I recently finished reading Influence: The Psychology of Persuasion by Robert B. Cialdini. Cialdini, a professor of psychology at Arizona State University, provides a thorough analysis of the six “weapons of influence” that shape human behavior, backing his analysis with a multitude of interesting psychology experiments, real-life events, and other relevant evidence. These six “weapons of influence” are reciprocation, commitment and consistency, social proof, liking, authority, and scarcity.
Written in an understandable, witty, and sometimes humorous way, Influence appeals to the general public and demonstrates that one doesn’t have to be a professor or researcher to understand the fundamental principles of the psychology of persuasion. Cialdini does not use fancy language or academic jargon to give his book more authority. Instead, he writes in a conversational style, entertaining the reader every now and then with funny jokes and personal anecdotes. As a result, Cialdini manages to convey some of the most important insights and experiments from the field of psychology to ordinary people in an engaging way, making Influence one of the most popular psychology books of all time.
In the introduction, Cialdini points out that he does not include the principle of self-interest as a weapon of influence. He makes this omission not because he thinks self-interest is unimportant, but, on the contrary, because it is so obvious and self-evident that it would be unnecessary for him to discuss it. Instead, he focuses on the six weapons of influence I mentioned above that are less obvious and would be useful to describe and analyze.
Before delving into these six principles, Cialdini discusses how both humans and animals automatically respond to certain “triggers”. For example, the “cheep-cheep” sound that young turkey chicks make triggers the mothering behavior of female turkeys. It has been observed that if a turkey chick fails to make the “cheep-cheep” noise its “mother will ignore or sometimes kill it”. What is fascinating is that experiments with stuffed polecats (the natural enemy of the turkey) sounding the “cheep-cheep” noise via an inserted recorder can get a female turkey to embrace it and treat it like its own offspring. Turning off the recorder would result into a vicious attack from the turkey against the stuffed polecat, which resembles its natural enemy.
Cialdini employs many other examples of how animals automatically respond to certain “triggers”, from fireflies to fish. “It is almost as if the patterns were recorded on tapes within the animals”, the author writes, “Click and the appropriate tape is activated; whirr and out rolls the standard sequence of behaviors”. Before we conclude that this sort of click whirr behavior is confined to lower animals who don’t have the capacity of rational thinking that we humans do, there is ample evidence that humans exhibit the same kind of click whirr behavior, albeit to a lesser extent due to the higher human capability for conscious deliberation. The book revolves around six weapons of influence that triggers automatic responses from human beings, how they are employed, and how they can be resisted.
The first principle of influence is reciprocation. Humans generally repay favors with favors, and retaliate against threats and insults with threats and insults. The rule of reciprocation is pervasive throughout human culture, and a study done by sociologist Alvin Gouldner reported that “there is no human society that does not subscribe to the rule”. I personally believe that reciprocal behavior is engrained into the human psyche, and without it, it would be impossible for humans to cooperate.
Cialdini, nevertheless, dutifully provides numerous examples showcasing the power of reciprocation, from exchanges of foreign aid, the fund-raising strategy of the Hare Krishna Society, the prevalence of political favors in the realm of American politics, the marketing strategy of free sampling, the sparing of enemy soldiers in armed conflict, etc. Additionally, the author backs up his analysis with numerous psychology experiments.
Cialdini also discusses extensively the strategy of reciprocal concessions, demonstrating that people are more willing to compromise if the other party is willing to concede some of their own demands. Moreover, he shows that reciprocal concessions often produce positive feeling and greater commitment to the final deal from both parties.
It is best not to resist the rule of reciprocation, except when someone is clearly employing it to manipulate another for his own benefit without genuine sincerity. In that case the author recommends the reader not to reciprocate, saying, “The rule says that favors are to be met with favors; it does not require that tricks be met with favors”. Cialdini also says that people can simply refuse favors they do not want to repay.
The second principle of influence is commitment and consistency. This is the tendency that humans have for being consistent and sticking to what they committed to, which, in most cases, is a very good thing.
