence source and its target becomes the focal concern, influence results in mere conforming (Deutsch & Gerard, 1955) or compliance (Moscovici, 1980) at the expense of concerns with the true value of the attitude object. Surveillance of the target by the source has been conceptualized as the critical momentum producing normative influence. As long as the socially valued influence source is present, the target will comply in public. As soon as surveillance ends, for example when the target is allowed to express its attitude in private, attitudes will fall back to their pre-influence value, because the initial change to the publicly expressed opinion has not carried over to a change in the target s true beliefs on the attitude issue. In informational influence, on the other hand, the target is assumed to be free to comply or not because the social implications of her or his attitudes are less relevant. If influence occurs, then, it is supposed to be based on the processing of information related to the issue under consideration. Such agreeing (Deutsch & Gerard, 1955) or conversion (Moscovici, 1980) has often been regarded as true attitude change. This change could be found in private attitude judgments and even when the influence source was no longer present; it persisted over time, resisted counter-argumentation, and often generalized to issues that were not identical but somehow related to the focal issue of influence. Attitude change on the basis of issue-related information (such as arguments) typically
Social Influence and Persuasion 5 has been the major concern of persuasion research, which we will review in more detail below. Presently it suffices to recall that dual-process models of persuasion (Chaiken, Liberman, & Eagly, 1989; Petty & Cacioppo, 1986a, 1986b) distinguish between two qualitatively different processes of attitude formation and change. In a rather simple and effortless process, the targets of persuasive appeals may use shortcuts and simple heuristics (e.g., experts can be trusted, high consensus implies correctness ) to form their attitude judgments. Only when motivation and ability to process information are high, recipients engage in a more effortful process and consider mainly issue-related information such as the arguments presented. Such processing of the true merits (Petty & Wegener, 1999) of the issue is mostly concerned with what was called informational influence. On the other hand, influence based on the normative value of a given influence group, often in the absence of any issue-related processing, was treated as a peripheral or heuristic process (e.g., Baker & Petty, 1994) and was regarded as no different from other peripheral mechanisms such as the use of source expertise or one s current mood for judgment formation. SOCIAL INFLUENCE IN GROUPS Seminal Studies For a long time, social influence in groups was understood as the psychology of conformity, often represented in the influence that the majority exerts on an individual. In Sherif s (1935) studies, for example, individuals were exposed to an ambiguous stimulus situation, and they took into account the judgments of others as a source of information about the true value of the object to be judged (the assumed movement of a light spot). Other than Sherif (1935), Asch (1956) used fully unambiguous stimuli in his line-judgment experiments. Influence still occurred, presumably because individuals were concerned with the impression others might form of them. This (rather simplified) distinction between influence in Sherif s versus Asch s
Social Influence and Persuasion 6 paradigms may serve as a prime example of informational versus normative influence (Deutsch & Gerard, 1955). In informational influence, individuals use the information provided by others as a source of the true value of the object under consideration. Normative influence, on the other hand, refers to the individual s assumed need to align their attitude with that of some valued other(s), be it a single person (e.g., one s spouse) or a reference group. From this perspective, the Sherif paradigm reflects informational influence: The informational basis for the judgment is obscure, and others judgments will be regarded as information on the true value of the light s movement. In the Asch paradigm, however, information on the true value is straightforward (one s visual perception provides a usually valid source of information), but others judgments are in contradiction to the informational basis. It may seem that whenever others judgments prevail over the informational basis, normative influence is at operation. Normative Influence and Social Identity In more recent theorizing, normative influence in Deutsch and Gerard s sense is closely related to Social Identity Theory (SIT; e.g., Tajfel, 1981; Tajfel & Turner, 1986) and its central concept, self-categorization (e.g., Turner, Hogg, Oakes, Reicher, & Wetherell, 1987). According to SIT, group membership is of fundamental concern to the individual because it determines the individual s self-definition and social identity. Thus, group membership has important implications. Relevant to the present discussion, opinions held by an individual do not only reflect knowledge about an issue, they also reflect something about the individual s self, as conformity with a group s opinion means adopting the group s identity. Dissent with a selfrelevant group s attitude will urge the individual to resolve the disagreement, especially if shared attitudes are a group-defining feature (Turner, 1991). This is not to say that any selfdefining group is monolithic in its demands for within-group consensus on every issue. Still, it seems straightforward to predict that identity-defining in-groups exert social influence on the individual, whereas influence by out-groups can more easily be refuted (e.g., Crano, 2001;
