Influence

This is the book that turned persuasion into a science anyone can read. If you buy, sell, negotiate, fundraise, or simply get talked into things you later regret, Cialdini hands you the exact scripts used against you. Marketers, negotiators, and skeptics will find it indispensable; so will anyone who has ever donated a dollar because someone handed them a flower.

1. 1Chapter 1, Weapons of Influence

   The jewelry that sold only when it cost double

   An Arizona jewelry store owned by a friend of Cialdini's sat on a batch of turquoise that would not move. Heading out of town, the owner left a note for an employee: cut the prices in half. The employee misread the scrawl and doubled them instead. Customers snapped up the entire stock, paying premium prices for pieces they had ignored a day earlier.

   The idea

   Cialdini cites Harvard social psychologist Alfred North Whitehead: 'Civilization advances by extending the number of operations we can perform without thinking about them.'

   Try this: This week, before any purchase over $50, pause and ask what specific evidence you have for the item's quality besides its price tag.

2. 2Chapter 1, Weapons of Influence

   Because I have to make some copies

   In a study by Langer, Blank, and Chanowitz (1978), people waiting to use a photocopier were asked: 'Excuse me, I have five pages. May I use the Xerox machine because I'm in a rush?' 94% complied. With no reason ('May I use the Xerox machine?'), only 60% complied. With a placebic reason ('because I have to make some copies'), 93% complied, showing the power of the word 'because'.

   The idea

   The contrast principle: a salesperson should sell the expensive suit first; after spending a large amount on the suit, the price of the sweater (or accessories) seems smaller by comparison. The principle applies across sensory experiences—lifting a light object after a heavy one makes it feel lighter.

   Try this: When someone gives you a reason that explains nothing, say so out loud and ask what the actual reason is.

3. 3Chapter 1, Weapons of Influence

   The mother turkey and the cheep-cheep

   Ethologist Konrad Lorenz discovered that a mother turkey's maternal behavior is triggered almost exclusively by the 'cheep-cheep' sound of her chicks. A stuffed polecat—a natural enemy of the turkey—was pulled toward a mother turkey while playing the 'cheep-cheep' recording; she gathered it under her wing. When the recording stopped, she attacked it.

   The idea

   The turkey is not stupid. The shortcut works nearly all the time, which is why natural selection built it in. The danger is not having automatic behavior — it is meeting a trickster who knows the trigger. Cialdini's argument across the whole book is that humans run on similar recorded triggers, and compliance professionals have learned to press them on demand.

   Try this: Notice one situation where you say yes automatically, and identify the trigger word or gesture that sets it off.

4. 4Chapter 2, Reciprocation

   Ethiopia sends $5,000 to Mexico

   In 1985, Ethiopia—suffering severe drought and famine—sent $5,000 to Mexico after the Mexico City earthquake. Cialdini explains this as repayment: Mexico had sent aid to Ethiopia in 1935 when it was invaded by Italy.

   The idea

   The rule of reciprocation states that we should try to repay, in kind, what another person has provided us. The rule is so strong that it can produce a 'yes' to a request that, except for an existing feeling of indebtedness, would surely have been refused.

   Try this: Track every unsolicited gift or favor you receive this week, and decide consciously whether it deserves repayment.

5. 5Chapter 2, Reciprocation

   A flower you cannot refuse

   The Hare Krishna Society used a fund-raising tactic at airports: a member would press a flower or small gift into a passerby's hand, refuse to take it back ('It is our gift to you'), and only then request a donation. The tactic was so effective that the organization gained significant funds, and airport authorities eventually restricted the practice.

   The idea

   The gift does not need to be wanted, asked for, or even kept; it only needs to be given. Once it is in your hand, the obligation is in your head. Cialdini's point is that the rule can be triggered by a deliberate first move, which turns an ancient social glue into a fundraising machine, and the defense is to redefine the gift as a sales device rather than a gift.

   Try this: If someone gives you something unsolicited and then asks for money, mentally reclassify the gift as a sales tactic and walk away.

6. 6Chapter 2, Reciprocation

   Ask big, retreat, get twice as much

   The rejection-then-retreat technique: researchers asked college students to chaperone juvenile delinquents on a zoo trip; 17% agreed. Another group was first asked to serve as unpaid counselors for two years (all refused), then asked about the zoo trip; 50% agreed. The technique also increased the likelihood that subjects would show up for the agreed commitment. In the same rejection-then-retreat study, subjects were also asked to sell raffle tickets. Those who received the larger-then-smaller request bought twice as many tickets as those who received only the smaller request.

   The idea

   The technique works partly because the requester's apparent concession triggers a reciprocal obligation to make a concession.

