Influence by Robert B. Cialdini: Summary and Notes

"To deal with it, we need shortcuts."

Chapter 2Reciprocation: The Old Give and Take... and Take

A professor who sent Christmas cards to strangers received a flood of cards back. The rule for reciprocation says we should repay in kind what another person has provided, and Cialdini reports that sociologists know of no human society without it; anthropologists treat the web of indebtedness as what allowed division of labor and trade. In 1985 the Ethiopian Red Cross, in the middle of famine, sent $5,000 to Mexico City earthquake victims because Mexico had helped Ethiopia in 1935.

In Dennis Regan's study, an assistant named Joe who brought an unsolicited Coke to a subject later sold that subject twice as many 25-cent raffle tickets, and the gift wiped out the usual link between liking Joe and buying from him. The Hare Krishnas turned public dislike into donations by pressing a flower or a book on travelers first and refusing to take it back; Cialdini once followed a member who retrieved discarded flowers from airport trash cans to give out again. Free samples work the same way: Amway's "bug" of products left for 24, 48 or 72 hours led customers to buy about half of it. Uninvited favors still create debt, as when address labels nearly doubled a disabled veterans group's response from about 18% to 35%. A small favor can also buy a large one, as with the student who lent her new car to a near stranger who had once jump-started it, and who totaled it. Jonestown survivor Diane Louie said she had refused Jim Jones's special favors because once he gave her privileges, he would have her.

The rule also covers concessions. A Boy Scout who asked Cialdini to buy $5 circus tickets, then retreated to $1 chocolate bars, sold him two. Cialdini's team asked students to chaperone delinquents on a zoo trip; 83% refused, but after first refusing a two-year counseling commitment, three times as many agreed, from 17% to 50%. This rejection-then-retreat technique also engages contrast, and its targets more often follow through and feel responsible and satisfied. He reads the Watergate break-in this way: G. Gordon Liddy's $250,000 plan was approved after $1 million and $500,000 versions were rejected, and the one official who opposed it, Frederick LaRue, had missed the earlier meetings. The defense is to accept genuine favors and concessions but to redefine tricks as tricks.

Cialdini traces the rule into politics and selling. Lyndon Johnson passed so much legislation because of the favors he had banked over years in Congress, while Jimmy Carter, who campaigned as indebted to no one in Washington, found no one there indebted to him. Charles Keating, asked whether his $1.3 million in contributions to five senators had bought their help, said he certainly hoped so. An Indiana grocer sold 1,000 pounds of cheese in a few hours by letting customers cut their own free samples. Television producer Garry Marshall used the retreat on network censors, putting the word "virgin" into a Happy Days script seven times so they would cut six and keep one. A Brunswick dealer who showed customers a $3,000 billiard table first, then moved down the line, raised the average sale from $550 to over $1,000. A reader who sold service contracts pitched the three-year plan at about $140 before retreating to the one-year plan at $34.95, and sold contracts to 70% of his customers while colleagues stayed near 40%.

Cialdini's worked example of the defense is a free home fire inspection that turns into a pitch for an expensive alarm system. Once the extinguisher and inspection are recognized as sales devices, he writes, there is no debt to repay, and the reciprocity rule even entitles you to take the gifts and show the inspector the door.

"The rule says that favors are to be met with favors. It does not require that tricks be met with favors."

Chapter 3Commitment and Consistency: Hobgoblins of the Mind

Bettors at a racetrack grow more confident in their horse right after placing the bet. Cialdini's neighbor Sarah canceled her wedding to take back her old boyfriend Tim, who promised to marry her and stop drinking, then did neither; two years later she was more devoted to him than ever. On a New York beach, only 4 of 20 bystanders challenged a staged radio thief, but 19 of 20 did after agreeing to "watch my things." Consistency is usually valued and adaptive, and automatic consistency saves us the labor of thinking, and sometimes from conclusions we would rather avoid, as with the people who paid their $75 down payment for Transcendental Meditation right after a logician demolished the pitch, so they would not go home and think about it.

Commitment is the trigger. Toy companies advertise toys before Christmas, undersupply them so parents buy substitutes, then advertise again in January to parents bound by their promise. In Steven J. Sherman's study, asking people to predict whether they would volunteer for the American Cancer Society raised volunteering by 700%. Asking "How are you feeling this evening?" before a charity request nearly doubled agreement, 32% against 18%. The Chinese in Korean War prison camps started with small statements, had prisoners write them down, read them aloud and enter essay contests with small prizes, building toward collaboration. Freedman and Fraser found 76% of homeowners agreed to a huge "Drive Carefully" billboard after first displaying a 3-inch sign, and about half did after signing an unrelated petition, because the small act changed how they saw themselves.