Social Influence and Persuasion 7 David & Turner, 2001). Thus, identification is assumed to be a prerequisite of social influence. Yet SIT and its derivatives (e.g., Spears, Postmes, Lea, & Watt, 2001) do not ignore the role of issue-related information as an informational basis of social influence. In terms of SIT, the group is particularly important because it provides social validation of individual attitudes. It is the recipient s relation to the source that defines how the message is perceived. From the perspective of SIT, intra- and inter-group relations thus cannot be relegated to the status of a peripheral variable, but lie at the heart of any influence situation. The distinction between normative and informational influence can thus be regarded as a guiding principle in research into social influence and persuasion. Persuasion researchers theoretical focus was on informational influence, specifically message learning (Hovland, Janis, & Kelley, 1953) or cognitive responding to persuasive messages (Petty, Ostrom, & Brock, 1981), whereas source variables were assigned peripheral status. Research on group-based social influence, on the other hand, has been mainly concerned with the psychological consequences of being in a group and its effects on judgment formation, with the meaning of issue-related information playing the less important role and being seen as dependent on whether its source was a self-defining group or not. Conversion Theory We now turn to a model that integrates normative and informational influence by distinctly allocating informational influence to social minorities, and normative influence to social majorities. Moscovici s (e.g., Moscovici, 1980) conversion theory (CT) has been one of the most important models in social influence during the last decades. It would be impossible to understand the most recent advances in research on social influence without discussing how they relate to Moscovici s seminal work (see also Martin & Hewstone, 2001). Research in the tradition of Asch (1956) and Sherif (1935) focused on the effect that a majority of others has on individual judgments. The question of what conditions foster
Social Influence and Persuasion 8 conformity thus dominated research into social influence for a long time (see Jones & Gerard, 1967, for a review). Despite the immense power of social consensus, however, history provides many examples of the opposite, namely, opinion minorities that exerted considerable influence, for example the civil rights movement in the U.S. or the environmentalist movement in Europe. Moscovici (e.g., Moscovici, Lage, & Naffrechoux, 1969) was the first researcher to acknowledge that at times minorities, who by definition hold positions of low consensus, can be influential. In CT, Moscovici (1980) distinguished two qualitatively different processes associated with majority and minority influence. He incorporated the distinction between normative and informational influence, and made predictions with regard to cognitive effort in processing issue-relevant information that mapped on the distinction between systematic or central route processing and heuristic or peripheral route processing that were developed in research on persuasion at roughly the same time. According to CT, minorities and majorities exert influence in qualitatively distinct ways. When confronted with majority influence, the individual experiences a social conflict. This conflict revolves around the question of why she or he sees things differently than most others. Reactions to this conflict focus on the social relationship between the individual and the influence group at the expense of issue-related processing. This is because the power of a majority resides in its ability to punish and reward group members. Deviance is regarded as leading to negative consequences, and the individual in disagreement with the majority s position is likely to experience discomfort. To solve this stressful social conflict, the individual agrees with the majority position in public. But given that such compliance is not backed up with issue-related processing, attitude change in the case of majority influence is superficial and short-lived, does not generalize to related issues, and vanishes as soon as the source of influence is no longer present. Majority influence according to CT is clearly an example of normative influence in Deutsch and Gerard s (1955) sense, and also an example of attitude change on the