For example, Cialdini uses a psychology experiment of someone leaving a beach blanket five feet from a randomly chosen individual. When the experimenter leaves the blanket behind, another participant in the experiment would come and snatch the blanket away, and the researchers wanted to know how the individual nearby would react. When the blanket was left without a word spoken, only 20% of the subjects intervened to stop the theft. However, when the blanket was left after the experimenter asked the neighbor to “watch my things”, 95% of the subjects intervened to stop the theft. This large difference in intervention rates is due to the subject’s act of committing to watch the experimenter’s blanket and being consistent with that commitment.
There are numerous other experiments and examples that Cialdini uses to demonstrate the efficacy of commitment and consistency, the blanket experiment was simply the one I thought that best exemplified the principle.
The author also shows how people look at their own behaviors to determine their beliefs, values, and attitudes. This is why during the Korean War, the Chinese army incentivized American prisoners-of-war (POWs) to write pro-communist essays in exchange for prizes. After the end of the war, released American POWs from the Chinese prison camps were found to have substantially shifted war-related beliefs, with many expressing sympathy to the Chinese side of the story.
Cialdini also demonstrates how people are even more consistent with their decisions if their decisions are made in public, and how people are even more committed if their decision required an investment of great effort (which is the basis for the effectiveness of fraternity pledging traditions). As Cialdini puts it, “commitments are most effective in changing a person’s self-image and future behavior when they are active, public, and effortful”. Social scientists also showed that people are more likely to be committed to a decision if they made that decision “in the absence of strong outside pressures”.
The third principle of influence is social proof. People have the natural tendency to imitate the behavior of those around them, especially when in doubt or uncertain with what to do. Cialdini illustrates this phenomenon with the use of canned laughter in television. Even though viewers understand that the laughter is canned, studies have shown that canned laughter is effective in making scenes seem more funny to the audience.
The principle of social proof is often used by marketers to help increase sales, often by announcing how a product is the “fastest-growing” or “largest-selling”, with the understanding that the popularity of the product alone makes it more appealing to potential customers.
Social proof is so powerful, that it has been used to cure fear of dogs and social anxiety. To reduce fear of dogs in children, psychologists showed the children clips of similar-aged children playing with dogs, which led the formerly fearful children to begin playing with dogs afterwards. Likewise, psychologists helped children suffering from social anxiety by showing them multiple clips of a solitary child actively joining ongoing social activity, to everyone’s enjoyment. The result was impressive, as the formerly withdrawn children “immediately began to interact with their peers at a level equal to that of normal children in the schools”. An important point about social proof becomes apparent here: social proof works best when people are observing the behavior of similar others. Cialdini’s son, for example, only managed to overcome his fear of swimming when he saw his same-aged friend swim.
For more scientific proof, an experiment was done in Manhattan to explore this concept. Dropped wallets were placed around midtown Manhattan, all containing the same amount of money, with the contact details of the wallet’s “owner”, and a letter that looked like it was written by a previous person who found the wallet and intended to return it to the wallet’s original owner. Some of the letters were written in standard English to imply that the writer was American, while others were written in broken English to imply that the writer was a foreigner. The result was striking: “Only 33 percent of the wallets were returned when the first finder was seen as dissimilar, but fully 70 percent were returned when [the writer] was thought to be a similar other”.
Cialdini also provides fascinating real life examples illustrating the power of social proof, including a Chicago doomsday cult; the lack of bystander action during the murder of Catherine Genovese (this evidence has since been proven erroneous); the rise in suicides, automobile accidents, and plane crashes after a public suicide (publicized suicides statistically increase the number of suicides and suicides disguised as accidents eg. car or plane crashes), and the mass Jonestown suicides.
The evidence is clear that social proof is a powerful force, and that its influence is even stronger when people are uncertain or when people are observing the behavior of similar others. In order to resist the influence of social proof, Cialdini recommends that we be aware when misinformation is being used to take advantage of us (eg. canned laughter), and to not blindly follow the actions of others.