Commitments change self-image most when they are active, public and effortful, which is why written goals, customer-completed sales forms and testimonial contests work, and why initiation rites from the Thonga to fraternity hell weeks resist reform: Aronson and Mills showed that people value a group more the harder it was to join. Most important, people must feel inner responsibility. In Freedman's study, boys warned under severe threat not to play with a robot did so later at a 77% rate, against 33% for boys given only a mild instruction. Commitments then grow their own legs, which is how car dealers' lowball works: an attractive price wins the decision, then a $400 "error" removes it. Iowa homeowners promised newspaper publicity for saving energy saved even more after the promise was withdrawn. The defenses are a tight stomach when trapped into a request you don't want and, for subtler cases, the heart of hearts question: knowing what I now know, would I make the same choice again?

Public commitments are the most lasting. In Deutsch and Gerard's study, students who wrote down and signed their estimates of line lengths clung to them hardest when shown they were wrong; even those who wrote on an erasable pad resisted more than those who kept the estimate in their heads. Juries voting by show of hands hang more often than juries using secret ballots. Weight-loss clinics have clients show their goals to friends, and a San Diego woman quit smoking by handing signed cards promising never to smoke again to everyone whose respect she wanted. Cialdini himself was once trapped by a survey taker whose questions got him to brag about his social life, then offered him a club membership that would save someone so active up to $1,200 a year. In a reader's report, a woman in Portland who kissed a stranger to help him win a "contest" ended up buying a magazine subscription from him.

"It is quite simply our nearly obsessive desire to be and to appear consistent with what we've already done."

A note on editions: the print link sells the Revised Edition that these notes follow. The Kindle and audiobook links go to Influence, New and Expanded, a later edition, and the audiobook there is read by Cialdini.

Chapter 4Social Proof: Truths Are Us

Everyone Cialdini asked hated canned laughter, yet it makes audiences laugh longer and rate jokes funnier, especially poor ones. The principle of social proof says we decide what is correct by finding out what other people think is correct, which usually works. Bartenders salt tip jars, Billy Graham's organization prepared 6,000 people to come forward on cue, and Albert Bandura cured children's fear of dogs by having them watch another child play with one; after four days, 67% would climb into a playpen with a dog. Robert O'Connor's 23-minute film turned withdrawn preschoolers into their schools' most social children.

Social proof works best under two conditions. The first is uncertainty. A Chicago doomsday group studied by Festinger, Riecken and Schachter shunned publicity until the flood and the rescuing spaceship failed to arrive, then began phoning newspapers and recruiting, because physical proof had failed and only social proof was left. Uncertainty also explains the 38 witnesses who did nothing during Catherine Genovese's murder in 1964. Latané and Darley showed that a seizure victim got help 85% of the time from a lone bystander and 31% of the time with five present, because responsibility is diffused and each person reads the others' calm as a sign that nothing is wrong. Cialdini's advice to a victim is to pick one person, point, and give a specific instruction; he did exactly that after a car accident and got immediate help.

The second condition is similarity. Lost wallets carrying a letter from a previous finder were returned 70% of the time when he seemed similar and 33% when he seemed foreign. Cialdini's three-year-old son learned to swim because another three-year-old could. David Phillips found that front-page suicide stories are followed by an average of 58 extra suicides and by spikes in fatal car and plane crashes, with victims resembling the person in the story. Cialdini reads Jonestown, where 910 people died, the same way: in an alien jungle, the only similar others were fellow members. His defense is to watch for faked social evidence, such as staged testimonials, and for crowds simply copying each other, like the buffalo driven over cliffs.

The bystander research has a hopeful side. When people are sure an emergency exists, they help: in Florida experiments a visibly hurt maintenance man was helped 100% of the time in two studies and 90% of the time even when helping meant touching dangerous wires. The trouble comes in ambiguous situations among strangers, and Cialdini points out that cities are noisier, more crowded and full of strangers, which explains bystander inaction without any theory of a cold society. In a Toronto study, lone bystanders helped 90% of the time but only 16% of the time beside two passive bystanders; smoke seeping under a door was reported by 75% of people alone, 38% of three-person groups, and 10% of groups that included two coached to ignore it.