Social Influence and Persuasion 9 basis of low-effort processing when viewed from dual-process models of persuasion. Minorities, on the other hand, lack the power to reward or punish. The target who is in conflict with a minority source, therefore, does not experience discomfort. The minority lacks the ability to exert influence based on sheer power. Its only chance of exerting influence is by making a virtue out of necessity and trying to convince others based on content related arguments. To do so, it has to display a consistent behavioral style. That is, to repeat its position unanimously as often as possible. Such consistency has two consequences: first, conflict produces a climate for social change. Other than in majority influence, such conflict is not social in nature but cognitive, as it relates to the controversial issue and the question of what is wrong and what is right. Second, the target ascribes confidence in their position to the minority members. In turn, the target engages in a validation process by which she or he considers the minority position carefully. Often, validation will not lead to direct, immediate, or publicly announced change. Because of the majority s power, the target is reluctant to align in public with the minority. In private, however, the target attempts to understand the deviating position and reevaluates her or his initial attitude. Validation results in conversion, a slow but constant change towards the minority position based on issue-related considerations. As such, conversion reflects informational influence in Deutsch and Gerard s (1955) sense, and high effort processing of issue-related information when viewed in terms of dual-process models of persuasion. Moscovici s (1980) CT had an extremely energizing effect on research into social influence phenomena. Empirical tests of CT, however, yielded mixed results. In a meta-analysis, Wood, Lundgren, Ouellette, Busceme, and Blackstone (1994) found greater influence of majority than minority sources on both public and private direct measures. In addition, minorities did not exert greater impact in private than in public. In favor of CT, however, minority influence was greater when assessed indirectly on issues related to the focal issue as
Social Influence and Persuasion 10 compared with direct measures of attitude change. Yet, even on indirect measures minorities did not exert reliably greater influence than did majorities. Overall, then, minorities were found to exert less influence than majorities (Wood et al., 1994). The status of CT s hypothesis that minorities instigate more effort in the processing of their messages than do majorities is not much clearer. By contrast, Mackie (1987) found that participants invested more effort in processing majority than minority messages. According to her objective consensus approach, the majority s high consensus implies correctness and therefore directs attention to the majority s message. Baker and Petty (1994) demonstrated that both minorities and majorities may instigate careful processing of their messages if the position they favor is unexpected: If a majority of students favored, or a minority opposed, a mandatory social service for students, this obvious source-position imbalance generated surprise which in turn increased processing effort. Erb, Bohner, Schmälzle, and Rank (1998) were the first to employ control conditions where no source information was provided and found that targets invested less effort in processing both minority and majority messages compared with the control condition. In this study, the influence group was socially irrelevant to recipients who held no prior attitudes, so that conflict in Moscovici s sense was not in operation. Under these conditions recipients simplified judgment formation by using consensus information as an indicator of message validity. Hence, influence targets were inclined to invest more effort in messages not attached to consensus information, where such a pre-judgment could not be generated. Despite the overall mixed empirical support for CT, many recent developments in the field refer to CT in one way or another. For example, work by Nemeth and her colleagues (e.g., Nemeth, 1986; Peterson & Nemeth, 1996) alludes to Moscovici s idea of differential conflict under minority versus majority influence. According to Nemeth, dissent with a majority induces pressure to comply, whereas dissent with a minority does not. It follows that, under majority
Social Influence and Persuasion 11 influence, individuals focus their attention on the information provided in the situation, reflecting convergent thinking. Under minority influence, on the other hand, the individual is free to deal with the issue under consideration in her or his own terms. This results in divergent thinking, a processing mode in which the target of influence considers self-generated novel information in a creative manner. Drawing on the heuristic-systematic model of persuasion (Chaiken et al., 1989) Moskowitz (1996; Moskowitz & Chaiken, 2001) proposed that positive attributions toward the minority or other conditions such as surprise motivate recipients to systematically process the minority s arguments (see also Baker & Petty, 1994; De Vries, De Dreu, Gordijn, & Schuurman, 1996). These recent approaches relate to Moscovici s idea that minority influence rests on the careful processing of issue-related information. Yet, they deny that a source s minority status in itself suffices for motivating targets to process their message thoroughly. In addition, they hold that mere processing of minority arguments does not necessarily lead to attitude change. Indeed, attitude change depends on the quality of the arguments presented: Only strong and convincing arguments, when processed, will produce attitude change in the intended direction, whereas weak arguments will not (see Bohner, Moskowitz, & Chaiken, 1995). Integrative Attempts The Leniency Contract Model A recently developed integrative theory is the leniency contract model (Alvaro & Crano, 1997; Crano, 2001; Crano & Chen, 1998). It is of particular interest here because Crano and his colleagues expanded CT by integrating assumptions of SIT (Tajfel, 1981) and dual-process theories of persuasion (Chaiken et al., 1989; Petty & Cacioppo, 1986a, 1986b). As a result, their model contains aspects of both informational and normative influence. A major stipulation imported from SIT-based research on social influence (e.g., David & Turner, 2001) is that majority or minority messages impact hinges on the identity-relevance of both the source (is it
