Most of the literature suggests a positive relationship between the number of influencing agents1and the strength of respective conformity effects (Asch, 1955; Insko, Smith, Alicke, Wade, & Taylor, 1985;
1Literature on the number of influencing agents in social influence processes often refers to the term “group size” (e.g.
Hewstone & Martin, 2012; Insko et al., 1985). As discussed in chapter 3.1, and as will be outlined at the end of this section, a group from a social psychology perspective has psychological implications for the target that exceed those of a plain accumulation of different individuals. Consequently, instead of group size, the term “number of influencing agents” will be used to connote this differentiation.
Lee & Nass, 2002). However, the exact properties of this relationship are still subject to debate, as empirical findings on this aspect are inconsistent, as will be outlined in the following.
Several theoretical approaches exist that aim to explain the relationship between the number of influencing agents and the strength of social influence in more detail. For example, social impact theory (Latané, 1981) focuses on fraction size as a central determinant of social influence. It is assumed that increasing fraction size enhances social influence in the form of a power function (rather than a linear relationship), in which every additional source of influence (influencing agent) exerts a smaller influence than the first one (Latané & Wolf, 1981; Bond, 2005).
Insko and colleagues (1985) provide several explanations for this power function. For example, they suggest that the target might perceive additional sources of social influence as having already been influenced by the first source as well. Another explanation refers to the target processing additional sources as part of a larger perception unit – both of which would explain why each additional source is less influential than the previous one (Insko et al., 1985). Looking at classical empirical studies, however, results are not always in line with this. For example, according to Campbell and Fairey (1989) as well as Insko et al. (1985), a lot of results obtained by Solomon Asch are not in line with the power function of social impact theory as he found additional confederates were more influential than the first one and conformity increased up to a number of four confederates, after which the effect remained constant. Asch (1955 in Bond, 2005) assumed that three influencing agents are necessary so that their opinion is not perceived as individualistic. If there are more than three influencing agents, the target merely perceives this as repeated confirmation (Asch, 1955).
To summarize, the exact relationship between the number of influencing agents and the strength of social influence is yet to be determined (although all results agree that it is a positive relationship).
Empirical results further suggest that it might be affected by several aspects, such as context or the salient goal for yielding to social influence: Regarding the target’s goal for yielding to social influence, the effect of the number of influencing agents on conformity can be explained via the goal of accuracy as well as that of affiliation (as suggested by Insko et al., 1985). The more people agree on a subject, the more likely it is that this consensus is believed to reflect actual reality, because it is likely to be based on an external context. Hence, a larger number of influencing agents is assumed to be a more reliable indicator of accuracy. When the goal of affiliation is salient, a larger number of influencing agents might possess a stronger potential for rewards and punishments (Insko et al., 1985). Depending on the underlying goal, the number of influencing agents may affect social influence differently (Bond, 2005). For example, Campbell and Farey (1989) conducted a study following a Crutchfield-paradigm (non-FTF-situation with false feedback on others’ evaluations in a
task). They found that social influence based on the goal of accuracy follows a power function (as suggested by social impact theory), while the goal of affiliation fosters an s-shaped curve, suggesting that at some point the effect of additional sources remains constant. When the evaluation of the influencing agents was thought to be accurate, the effect of group size was small and there was basically no difference between public and private evaluation (Campbell & Farey, 1989). The authors assumed that for pursuing the goal of accuracy, the first source of influence is crucial and that each additional source produces redundancies (as also suggested by Insko et al. (1985) when explaining the power function). When the evaluation of the influencing agents was obviously wrong (eliminating effects based on the goal of accuracy, an assumption the authors based on Asch, 1952), the effect of group size was very strong and there was a clear difference between public and private evaluation (Campbell & Farey, 1989). Based on this study, Bond (2005) further investigated whether the relationship between the number of influencing agents and the strength of conformity varies, depending on whether the evaluation is made publicly or privately and whether the situation follows an Asch- (suggesting influence based on the goal of affiliation, see chapter 3.3.2.2) or a Crutchfield-paradigm (suggesting influence based on the goal of accuracy). Bond (2005) presents a meta-analysis of 125 empirical studies that use a line judgment task (as used by Asch, e.g. 1955), in which participants were confronted with the wrong assessment of others (one or several individuals).
Regarding public conformity, results of the meta-analysis showed rather small correlations between the number of influencing agents and the target’s response, both for the Asch-paradigm and for the Crutchfield-paradigm (the latter showing the smallest correlation). For the Asch-paradigm, the effect remained constant after the third additional source. In contrast to this, when it came to private conformity, studies that employed the Asch-paradigm revealed a negative relationship between the number of influencing agents and conformity, while the Crutchfield-paradigm led to a strong positive correlation. The author suggested that the negative relationship in the Asch-paradigm is a sign of participants feeling the need to preserve their individuality after conforming publicly (Bond, 2005).
Further studies examining the relationship between fraction size effects and goals for yielding to social influence manipulated participants’ prior experience (Rosenberg, 1961, see also chapter 3.3.3.3) as well as the publicness of evaluation (Insko et al., 1985) and the ambiguity of the situation (Insko et al., 1985) to deduce respective goals. For example, Rosenberg (1961) found that a prior experience treatment that persuaded participants they were unsuccessful at solving the task increased conformity (in a curvilinear relationship), suggesting they pursued the goal of accuracy. Insko et al. (1985) found evidence that effects based on both the goal of accuracy and the goal of affiliation were affected by fraction size in the same way: four confederates were more influential than one confederate.
Besides group size/number of influencing agents affecting the strength of social influence by serving as an indicator of what is accurate or by increasing social pressure, the role of group and interpersonal processes needs to be considered. It has been discussed in earlier chapters (e.g. 3.1) that both single individuals and groups (or single individuals who represent a group) can elicit conformity.
By definition, a group is more than the sum of several individuals, but a group implies having psychological consequences for the target (Kiesler & Kielser, 1970). As a consequence, there might be different mechanisms coming into play depending on what the influencing agent represents, for example when contrasting Kelman’s (1958; 1961) concept of identification and self-categorization theory from the social identity framework (chapter 3.3.2.3): Depending on whether the influencing agent is (or is perceived as being) a group or an individual, social influence might be affected by different aspects, e.g. interpersonal relationships or group cohesiveness (Sassenberg, 2011). This aspect is presumably connected to the goal of positive self-evaluation. Based on this, it can be assumed that the number of influencing agents might also determine whether the target is subject to group or interpersonal processes and associated mechanisms. For example, one good friend might be more persuasive than three unknown people, as shown by Egebark & Ekström (2011, see chapter 3.2.1) – or in other words: The effects of group size/number of influencing agents might interact with other influential factors, such as relationship towards the source, depending on which goal of the target is salient.