Social Impact Theory was created by Bibb Latané in 1981 and uses three principles to describe how individuals can be "sources or targets of social influence". The three principles which determine how social forces create social impact are the strength of the source of impact, the immediacy of the event, and the number of sources exerting the impact.Michael A. Hogg, Scott Tindale; Blackwell Handbook of Social Psychology: Group Processes; John Wiley & Sons (2008); p.239; , The more targets there are to impact, the less impact each target receives. Social impact theory has been applied to a variety of concepts in psychology including diffusion of responsibility, social loafing, stage fright, and persuasive communication.
Original research According to psychologist Bibb Latané, social impact is defined as any influence on individual feelings, thoughts, or behaviors that is created from the real, implied, or imagined presence or actions of others. In the original 1981 paper, Latané developed the social impact theory using three key variables: Strength (S) is the importance of a person to the individual being influenced. It covers stable, trans-situational, intrapersonal factors - size, intellect, wealth - together with dynamic, situation-specific relational components, such as belonging to the same group. Immediacy (I) considers how recently the event occurred and whether or not there were other intervening factors. The number of sources (N) refers to the number of sources of influence. Based on these variables, Latané coined three mathematical principles to describe social impact: social forces, the psychosocial law, and the multiplication/division of impact.
Psychosocial law The psychosocial law posits that the impact of any individual sources of social influence decreases as the total number of sources increases. Going from one to two sources will increase the amount of social influence more than going from 99 sources to 100. most significant social impact on an individual will occur from 0 sources to 1 source. The equation Latané uses for this law is . That is, the impact of social influence (I) is determined by the number of sources of social influence (N) raised to some power (t) and multiplied by a scaling constant (s). Latané verified this relationship by applying to previous studies on conformity and embarrassment.
Latané found mixed support applying this relation to research on conformity.Solomon Asch's famous conformity experiments among college students challenged this psychosocial law by demonstrating that the amount of social impact was not impacted by the number of sources after a certain point. In contrast, a subsequent study by Gerard, Wilhelmy, and Conolley examined conformity in high school students, who were considered more susceptible to social impact than college students. This study supported the psychosocial law, finding that the strength of social impact increased with the number of sources inline with the proposed equation.
Latané further applied the psychosocial law to imitation, referencing an experiment in part conducted by Stanley Milgram in which varying numbers of confederates stood on a New York City street corner looking up at window on a nearby building. The results indicated that an increased number of confederates led to more passersby imitating the behavior, with the amount of increase reducing as additional confederates were added. Similarly, in a study on stage fright and embarrassment conducted by Latané and Harkins, the findings aligned with the psychosocial law, showing that an increase in audience size correlated with heightened anxiety, with the main impact occurring between no audience and a single audience member.
Multiplication/divisions of impact Latané's multiplication/divisions of impact states that the strength, immediacy, and number of targets of social influence has an inverse relation with social impact as the strength, immediacy, and number of source of social influence. As the strength, immediacy, and number of targets of social influence increase in a social situation, the impact of the social influence decreases. The equation that represents this division is . ` This law comes from Latané's work on diffusion of responsibility, in which individuals feel less accountable as the number of people present increases. Latané argues that this law is in line with the Bystander effect in which, emergency situations, the impact of the emergency is reduced when more people are present. Latané argued that his model fit a variety of studies on the diffusion of responsibility.
Strengths and Weaknesses The social impact theory is both generalizable and specific. It is general because it uses one set of equations, which apply to many social situations. For example, the psychosocial law can predict conformity, imitation, and embarrassment. Yet, it is also specific because the predictions that it makes are specific and can be applied to and observed in the world. The theory is falsifiable in that it predicts specific, mathematically described predictions which can be tested. The original research found that social impact theory is able to fit a variety of preexisting results which adds to validity.