Social Influence and Persuasion 12 in-group or out-group?) and the topic (is it group-defining?). Only in-group sources are considered as relevant influence agents, because accepting or rejecting their message may have consequences for the individual s standing within the group. If an influence target perceives a counterattitudinal position within its in-group, the following chain of events is set in motion. If the source is a majority, the target will check if the source s position is legitimate, that is, whether it is central to group concerns: If it is not, the target may ignore or dismiss the majority message. If, however, the message pertains to a central, group-defining topic and is counterattitudinal, the target will experience threat and will be motivated to process the message with high effort. Depending on the quality of message arguments, this effortful processing may lead to either short-term change (if arguments are weak) or long-term change on the focal issue (if arguments are strong). The latter prediction is partly in line with dual-process models of persuasion; viewed from their perspective, perceived identity-relevance of the majority message increases the motivation to process that message with high effort. In this respect, the leniency model prediction deviates from conversion theory, which does not provide for content elaboration or long-term attitude change in response to majority influence. In another respect, however, the leniency contract model converges with conversion theory: Majority influence is not assumed to generalize to related issues. This is because elaboration of the majority message is seen as motivated by the need to fit in, not to extract the gist of the message (Crano, 2001, p. 137). A different situation arises if the source is an ingroup minority. Whether legitimate or not, a minority message will always be perceived as novel and unexpected. If its position is seen as threatening the existence of the group, the minority is likely to be ostracized and thus become viewed as an out-group; its message may then be ignored or derogated (cf. Festinger, 1950). If the minority s position does not threaten group concerns, however, majority members will be open to considering the minority s arguments. This is where the leniency contract comes into
Social Influence and Persuasion 13 play. Majority members will elaborate the minority s arguments with leniency and refrain from counterarguing. In exchange for this tolerant treatment of the minority, it is tacitly understood that the majority will not change its position on the focal issue. The leniency contract thus provides a mechanism by which groups may permit some degree of variance in expressed opinions while maintaining coherence and positive relationships within the group. At the cognitive level, however, the open-minded elaboration of the minority message has an unintended effect: It creates pressure toward change, not in the focal attitude (which is contractually protected from change), but in other, related attitudes, which are linked to the focal attitude through the spreading of activation in a cognitive network (Anderson & Bower, 1973). The result is indirect attitude change, which may further lead to delayed focal attitude change, especially if the message arguments are strong. The complexity of these assumed mechanisms may explain why findings in the minority influence literature are relatively mixed in terms of the levels and time delays at which attitude change has been observed (Wood et al., 1994). Empirical evidence for the leniency contract model mainly comes from two publications: The first is a paper by Alvaro and Crano (1997) which identified two attitude issues that were related according to a multidimensional scaling of attitude judgments: gay men in the military and gun control. Importantly, however, participants did not perceive the two issues to be related if asked whether change in one attitude might lead to change in the other. Students exposed to an in-group minority message arguing against gay men in the military showed no focal change on this attitude object; they did, however, become more opposed to gun control, thereby showing indirect attitude change in line with the conservative appeal of the anti-gay message. In a follow-up study, Alvaro and Crano reversed the roles of focal and related topic and found comparable results. In neither of these studies did in-group majority messages have any impact on participants attitudes, presumably because the message topics were not identity-relevant to university students as a group.
