Social Influence

Every species of social animal and eusocial insect must have a means of social influence—a way for one or more members of the species to direct, coordinate, and influence other members of the species. Such social influence tactics determine the allocation of resources within a community of the species and also provide an evolutionary advantage to social species in their quest to gain the resources needed for survival. For example, Pogonomyrmex barbatus (red harvester ants) dynamically allocate tasks within their colonies (e.g., forging, patrolling, midden work) by having each ant follow a social consensus rule of “the more contact with another ant succeeding at a task, the more likely I should switch to that task.” Pan troglodytes (chimpanzees) use a number of social influence tactics to establish social relationships and to allocate resources, including coalition formation, reciprocity, submissive greetings to establish a dependency relationship, empathy, and the establishment of norms. Humans (Homo sapiens) employ a variety of social influence techniques that are highly adaptive to a range of social and environmental situations.

Social Influence Definition

Social InfluenceSocial influence means any noncoercive technique, device, procedure, or manipulation that relies on the social psychological nature of the organism as the means for creating or changing the belief or behavior of a target, regardless of whether or not this attempt is based on the specific actions of an influence agent or the result of the self-organizing nature of social systems. It can be contrasted with two other forms of influence: (1) power or the control of critical resources, including its most extreme application of war; and (2) outright deception to lead an organism to believe he or she is doing X but in reality is doing something else. In other words, social influence uses tactics that appeal to the social nature of the organism. Among humans, it is their nature to fear, feel dissonance, return a favor, value what is scarce, empathize with others, make judgments dependent on context, seek phantom goals, and easily adopt the social roles of their social group, along with other characteristics. Social influence tactics make use of these attributes of human nature to invoke such processes as conformity (creating or changing behavior or belief to match the response of others), persuasion or attitude change (change in response to a message, discourse, or communication), compliance (change in response to an explicit request), yielding to social forces (change in response to the structure of the social situation), or helping (change in response to someone’s need).

History of Social Influence Research

Throughout human history as a species, human beings have attempted to understand what influences and persuades them. Some of these attempts were based on superstitions and pseudoscientific beliefs and thus have missed the mark. For example, at various times in human history, people have believed that the stars and the planets (astrology), bumps on our head (phrenology), the four humors (or special fluids of blood, yellow bile, black bile, and phlegm), magnetic forces (Mesmerism), and witches, demons, and angels have mysteriously controlled human behavior.

Nevertheless, some members attempted to use empirical observation to understand persuasion and influence. The first recorded attempt to classify social influence tactics was conducted by the Sophists (including Protagoras, Isocrates, and Gorgias) of 5th century B.C.E. Greece. (In China in the 3rd century B.C.E., Han Fei Tzu developed a handbook with a similar goal.) The Sophists were itinerate teachers of persuasion and created handbooks of “commonplaces”—general arguments and techniques that could be adapted for a variety of persuasive purposes. Sometime around 333 B.C.E., Aristotle began compiling a list of these influence techniques (mostly taken from the

Sophists) in his book Rhetoric, the earliest surviving book on influence. The next great attempt to codify the ways of influence occurred in Rome with the efforts of the lawyer Cicero and the rhetoric instructor Quintilian.

However, it was not until the late 19th century that the scientific method was used to explore the ways of social influence. In 1898 Norman Triplett conducted the first social influence experiment by having people turn fishing cranks either alone or in the presence of others. He found evidence for social facilitation or faster cranking turning when others were present. Also in the late 19th century, Gustave Le Bon popularized a theory of crowd behavior based on the metaphor of hypnosis or the notion that the crowd took over the will of the person much like the suggestions of a hypnotizer commands the unconscious of the hypnotized. Although popular in his day, Le Bon’s theory has not stood the test of time, but it did serve as a foil to stimulate later research.

World War I changed the trajectory of social influence research. In the United States and Britain, the war was marked by a period of patriotism; after the war, many citizens became disillusioned by the results and came to feel that they had been duped by propaganda. The zeitgeist of the times championed the belief that social influence and mass propaganda were all-powerful (based on either suggestion theories from psychoanalysis or behaviorism’s belief in malleable human behavior). Researchers and scholars began documenting this belief as well as attempting to find ways to inoculate citizens from propaganda. Social influence research during the interwar period featured the use of the experimental method to document that “persuasion happens,” case studies of propaganda, and the development of survey methods. In the 1930s, a group of scholars formed the Institute for Propaganda Analysis with the expressed goal of teaching Americans about how to counter propaganda.

As with World War I, World War II also changed the trajectory of social influence research. As part of the war effort, many scholars became deeply involved in social influence research, including campaigns to maintain and promote the morale of the public and troops and to counter Nazi propaganda. After the war, these researchers returned to their universities and began (along with their students) to study social influence phenomena that had been at the heart of the war effort, such as conformity, mass communications, prejudice, power, and obedience to authority. The result was a flourishing of exciting scientific research on social influence and the development of a large body of knowledge about how influence works and why. To give a flavor for research on social influence during the 1950s and 1960s, this section briefly describes three lines of research.

At Yale University, Carl Hovland conducted a program of experimental research investigating the effects of various variables (e.g., source credibility, individual differences, organization of the message) on persuasion. The results, in contrast to assumptions made during the interwar years, showed weak effects of these variables on social influence. Similar minimum effects were being obtained in survey research, which found, for example, that few voters changed their voting preferences as a result of mass media content. The resulting model of influence was termed minimum effects and posited that persuasion was the result of a series of steps (attention to the message, comprehension, learning of message, yielding, and behavior), each with a decreasing probability of occurring.