   Try this: When a negotiator drops from a huge ask to a smaller one, treat the drop as a tactic, not a favor, and price the smaller ask on its own merits.

7. 7Chapter 3, Commitment and Consistency

   Watch my things: 19 of 20 intervene

   In a 1975 study by Thomas Moriarty on a New York City beach, a confederate left a radio on a blanket and walked away; a second confederate pretended to steal it. When the owner had previously asked the neighbor to 'watch my things,' 19 of 20 subjects intervened. When no such request was made, only 4 of 20 intervened.

   The idea

   The sentence worked because it created a tiny commitment, and consistency pressure did the rest. Once you have said you will watch someone's things, standing by while they are stolen would make you the kind of person who breaks his word. Cialdini shows that commitments need not be grand; a small spoken agreement can summon behavior that nothing else would.

   Try this: When you want help, get an explicit yes, even a one-word one, rather than assuming people will act on their own.

8. 8Chapter 3, Commitment and Consistency

   The 3-inch sign that filled 76 percent of lawns

   The foot-in-the-door technique, illustrated by Freedman and Fraser (1966): California homeowners asked to display a large, ugly 'Drive Carefully' sign on their front lawns complied at only 17%. Another group was first asked to display a small 3-inch sign; nearly all agreed. Two weeks later, 76% of those who agreed to the small sign agreed to the large one.

   The idea

   The foot-in-the-door technique works because of self-perception: your own small act becomes evidence about who you are, and future requests are judged against that new identity. What surprises people is how little the first step has to cost. A 3-inch card in a window is enough to triple compliance with a billboard on your lawn two weeks later.

   Try this: If you want a big favor later, start this week by asking for something so small it is almost impossible to refuse.

9. 9Chapter 3, Commitment and Consistency

   Written words broadcast to fellow prisoners

   During the Korean War, Chinese captors used a step-by-step technique on American POWs: they were asked to write down small, seemingly innocuous statements (e.g., 'The United States is not perfect'), then gradually escalated to anti-American essays. These written statements were later broadcast to other prisoners, reinforcing the writer's new self-image.

   The idea

   Written commitments are especially powerful.

   Try this: Write down a goal and show it to someone; the paper will pull your behavior toward it more than a private resolution would.

10. 10Chapter 3, Commitment and Consistency

    The Christmas toy that vanishes from the shelves

    Toy manufacturers use a commitment strategy before Christmas: they advertise a particular toy heavily but undersupply stores. Parents promise the toy, find it sold out, and buy substitutes. After Christmas, the company advertises the toy again, and parents—committed to their promise—buy it. Cialdini reports that sales of both the substitute and the originally promised toy increase.

    The idea

    The trap is not the shortage; it is the promise. Once a parent has told a child yes, consistency pressure keeps the commitment alive long after the shopping trip ends. The tactic works because the commitment is made in an emotional moment and the fulfillment is deferred, giving the company a second selling season from a single promise.

    Try this: Before promising a child a specific gift, check that it is in stock; if it is not, promise a category, not an item.

11. 11Chapter 3, Commitment and Consistency

    700 percent more volunteers from one phone call

    In a study by social psychologist Steven J. Sherman, residents of Bloomington, Indiana, were called and asked to predict what they would say if asked to donate three hours to the American Cancer Society. Wanting to appear charitable, many said yes. Three days later, a different person called asking for volunteers; 700% more volunteers agreed compared to a control group.

    The idea

    Asking someone to predict their behavior is a disguised way of getting a commitment, because the answer is public to the self and consistency pressure applies to it. The caller three days later was a stranger, so no relationship or guilt could explain the jump. The prediction alone had converted residents into volunteers.

    Try this: Ask a colleague to predict whether they will complete a task by Friday; the prediction itself raises the odds.

12. 12Chapter 4, Social Proof

    Canned laughter and the smoke nobody reports

    Canned laughter on television comedies exploits this principle; experiments show that audiences laugh longer and more often when they hear others laughing, even if the laughter is artificial. In a smoke-filled-room experiment by Latané and Darley, a student alone in a room when smoke began pouring from a vent reported it 75% of the time within 6 minutes. When three naive subjects were together, only 38% of the groups reported it. When one confederate ignored the smoke, only 10% of subjects reported it.

    The idea

    The principle of social proof: 'We view a behavior as more correct in a given situation to the degree that we see others performing it.'

    Try this: In an emergency among strangers, pick one person, point at them, and assign a specific action; do not address the group.