Social Influence and Persuasion 14 Crano and Chen (1998, Study 3) further provided some correlational evidence for the assumption that indirect attitude change may be followed by focal change after some delay. In their study, students read a minority or majority message arguing for a mandatory, unpaid university service for students (obviously a counterattitudinal position). Later, the students attitudes toward this focal issue and a related issue (tuition increase) were assessed both immediately and after one week. Analyses within the recipients who had been exposed to a minority position revealed that those students who showed greater immediate indirect change also showed greater delayed focal change. Overall, however, focal posttest attitudes did not differ from pretest levels for minority influence. In this study, unlike in Alvaro and Crano (1997), majority messages did affect students attitudes at both immediate and delayed tests. This is in line with the leniency model s hypothesis that majorities will exert substantial impact if the issue is group-defining. Although empirical evidence for the model s predictions is somewhat limited, the leniency contract model provides an interesting extension of conversion theory. It integrates the largely disparate theoretical traditions of social influence and persuasion research and specifies the interplay of normative and informational aspects, thereby generating a number of new predictions. Crano and his colleagues further introduced a novel empirical paradigm, including a quantitative technique, based on multidimensional scaling, for deriving well-defined indirect attitude objects, thus opening an avenue for greater precision in studying social influence at the private, indirect level an issue of some concern in previous literature reviews (e.g., Wood et al., 1994). Other aspects of the leniency contract model, however, seem to warrant critical investigation. First, is it plausible to assume that a social agreement as complex as the leniency contract would operate at a fully unconscious level? To further support this idea, it would be useful if specific evidence for the presence of leniency on the one hand and the proposed lack of
Social Influence and Persuasion 15 couterarguing on the other could be provided. It might also be useful to explore potential links to other theories of implicit social cognition (e.g., Greenwald et al., 2002). Secondly, some of the stages in the chain of events that is assumed to be set in motion by encountering a counterattitudinal in-group message have not been empirically tested yet. For example, would in-group minorities that present group-threatening positions indeed routinely be excluded? According to Festinger s (1950) theory of informal social communication, pressure toward communicating with the deviant group members would be an alternative result of encountering a threatening minority, whereas the expulsion of deviant group members might constitute only the ultima ratio if communication failed to restore group consensus. Finally, in attempting to subsume a broad range of phenomena under a common theoretical umbrella, Crano and his colleagues have specified a rather complex array of conditions, such that their theory may lack the parsimony needed for a general model of social influence. In the next section, we present our own attempt at formulating a more parsimonious general model. The Mere Consensus Approach We propose to reduce scientific explanation of the phenomena reported in social influence research to the operation of a single variable, namely consensus. Thus, our mere consensus approach (Erb & Bohner, 2001, 2006) often provides a more parsimonious explanation for these phenomena than do other models. It builds on the assumption that consensus is the defining feature of minorities and majorities in any context (see also Kruglanski & Mackie, 1990). A majority necessarily reflects higher consensus on a given issue than does a minority. Defining minorities and majorities by consensus alone, we deliberately exclude other variables that have been treated as explanatory constructs in other models. In empirical research, we found that consensus had a number of effects on information processing and judgment formation, even under the impoverished conditions used in our studies, where recipients were provided with consensus information independent of any effect of social conflict, tendencies to
Social Influence and Persuasion 16 identify with the influence group, social power, and so forth (e.g., Erb et al., 1998). Consensus information biased the processing of issue-related information, causing more favorable thoughts under high consensus and less favorable thoughts under low consensus, compared with control conditions where no consensus information was provided. Moreover, mere consensus influenced the divergence versus convergence of cognitive responding (cf. Nemeth, 1986). Under low consensus, respondents came up with new and original ideas about the issue that diverged from the information presented, whereas under high consensus, their processing focused more narrowly on the information presented in the influence setting. Going beyond Nemeth s theorizing, where dissent between recipients attitudes and the influence group s position was assigned major explanatory relevance, our studies showed that consensus that was completely detached from prior attitudes proved to be sufficient to affect the divergence of thought. In sum, this research demonstrated that consensus itself detached from other variables formerly proposed to shape minority and majority impact produces evaluative and cognitive consequences. As such, mere consensus effects can be used as a starting point to analyze the impact of other variables previously examined in the realm of minority and majority influence. One such variable is social conflict, defined as an opinion discrepancy between the position held by the target of influence and the position proposed by the influence source. Social conflict has been accorded major explanatory relevance in Moscovici s (1980) CT (see above). Still, conflict may be present in a social influence situation to a higher or lower degree and at times may be completely absent. We (Erb, Bohner, Rank & Einwiller, 2002) hypothesized that the absence of conflict may be the reason why Mackie (1987, see above) consistently found that majorities instigated targets to invest more processing effort than did minorities. According to Mackie s objective consensus approach, the majority position is accepted as reflecting objective reality (Mackie, 1987, p. 42) and is much more likely than the minority position to be translated from mere opinion into social reality. Consequently, a recipient s attention will be directed to the