In 1968 to account for empirical anomalies in the Hovland model, Anthony Greenwald presented a revision, which replaced the intervening steps with one core process: cognitive response. The resulting approach to persuasion, known as the Ohio State School, states that influence is the result of the thoughts running through a person’s head as he or she processes a persuasive communication. (In this case, the power of the mass media is dependent on its ability to change cognitive responses, which can vary as a result of a number of factors.) Subsequent research has focused on the question, “What determines a person’s cognitive response to the message?” with one of the most comprehensive answers provided by the elaboration likelihood model of Richard Petty and John Cacioppo.

A second line of research stems from Leon Festinger’s 1957 book, titled A Theory of Cognitive Dissonance. In this book, Festinger puts forth a deceptively simple thesis: When a person is confronted with two conflicting thoughts, it creates a tension state; that individual is highly motivated to reduce that tension or dissonance. This simple theory stimulated a wealth of interesting research hypotheses and experiments about the nature of social influence. The research on dissonance has been very useful for identifying and understanding a range of social influence tactics, such as effort justification, insufficient justification, commitment, and guilt, and has provided researchers a means of understanding seemingly counterintuitive instances of influence.

The final line of research obtained what is perhaps the single most important discovery in social influence research and most likely within the discipline of psychology itself—that situations are more powerful in controlling human behavior than most people think. This line of research began by questioning research results presented in a dissertation in 1935 by Muzafer Sherif. In that research, groups of people judged the movement of the autokinetic effect (an illusion that a light moves when placed against a dark background). Sherif’s results showed that groups quickly developed norms for making these judgments and that these norms would guide their subsequent judgments. In the late 1940s, Solomon Asch looked at the conformity results obtained by Sherif to conclude that the findings were dependent on the nature of the ambiguous autokinetic stimuli used in the research; Asch further reasoned that surely conformity would not occur if a group of people made obviously incorrect judgments of an unambiguous stimulus. In the true spirit of science, Asch promptly designed a set of experiments to prove himself wrong. In his studies, Asch had a group of confederates judge the length of lines and clearly provide a wrong answer. Surprisingly, he found that a majority of subjects went along with the group.

In the early 1960s, Stanley Milgram was interested in explaining obedience to authority in terms of personality and culture-based character traits (e.g., “Germans are most obedient” as an explanation for the Holocaust). He also believed that Asch’s line judgment task had no personal consequences for the subjects and thus was not a full test of conformity. Milgram designed his famed “obedience to authority” procedures to take account of these hypotheses. The results showed that a majority of people were willing to give another person painful shocks when commanded to do so by an authority and that character and personality did not explain these results. Instead, Milgram’s research was a powerful demonstration of the power of the social situation to control behavior—a finding that has been repeatedly demonstrated in studies such as Bibb Latane and John Darley’s bystander apathy research and Philip Zimbardo’s Stanford prison experiment.

The modern era of social influence research began with the 1984 (last revised in 2001) publication by Robert Cialdini of his book Influence. This seminal work summarized past social influence research, categorizing it into six core principles of influence: reciprocity, scarcity, consistency, authority, liking, and social proof. More importantly, it serves as an inspiration for a new generation of social influence researchers. In no uncertain terms, Cialdini showed that complex influence processes can be understood in terms of basic principles and that these principles can be powerful in understanding and changing the social world. In his empirical work, Cialdini has shown that seemingly intractable social influence processes can be untangled and made sense of through the careful application of the experimental method, thereby inspiring the next generation of researchers to do the same.

Social Influence Analysis

To understand a eusocial or social species and to predict the behavior of its members, it is essential to analyze the nature of social influence within that species. Such a social influence analysis consists of a description of the social influence tactics used by species members, principles or psychological processes underlying those tactics (e.g., dissonance, social cognition principles), how influence is exchanged within a community (e.g., likely tactics employed, profiling of influence agents), patterning of influence within a species and its communities (e.g., communication networks, channels of influence, social institutions), and theories and models of the operation of influence.


  1. Cialdini, R. B. (2001). Influence (4th ed.). Boston: Allyn & Bacon.
  2. Pfeffer, J., & Salancik, G. R. (1978). The external control of organizations. New York: Harper & Row.
  3. Pratkanis, A. R. (2006). Why would anyone do or believe such a thing? A social influence analysis. In R. J. Sternberg, H. Roediger III, & D. Halpern (Eds.), Critical thinking in psychology (pp. 232-250). Cambridge, UK: Cambridge University Press.
  4. Pratkanis, A. R. (Ed.). (2007). The science of social influence: Advances and future progress. Philadelphia: Psychology Press.
  5. Pratkanis, A. R. (2007). Social influence analysis: An index of tactics. In A. R. Pratkanis (Ed.), The science of social influence: Advances and future progress (pp. 17-82). Philadelphia: Psychology Press.
  6. Pratkanis, A. R., & Aronson, E. (2001). Age of propaganda: The everyday use and abuse of persuasion. New York: W. H. Freeman.
  7. Pratkanis, A. R., & Shadel, D. (2005). Weapons of fraud: A source book for fraud fighters. Seattle: AARP Washington.