The fourth principle of influence is liking. It should go without saying that people are more likely to say yes to those they like. Cialdini uses the example of the Tupperware party, a party where the hostess makes a commission for every sale made during the party, which is mostly attended by her friends, who understand that they would be doing the hostess a favor by making purchases.
Cialdini also lists and describes the characteristics that contribute to the likability of a particular person, which are: physical attractiveness, similarity, compliments, contact and cooperation, and conditioning and association.
Physical attractiveness, similarity, and compliments should be fairly obvious.
Regarding contact and cooperation, we tend to be more receptive to people and things we are more familiar with, but not always. Although greater contact does increase liking when it occurs in a positive context, it can actually engender hostility or even hatred when it happens within a negative one. The ability for contact to increase liking is maximized when it occurs within the context of cooperation.
Cialdini demonstrates this concept with the boys’ summer camp experiment carried out by social scientist Muzafer Sherif, where the boys were separated into two groups, each with their own residence cabins. At first, activities were purposely competitive, and it did not take long for the two groups to be incredibly hostile to each other, with physical fights, exchanges of insults, cabin raiding, and other belligerent actions becoming commonplace. Even after introducing more pleasant activities for the two groups to do together, the boys continued to fight and insult each other. It wasn’t until the experimenters introduced cooperative activities, such as intentionally manipulating the camp truck to get stuck or shutting down the camp water supply and forcing the boys to work together to fix the problems, when the two groups of boys became friendlier with each other.
Additional examples, such as the racial integration of schools and the good cop bad cop routine, also illustrate the power of contact and cooperation to increase likability.
In regards to conditioning and association, people have the tendency to associate a person with whatever situation they encounter that person in. For example, in ancient times, the imperial messengers of Persia were responsible for bringing battlefield news back home. When the news was good, the messenger was treated to “food, drink, and women of his choice”. When the news was bad however, messengers were often executed, even though they had nothing to do with the battlefield failure. Likewise, weathermen often get hate-mail for announcing bad weather, but are treated a lot better when announcing good weather, even though they have nothing to do with causing the weather. Cialdini also points out that politicians always try to associate themselves with positive things that happened, even when they had nothing to do with them. All these examples, and many others, demonstrate how associating yourself with good things and avoiding association with bad things, even when you have nothing to do with them, increases likability.
The fifth principle of influence is authority. Most people have the tendency to obey authority, and if this was not true it would be very difficult to build complex societies governed by law and order.
Perhaps the most jarring example Cialdini uses to demonstrate the power of authority is the Milgram experiments. The psychology professor Milgram conducted a series of experiments where the subject of the study was told that he or she was participating in a study to examine how punishment affects memory. The subject meets the researcher, dressed in a formal white lab coat, and another subject, and they are told one subject would be responsible for learning pairs of words in a long list while the other subject would test the learner’s memory and deliver increasingly strong electric shocks for every mistake. Unbeknownst to the actual subject of the study, the “subject” assigned to the learner role is also an experimenter, and the electric shocks will not actually occur. However, the experimenter posing as the learner would be strapped to a chair and would scream and shout as the “electric shocks” get more powerful. Eventually the learner would ask the subject to stop, but the researcher would demand the subject to continue administering electric shocks. The objective of the study was to see if most subjects would obey the researcher or yield to the cries of mercy from the learner.
The results were unsettling: two third of the subjects “pulled every one of the thirty shock switches in front of them and continued to engage the last switch (450 volts) until the researcher ended the experiment”. Also, in the first set of experiments, not one of the forty subjects quit when the learner first demanded to be released. It wasn’t until 300 volts was reached that some of the subjects stopped, and they were a minority. The same experiment was repeated numerous times varying the demographics of the subjects (the first series of experiments consisted of only male subjects) and they all yielded similar results. Of all the examples and experiments Cialdini uses in the chapter on authority, the Milgram experiment was the most striking.
Cialdini also explains that there are several symbols of authority that can trigger compliance. They include titles (Dr., professor, etc.), clothes, and trappings (jewelry, expensive cars, etc.).