Social Influence and Persuasion 17 majority message, which results in extensive processing of that message. A minority, on the other hand, lacks objective consensus. Hence, as it appears to make no sense to waste cognitive energy on processing a position which is likely to be incorrect, the minority message will be processed less extensively. Seemingly, the objective consensus approach is difficult to reconcile with Moscovici s CT where minority influence was expected to produce more extensive message processing. The contradiction between Moscovici s (1980) and Mackie s (1987) findings points to the possibility that moderating factors need to be taken into account (Wood, et al., 1994, p. 337). In doing so, we speculated that the attitudes used in Mackie s experiments were probably not related to strong convictions on the part of recipients. The issues (e.g., the U.S. should act to ensure a military balance in the Western hemisphere ) were relatively unfamiliar to participants; the situation was therefore not likely to induce strong conflict when compared with situations where one s own perceptual ability or deep concern with environmental issues are challenged (cf. Moscovici, 1980). In other words, we predicted consensus to interact with recipients prior attitudes in its effect on the level of message processing. Our studies showed that recipients who held a strong attitude that was in conflict with the forwarded position dedicated more processing effort to minority than to majority messages. Conversely, participants whose moderate prior attitudes were not in strong conflict with the influence source s position processed the majority message more extensively than the minority message (Erb, Bohner et al., 2002). We were thus able to reconcile seemingly contradictory findings in the literature by Moscovici (1980) and Mackie (1987) by studying the effect of consensus in interaction with conflict. In a related study, Bohner, Dykema-Engblade, Tindale, and Meisenhelder (2006) showed that salient situational concerns with accuracy versus social comparison may determine whether majority or minority positions on a novel issue are processed more or less extensively. Participants for whom social comparison concerns had been primed processed minority
Social Influence and Persuasion 18 arguments more extensively than majority arguments a finding consistent with Moscovici s (1980) idea that social concerns decrease the processing of majority arguments. Participants for whom accuracy concerns had been primed were generally sensitive to the presented arguments, independent of variations in consensus a finding inconsistent with Moscovici s theory. Taken together, these findings encourage to search for other variables that interact with consensus in order to clarify contradictory theorizing and empirical findings in the literature. Mere consensus effects can also be used as a starting point to study minority influence. Following Moscovici, researchers have generally treated low consensus as a negative characteristic: What the minority does is bad because there are few who do it (Moscovici, 1980, p. 210). Accordingly, research efforts were devoted to identifying conditions that promote minority influence despite the drawback that the minority s position lacks high consensus. A full discussion of all pertinent models is beyond the present scope, but some examples may illustrate this concern with overcoming seemingly inevitable disadvantages inherent in minority status. According to CT itself, the key to minority influence lies in the consistent behavioral style and the positive attributions such behavior elicits; inconsistent minorities, on the other hand, would not be influential. In the framework of self-categorization theory (e.g., David & Turner, 2001; Turner, 1991), minority influence rests on the fact that minorities are (still) part of the in-group, thus taking advantage of the majority members' interest in maintaining group coherence and an overall positive group evaluation. In a similar vein, the leniency-contract model (Crano, 2001) holds that minority influence hinges on the leniency toward deviant in-group members. In Latané's social impact theory (Latané & Wolf, 1981; Nowak, Szamrej, & Latané, 1990), the minority can surmount the disadvantage of being small in number by the immediacy (e.g., physical closeness) and strength (e.g., social power) of their appeal. In sum, research was mainly concerned with the discovery of conditions where minorities are influential in spite of the fact that their position enjoys only little social support. Moreover, much of the minority influence