Phillips also found that televised heavyweight championship fights were followed by rises in homicides whose victims resembled the losing fighter. Faked social proof is old: in 1820 two Parisians began leasing out claques, paid applauders for opera, complete with specialists who wept or called for encores and published rate cards. A highway patrolman in Cialdini's class described rush-hour crashes caused when a couple of cars changed lanes by coincidence and dozens behind them followed, assuming an obstruction that was never there. In a reader's report, a racetrack employee explained how a bettor can make a long shot the early favorite with a quick $100 bet, wait for the crowd to follow, then bet heavily on the horse he really likes.

"Usually, when a lot of people are doing something, it is the right thing to do."

Chapter 5Liking: The Friendly Thief

At a Tupperware party the real request comes from the hostess, a friend, and Cialdini reports that the social bond is twice as likely to determine purchase as preference for the product; sales were estimated at over $2.5 million a day. Shaklee's "endless chain" sends salespeople to each new prospect with a friend's name. Joe Girard, called the world's greatest car salesman, sold more than five cars a day by offering a fair price and someone people liked, and mailed his more than 13,000 customers a card every month that said "I like you."

The factors that produce liking are physical attractiveness, whose halo won attractive Canadian candidates more than two and a half times as many votes while 73% of voters denied any influence; similarity, which car salesmen manufacture from what they find in a trade-in; compliments, which work even when untrue; and contact and cooperation. Familiarity alone can backfire: school desegregation dropped children into competitive classrooms and often increased prejudice. Muzafer Sherif's summer camp study created hostility between two groups of boys and ended it only with tasks requiring cooperation, and Elliot Aronson's jigsaw classroom, where each student holds one piece of the material, built friendships across ethnic lines. Police use cooperation in good cop, bad cop. Association is the last factor: people blamed a weatherman for bad weather, Gregory Razran found statements seen while eating became more liked, and fans bask in reflected glory, saying "we" won and "they" lost. The defense is to notice liking a seller more quickly or deeply than the circumstances warrant, and then to separate the person from the deal.

Cialdini fills in the evidence. In a Pennsylvania study, attractive defendants were twice as likely to avoid jail, and in a staged negligence trial a defendant better looking than his victim paid an average of $5,623, against $10,051 when the victim was the more attractive. Students dressed like the requester gave him a dime for a phone call more than two-thirds of the time, against less than half when dressed differently. People prefer the mirror image of their own faces because it is the version they see every day, and a little-known candidate in Ohio won after changing his name to Brown. Carlos, a shy Mexican American boy in a jigsaw group, was teased until his classmates realized they needed his piece of the material to pass, and within weeks they saw him as a friend. In Cialdini's own study, Arizona State students who had just failed a rigged test said "we" about a victory 41% of the time and about a defeat 17% of the time; students who had done well said it about equally, 25% and 24%. A reader who switched long-distance companies so a friend could save on calls ended the chapter, and an MCI salesperson told Consumer Reports the calling circle worked nine out of ten times.

"Few people would be surprised to learn that, as a rule, we most prefer to say yes to the requests of someone we know and like."

Chapter 6Authority: Directed Deference

In Stanley Milgram's experiments, ordinary people playing the teacher were told to shock a learner for every mistake. Although the learner screamed and begged, about two-thirds pulled every one of the 30 switches up to 450 volts; experts had predicted that about one person in a thousand would. Sex, ignorance of danger and sadism were ruled out, and when the researcher told teachers to stop while the victim urged them on, 100% stopped. Milgram concluded that the cause was a deep sense of duty to authority, which societies train into us because ordered authority is valuable.

Obedience is often automatic, which is where it goes wrong. Cohen and Davis describe a nurse who put eardrops in a patient's rectum because a doctor abbreviated "right ear" on the prescription. When a stranger phoning as a doctor ordered nurses to give 20 mg of an unauthorized drug whose maximum dose was 10 mg, 95% started to do it. Symbols work as well as substance: titles (an actor who played a doctor sold Sanka; a man introduced as a professor was seen as two and a half inches taller than as a student), clothes (Leonard Bickman's requester in a security guard uniform got 92% compliance against 42%, and three and a half times as many pedestrians followed a jaywalker in a business suit) and trappings such as luxury cars. Cialdini's defense is two questions: is this authority truly an expert, and how truthful can we expect the expert to be here? He warns that experts build trust by seeming to argue against their own interests, like the waiter Vincent, who steered large tables to slightly cheaper dishes and then sold them costly wine and dessert.