The sixth principle of influence is scarcity. Things seem more valuable if they are rarer and harder to get. To demonstrate, Cialdini opens the chapter discussing how he was enticed to visit a Mormon temple because it had just been renovated and its entirety was open to the public for a few days, after which the special inner section would be completely closed except for faithful members. Even potential converts would not have permission to enter. Because this might be the only chance Cialdini had to visit this special inner section, he had an urge to go, even though he had no interest in Mormonism nor in the architecture of Mormon temples. It became clear that Cialdini had the urge to go only because “If [he] did not experience the restricted sector shortly, [he] would never again have the chance”.
The scarcity principle affects human desire in a variety of instances. From limited time offers, rare antiques, collection of rare items, etc., scarcity plays a role in our decision making. At the heart of the scarcity principle is that “people seem to be more motivated by the thought of losing something than by the thought of gaining something of equal value”. Cialdini backs this claim with multiple examples and experiments.
People want what is difficult to get. One particular case of this phenomenon is known as the “Romeo and Juliet effect”, named after William Shakespeare’s Romeo and Juliet, a play about two lovers whose families feuded and hated each other. Despite the hostilities between their respective families, Romeo and Juliet loved each other with such intensity that the play culminated in their twin suicides. To demonstrate that the Romeo and Juliet effect is not just confined to fiction, a study done with 140 Colorado couples showed that couples suffering from parental interference reacted by “committing themselves more firmly to the partnership and falling more deeply in love”. In fact, “when the [parental] interference weakened, romantic feelings actually cooled”.
Similarly, when Dade County, Florida (containing Miami) banned laundry or cleaning products containing phosphates, demand for phosphate laundry or cleaning products shot up within Dade County. Miamians drove to nearby counties to load up on phosphate detergents and other phosphate products and hoarded them back home. Some “families were reported to boast of twenty-year supplies of phosphate cleaners”. Additionally, researchers found that Miami citizens “rated phosphate detergents as gentler, more effective in cold water, better whiteners and fresheners, more powerful on stains” than Tampa residents who were not affected by the ban.
When analyzing the optimal conditions for scarcity, Cialdini shows how newly experienced scarcity has a more powerful effect than constant scarcity. He describes an experiment where subjects were given chocolate-chip cookies. Some were given a jar containing only two cookies, others were given a jar of ten cookies, while others were first given a jar of ten cookies before it was taken away and replaced by a jar of two cookies. The experiment showed that those given the jar of two cookies rated the cookies more favorably than those given the jar of ten cookies. But those first given the jar of ten cookies but then saw the jar replaced by a jar of two cookies rated the cookies most favorably.
The idea that newly experienced scarcity is even more powerful plays a role in political revolutions. Social scientists have observed that the French, Russian, and Egyptian revolutions all occurred when “a time of increasing well-being preceded a tight cluster of reversals that burst into violence”.
Cialdini himself uses the Civil Rights movement as an example, and asks the reader why did it happen in the 1960s rather than in the 19th century or the early 20th century, when the oppression of blacks in the United States was far more egregious. Cialdini argues that it was because since World War II blacks experienced greater living standards and liberties, and when in the 1960s this progress faced backlash, blacks rose up and fought for full equality.
Cialdini’s last demonstration of the principle of scarcity covers the auctioning process, when prices are often bid up excessively. In fact, the American Broadcasting Company (ABC) once bid $3.3 million for a TV showing before soon realizing that they would lose $1 million for paying such a price. Afterwards ABC decided to “never again enter into an auction situation”.
I found Influence: The Psychology of Persuasion an eye-opening and very enjoyable read. The book explores insights that we intuitively understand, but have not consciously analyzed, to determine how we can better use or resist the principles of influence in our own lives. Written in a fun, conversational, and engaging way, Influence combines useful information with entertaining prose.
If you would like to read Influence: The Psychology of Persuasion yourself, here’s a link to order it on Amazon.
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