Social Influence and Persuasion 19 studied referred to the hidden impact of minorities (Maass & Clark, 1984), that is indirect influence on issues related to the focal issue of the influence attempt, rather than direct influence on the focal issue (for reviews, see Tanford & Penrod, 1984; Wood et al., 1994). By contrast, instead of asking under what conditions a minority may overcome the obstacle of being small in number, we take our consensus perspective as a starting point for examining conditions that make the low consensus attached to a minority itself appear attractive to influence targets. Under such conditions a minority is expected to exert greater influence than a majority, even on the focal issue of influence. What might such conditions be? There is a considerable amount of research suggesting that events, characteristics, and objects are evaluated more extremely the lower their perceived prevalence. For example, success will have more positive consequences, and failure more negative consequences, if consensus among actors is low, whereas consequences will be less extreme when consensus is high (e.g., Kelley, 1967). Research on the scarcity principle has shown that identical characteristics were evaluated more extremely the lower their perceived prevalence (e.g., Ditto & Jemmott, 1989). Research on commodity theory (e.g., Brock & Brannon, 1992) and self-categorization (e.g., Simon & Hamilton, 1994) also attest to the idea that evaluative judgments are more extreme when the object or characteristic is scarce. As minorities hold positions of low consensus, it is only a small step to assume that minority positions represent an object of evaluative extremity. If a certain position is correct, it appears more positive and appealing to share it with a minority, but less positive to share it with a majority. If a position is incorrect, however, it appears more negative and less appealing to share it with a minority of others, but not quite as negative to share it with a majority. We propose that this asymmetry in valence has an important consequence: Evaluative extremity renders the minority position a risk-inclined option in the sense that consequences are either very positive or very negative (i.e., one appears foolish if one is wrong, but brilliant if right). By
Social Influence and Persuasion 20 the same token, there is safety in numbers, as the old adage goes. It is safe to yield to majority influence, because any consequence is less extreme if shared with many others. It does not hurt much to be wrong if most others were wrong as well, but neither is it very rewarding to be right if that was true of most others as well. Accordingly, targets of influence will tend toward the minority position if they are inclined to make a risky decision. In our research (Erb, Bohner, Hilton, Krings, & Büscher, 2006), participants indeed judged an actor s decision to follow a minority (vs. a majority) as more rash, risk-loving, adventurous, risky, but less security-oriented and over-anxious. These results support the prediction that others judgments and decisions are perceived as more risky when representing an object of low consensus. But would participants themselves yield to minority influence under preference for risk, when their own decisions and attitudes were at stake? We explored this possibility in three studies. To induce preference for risky versus cautious judgments, we used a priming procedure introduced by Erb, Bioy, and Hilton (2002): Participants were asked to rank-order adjectives according to their frequency of use. In the riskseeking condition, the set of adjectives included primes with positive connotations for riskseeking (e.g., enterprising ) and with negative connotations for risk-avoidance (e.g., overanxious ). In the risk-avoidance condition, these were replaced by primes with negative connotations for risk-seeking (e.g., rash ) and positive connotations for risk-avoidance (e.g., conscientious ). After the priming, in an ostensibly unrelated second study, participants received a persuasive message that was said to come from either a minority or a majority of others. The basic finding was that recipients in the risk-seeking conditions were more influenced by the minority than by the majority, whereas recipients in the risk-avoiding conditions showed an opposite pattern. The effect was independent of whether the influence group represented an in-group or an out-group. However, the effect of priming on preference for the low or high consensus position
Social Influence and Persuasion 21 should disappear when concerns about accuracy are no longer relevant to the judgmental process assumed to be underlying the effect. Empirically, we found that the effect of priming disappeared when the influence group was portrayed to represent a minority or majority of experts on the topic under consideration. Obviously, inferences drawn from the assumption that experts are correct canceled out the effect of the risk priming. This result speaks to the idea that accuracy concerns are driving the observed effects. If an individual follows the minority, he or she will feel foolish his or her decision if the minority position turns out to be incorrect but will brilliant if this position turns out to be correct. To share a position with a majority of others would be safe, however, because there are many who are wrong or right. This research provides a unique example for a condition under which the minority position in itself appears more attractive to targets than does the majority position. Minority influence exceeded majority influence on the focal issue. Most recently, Imhoff and Erb (2006) started researching another factor that may render low consensus attractive to targets of influence, namely deindividuation. Deindividuation is a state in which an individual feels indistinguishable from other individuals (e.g., Zimbardo, 1969). Research suggests that individuals at times strive to avoid deindividuation (e.g., Snyder & Fromkin, 1980) and seek optimal distinctiveness (e.g., Brewer, 1991). Accordingly, a majority position would be less attractive than a minority position for recipients who feel deindividuated, because sharing a high consensus position would magnify the feeling of being a non-distinct member of a silent majority. On the other hand, a low consensus position represents something special, something of particular distinction, and thus allows one to regain their individual status. In a first study linking deindividuation and minority influence, Imhoff and Erb (2006) used the test feedback method (Snyder & Fromkin, 1980) to induce deindividuation. Specifically, participants received bogus personality feedback suggesting that their personality