While social impact theory explores social situations and can help predict their outcomes, it also has some shortcomings and unresolved questions. The rules guiding the theory depict people as recipients who passively accept social impact and do not take into account the social impact that people may actively seek. The model is also static and does not fully compensate for the dynamics involved in social interactions. The theory fails to address some pertinent issues. These issues include finding more accurate ways to measure social outcomes, understanding the "t" exponent in psychosocial law, taking susceptibility into account, understanding how short-term consequences can develop into chronic consequences, applying to group interactions, and understanding the model's nature (descriptive vs. explanatory, generalization of results vs. theory).
Applying social impact theory The social impact theory specifies the effects of social variables - strength, immediacy, and number of sources - but does not explain the nature of these influencing processes. Various factors are not considered by experimenters while implementing the theory. Concepts such as peripheral persuasion affect how communicators may be more credible to some individuals and untrustworthy to others. The variables are inconsistent from individual to individual, possibly associating strength with source credibility and attractiveness or immediacy with physical closeness. Therefore, in the social impact theory's application, the idea of persuasiveness, the ability to induce someone with an opposing position to change and supportiveness, the ability to help those who agree with someone's point of view to resist the influence of others, is introduced. Ultimately, an individual's likelihood of change and being influenced is a direct function of strength (persuasiveness), immediacy, and the number of advocates, and is a direct inverse function of strength (supportiveness), immediacy, and number of target individuals.
Subsequent development The dynamic social impact theory, as proposed by Bibb Latané and his colleagues, describes the influence of members between majority and minority groups. The theory serves as an extension of the originating social impact theory (i.e., influence is determined by the strength, immediacy, and number of sources present) as it explains how groups, as complex systems, change and develop over time. Groups are constantly organizing and re-organizing into four basic patterns: consolidation, clustering, correlation, and continuing diversity. These patterns are consistent with groups that are spatially distributed and interact repeatedly over time.Forsyth, D.R. (2009). Group dynamics: New York: Wadsworth. [Chapter 7]
1. Consolidation - as individuals interact with each other regularly, their actions, attitudes, and opinions become more uniform. The opinions held by the majority tend to spread throughout the group, while the minority decreases in size.
E.g., Individuals who live in the same college dormitory will, over time, develop similar attitudes on various topics.
2. Clustering - occurs when group members communicate more frequently due to proximity. As the law of social impact suggests, individuals are susceptible to influence by their closest members, and so clusters of group members with similar opinions emerge in groups. Minority group members are often shielded from majority influence due to clustering. Therefore, subgroups can emerge that may possess similar ideas to one another but hold different beliefs than the majority population.
E.g., Neighbours on a suburban street convince other neighbors to form a community-watch group.
3. Correlation - over time, individual group members' opinions on various issues (including issues that have never been openly discussed before) converge so that their views become correlated.
E.g., Individuals in an executive society (i.e., Board of Directors) may agree on topics they have discussed throughout a conference - such as the best financial plan- but they also agree on topics they have never discussed: the best restaurant to eat in the city.
4. Continuing diversity - as mentioned previously, minority members are often shielded from majority influence due to clustering. Diversity exists if the minority group can resist the majority's influence and communicate with majority members. However, if the majority is large or minority members are physically isolated from one another, this diversity decreases.
E.g., A jury of 10 members convenes in a boardroom to provide a final verdict (which must be unanimous). Two jury members disagree with the majority and delay the final decision (continues diversity).
Contemporary research In 1985, Mullen conducted a meta-analysis on the validity of two factors that Latané associated with social impact theory: source strength and immediacy. The studies that were analyzed were sorted by the method of measurement used, with the self-reported data in one category and the behavior measurements in the other category. Mullen's results showed that the source strength and immediacy were only supported in cases in which tension was self-reported and not when behavior was measured. He thus concluded that Latané's source strength and immediacy were weak and lacked consistency. Critics of Mullen's study, however, argue that perhaps not enough studies were available or included, which may have skewed his results and given him an inaccurate conclusion.