Cialdini adds that people consistently fail to predict authority's pull. In one Milgram variation, two researchers gave contradictory orders and every subject stopped. College students guessed that 50% of people would obey Bickman's requester in street clothes, close to the actual 42%, but guessed 63% for the uniform when the real figure was 92%. In the San Francisco Bay Area, 50% of drivers stuck behind a stalled luxury car waited without honking, while nearly all honked at an economy car and two rammed its bumper. S. Brian Wilson lost both legs when a train carrying military equipment did not stop for protesters, and the crew, following orders, later sued him. A reader's report describes a consignment dealer who told him to ask $3,500 for a car he valued at $3,000, then repeatedly asked him to cut $200 for buyers who never materialized.

"When in a click-whirr mode, we are often as vulnerable to the symbols of authority as to the substance."

Chapter 7Scarcity: The Rule of the Few

Cialdini decided to tour the newly renovated Mormon temple in Mesa only because non-members would never again be allowed into its inner sector. Opportunities seem more valuable as they become less available, and people are more moved by potential loss than by equal gain. Sellers use limited numbers and deadlines, and an appliance store he studied told interested couples the model was sold out, then asked them to commit to buying it if one could be found. A boiler room operation took $18,000 from an 81-year-old retiree by offering, withdrawing and re-offering an investment.

Scarcity draws power from the shortcut that rare things are usually better and from psychological reactance, Jack Brehm's term for our response to lost freedoms, seen in two-year-olds who reach for the toy behind a barrier and in the Romeo and Juliet effect, documented in a study of 140 Colorado couples whose love grew with parental interference. Miami residents rated banned phosphate detergents as better products, students became more opposed to coed dorms after a speech against them was banned, and juries told to ignore a driver's insurance raised awards further. A beef importer's customers bought six times as much when told of a coming shortage through exclusive information.

Stephen Worchel's cookie study adds that newly scarce items are valued more than ones always scarce, which James C. Davies uses to explain revolutions that follow improvement and then a sharp reversal, and that items made scarce by competing demand are valued most. ABC paid $3.3 million in the first open auction for a movie's TV showing, more than it could recover. Cialdini's brother Richard sold used cars by scheduling every buyer for the same time. The defense is to treat rising arousal as a signal to stop, then ask why you want the item: scarce cookies were rated more desirable, but they did not taste any better.

The loss framing shows up in health messages: pamphlets that told women what they could lose by skipping a monthly breast self-examination worked better than ones describing what they could gain. Collectors prize flawed stamps and coins because the flaw makes them rare. When Kennesaw, Georgia required every adult resident to own a gun, the buyers who flocked to its gun shops were nearly all from out of town. In a Chicago jury study, a driver who mentioned his insurance was ordered to pay $37,000 against $33,000 without it, and when the judge ruled the insurance inadmissible the award rose to $46,000. Davies cites the gains made by Black Americans after World War II, when family income rose from 56% to 80% of comparable white families' income, followed by a slide to 74% and the riots that followed, and Cialdini adds the Soviet coup of August 1991, which collapsed in three days when people who had been given new freedoms took to the streets. In the Poseidon auction, CBS president Robert Wood bid up to $3.2 million before losing, and said afterward that the fever caught him.

"The joy is not in experiencing a scarce commodity, but in possessing it."

EpilogueInstant Influence: Primitive Consent for an Automatic Age

Cialdini returns to his theme with an exchange from a 1960s talk show: the host told Frank Zappa that his long hair made him a girl, and Zappa replied that the host's wooden leg made him a table. We often decide using one representative piece of information, which normally serves us but can make fools of us. People have the most capable brains on the planet, yet they have built a world so complex and fast that they must increasingly respond like animals, to single cues. John Stuart Mill, who died in 1873, was reputed to be the last man to know everything there was to know; Cialdini adds that 90% of all scientists who have ever lived are working today.

Compliance professionals who play fair by the six principles are partners in an efficient exchange. The enemy is anyone who counterfeits the cues, and Cialdini urges counterattack: refuse programs with canned laughter, give nothing to a bartender who salts his own tip jar, and walk out of a line staged to fake a club's popularity, telling others why.

"I am at war with the exploiters. We all are."