Social Influence and Persuasion 22 was either average (deindividuation condition) or specific (control condition). Imhoff and Erb predicted that participants in the average condition would experience deindividuation. In an ostensibly unrelated second experiment, participants were exposed to a persuasive message on a topic promoted by either a minority or a majority of others. Attitude judgments in the deindividuation condition were indeed more favorable under minority influence than under majority influence, whereas an opposite pattern was found in the control condition. In a second study, deindividuated participants were given the opportunity to regain individuation by expressing personality characteristics that would make them unique as compared to other individuals. In this condition minority influence did not occur. Research on minority influence under risk preference and deindividuation goes beyond previous work on minority influence in that minority status is not regarded as a negative feature of the influence source to begin with. Other models of minority influence discuss conditions that foster minority influence despite the drawback that minorities represent positions of low consensus. If minority status is regarded as negative by default it makes little sense to inquire into conditions where minority status appears attractive to recipients. We found the notion that minority status inevitably denotes a negative feature suspect, chose a different approach, and asked whether there exist conditions that render the minority s low consensus appealing. And indeed, conditions exist that render minorities influential because they represent sources of low consensus. Such conditions increase the influence of low consensus sources on the focal issue (and not only on related issues) and, at the same time, reduce the influence of high consensus sources, thus interacting with consensus information. Guided by the fundamental insight that consensus is the only variable that necessarily covaries with minority and majority status, research within the mere consensus approach thus yielded three conclusions: (1) Consensus proved sufficient to produce effects on judgment formation and processing that in other models were less parsimoniously explained with
Social Influence and Persuasion 23 variables like social conflict, identification, dissent and so forth. (2) Beyond mere consensus effects, we found variables that interact with consensus in predictable ways (e.g., conflict with prior attitudes, risk-seeking, deindividuation). (3) Variables that produce mere main effects for both minorities and majorities (and presumably other influence sources as well) do not represent viable explanations for minority and majority influence for example, behavioral consistency (Moscovici, 1980), or tendencies to identify with the influence group (or any other source; e.g., David & Turner, 2001) likely promote the impact of any source (for further discussion, see Erb & Bohner, 2006). The distinction between normative and informational influence is thus irrelevant to the mere consensus approach. Recipients respond to consensus information, a variable to which the human mind may be specifically tuned (Erb & Bohner, 2001; Prislin & Wood, 2005), and other variables may interact with consensus in its effect on judgments, but there is no need to classify these variables in terms of whether they relate to the issue under consideration or some property of the influence group that would elicit tendencies towards identification. Instead, the mere consensus approach classifies variables in terms of whether they do or do not interact with consensus in their effects on processing and judgment formation in minority and majority influence contexts. PERSUASION So far, we have reviewed theories in the tradition of Asch s (1956) research on interpersonal and group-based influence. The social context in which such influence occurs was the main concern of this tradition, though more recent developments have incorporated assumptions introduced by models of persuasion into their theorizing. We now turn to the discussion of persuasion, and provide a review of dual-process models that have dominated persuasion research for a long time, as well as a recently developed single-process alternative. Dual-Process Models
Social Influence and Persuasion 24 Persuasion research since the mid-1980s has mainly been based on dual-process models: the elaboration likelihood model (ELM; Petty & Cacioppo, 1986a, 1986b; Petty & Wegener, 1999) and the heuristic-systematic model (HSM; Bohner et al.,1995; Chaiken, 1987; Chaiken et al., 1989; Chen & Chaiken, 1999). Both distinguish two qualitatively distinct modes of persuasion that form the endpoints of a continuum of processing effort. We will briefly outline their basic assumptions (see also Bohner & Wänke, 2002) and relate these assumptions to the distinction between informational and normative influence. The two modes of the ELM are called the central route, where persuasion is the result of targets' effortful scrutiny of message arguments and other issue-relevant information, and the peripheral route, where persuasion is mainly affected by peripheral cues (e.g., source likability, length of a message) through a variety of less effortful processing mechanisms (e.g., evaluative conditioning, mere exposure, heuristic processing). The HSM distinguishes between high-effort systematic processing, a mode largely identical to the central route, and low-effort heuristic processing, the specific application of highly accessible simple rules (e.g., "experts' statements are valid") in combination with salient and applicable cues in the persuasion setting (e.g., a communicator's academic degree). The ELM posits that "people are motivated to hold correct attitudes" (Petty & Cacioppo, 1986a, p. 6, emphasis ours). Similarly, accuracy motivation, meaning the objective of holding valid attitudes, features prominently in the HSM (e.g., Chaiken et al., 1989). This processing goal sets the stage for informational influence, and each of the two processing modes just outlined is seen as a viable means for obtaining this goal. As such, scrutiny of complex content arguments and reliance on a heuristic such as "high consensus implies correctness" would be seen as functionally equivalent. However, this is not the whole story. As the dual-processing models developed further, other processing objectives were explicitly included. Even in the earliest renditions of the ELM,