13. 13Chapter 4, Social Proof

    Thirty-eight witnesses, thirty-five minutes

    The 1964 murder of Kitty Genovese in Queens, New York: thirty-eight witnesses reportedly watched or heard the attack over 35 minutes without intervening or calling police. Cialdini explains that the bystander effect and pluralistic ignorance caused each witness to assume others would act, or that the situation wasn't an emergency because no one else was reacting.

    The idea

    In an unfamiliar or ambiguous situation, we all look to each other for evidence of what is real, and everyone looking at everyone else can produce a collective shrug in the face of catastrophe. The witnesses were not indifferent; they were reading each other. The fix is to break the loop by being the first to define the situation.

    Try this: If you see something ambiguous that could be an emergency, act on your own read rather than waiting to see what others do.

14. 14Chapter 4, Social Proof

    910 people drink the Flavor Aid

    The Jonestown massacre of 1978 in Guyana, where 910 members of the Peoples Temple died after drinking cyanide-laced Flavor Aid. Cialdini explains that social proof was a key factor: the group had moved from San Francisco to an unfamiliar jungle, and in the absence of familiar social cues, members looked to each other and to leader Jim Jones for guidance on how to behave.

    The idea

    The Werther effect: sociologist David Phillips found that after a highly publicized front-page suicide story, an average of 58 more people than expected die in commercial airline crashes within two months. The increase is greater when the suicide story involves multiple people.

    Try this: When you are new to a group or place, deliberately keep one trusted outside perspective available before adopting local behavior.

15. 15Chapter 5, Liking

    The Tupperware party and the candidate's face

    The Tupperware party exploits the liking principle: the purchase decision is based not solely on product quality but on the social bond with the host, a friend or neighbor. Researchers Frenzen and Davis (1990) found that the strength of the social tie between host and guest was twice as important as the guest's attitude toward the product in predicting purchase. A 1974 Canadian federal election study found that attractive candidates received more than two and a half times as many votes as unattractive candidates. Yet 73% of voters denied that appearance influenced their vote. Similarity and car sales: salespeople were trained to notice items in a customer's trade-in (camping gear, golf clubs) and mention shared interests.

    The idea

    We say yes to people we like, and liking is manufactured by similarity, familiarity, and flattery more than by merit. The unsettling part is the denial: voters genuinely did not know their faces had voted. The defense is to separate the pitch from the pitcher, asking whether you would want the offer if a stranger delivered it.

    Try this: Before agreeing to buy from a friend's party or a charming salesperson, ask what you would decide if the same offer came from someone you dislike.

16. 16Chapter 6, Authority

    Place in R ear

    A doctor prescribed ear drops for a patient's right ear infection, abbreviating the order as 'place in R ear.' The nurse interpreted 'R ear' as 'rear' and administered the drops into the patient's anus. Neither the patient nor the nurse questioned the treatment because of the doctor's authority. In a 1966 study by Hofling and colleagues, a man identifying himself as 'Dr. Smith' called 22 nurses on hospital wards and ordered them to administer 20 milligrams of Astroten to a patient. The drug was unauthorized, the dose was double the maximum on the label, and hospital policy forbade phone orders. Yet 95% of nurses (21 of 22) proceeded to administer it before being stopped.

    The idea

    Milgram's obedience experiments at Yale University: a 'teacher' was instructed by an experimenter in a lab coat to deliver increasingly severe electric shocks to a 'learner' for wrong answers. Despite the learner's screams and eventual silence, 65% of subjects delivered the maximum 450-volt shock, labeled 'XXX' on the shock generator.

    Try this: When an instruction comes with a title attached, ask yourself what you would do if a stranger with no title gave the same instruction.

17. 17Chapter 7, Scarcity

    The last two cookies in the jar

    In a 1975 study by Stephen Worchel and colleagues using chocolate chip cookies, subjects rated cookies from a jar with 10 cookies as more desirable than cookies from a jar with 2 cookies. However, cookies that became scarce (the jar changed from 10 to 2) were rated as the most desirable of all—more than cookies that were consistently scarce.

    The idea

    The scarcity principle: 'Opportunities seem more valuable to us when their availability is limited.' The idea of potential loss plays a large role in human decision making; people are more motivated by the thought of losing something than by the thought of gaining something of equal value. The 'Romeo and Juliet effect,' explained through reactance theory (Jack Brehm): when parents interfere with a teenage romance, the couple's feelings for each other intensify. A study of 140 Colorado couples found that parental interference was associated with increased love and commitment; when interference weakened, so did the romantic feelings.

    Try this: When an offer stresses what you will lose by waiting, write down what you would pay if the item were freely available, and compare.

Anyone who buys, sells, negotiates, fundraises, or wants to understand why they agreed to things they never planned to. Essential for marketers and negotiators, and equally for the rest of us who want to keep our yeses our own.

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