Influence – Robert Cialdini

A few points before the main notes. As is acknowledge throughout the book most of the tendencies noted are genuinely useful most of the time. Reciprocating actions helps build trust, accepting parental authority on what is dangerous when young is likely a useful activity. It is mainly when taken to new areas or pushed to extremes that a lot of these behaviours seem silly or misguided. Another point is how simple many of these influences seem while reading the book. This is actually an endorsement of how well written the book is as it is frequently pointed out that these influences were missed by many great thinkers and/or took teams of people to be able to aptly explain. It is therefore worth being extra vigilant of hindsight bias as one reads through the book thinking that these ideas are so simple as to not warrant close attention. Lastly in my notes I do not quote large amounts of figures or reference studies. These are all in the main book that I would strongly one reads and I left them out mainly for succinctness here.

Weapons of influence

Humans as well as most other animals seem to have a number of fixed action patterns in built to help navigate life’s complexities. most of the time these work well but occasionally either by accident or intention they can be manipulated. For example just by providing a reason to someone they are more likely to comply with a request even if the reason gives no useful information. These fixed action patterns lead to trigger responses. for example seeing a higher price and instantly ascribing a higher level of quality to it. Another example is a company sending out coupons that gave no savings, and yet still got a similar reaction. People seem to associate coupons with better value and act on this with little consideration. In more unscrupulous examples some real estate agents may show potential buyers undesirables houses at inflated prices to take advantage of the contrast principle. As technology evolves faster our capacity to process information is likely to be increasingly inadequate and we will likely find ourselves more often in the position of the lower animals only this time we will have created our own deficiency. Below the set up is as follows. A paragraph introducing the particular influencer, then a number of examples and finally points on how to avoid the influencer.



Reciprocity is a beneficial trait for a society to have. It made a massive difference in the ability to produce social advances as one individual could give away a variety of resources without actually having to give it away, they knew they would get something back and not be exploited . It is so powerful that it can completely overcome whether a person likes you or not as seen in one experiment where an actor brought someone a coke and then later asked them to buy raffle tickets. One reason it is so effective is that there is a strong cultural pressure to reciprocate gift, even an unwanted one and most people find it very uncomfortable to be in state of obligation with some willing to do a larger favour that the one we received just to get out of the feeling. This distaste is not just in our heads, there is a culturally strong distaste for those who fail to conform to reciprocity. Also those who break rule in reverse e.g give without allowing recipient an opportunity to repay also disliked (Gergen et al 1975). As such people will often avoid asking for needed favour if they are not in position to repay. So what are some common ways this is used to influence? The rejecting then retreat technique allows the asker to seem to be backing down from their true want and so we reciprocate by being more likely to accept their second suggestion. This is likely to fail however if the first set of demands is so extreme as to seem unreasonable. This suggests that a gifted negotiator should have their initial position exaggerated enough to allow for reciprocal concessions but not so outlandish as to seem illegitimate (this technique also benefits from the contrast principle view of seeing a smaller request in the light of a larger one). Another important point is that people who have been victims of RTR seem to prefer the outcomes and believe they had more control in getting there. It is worth noting that after reading about reciprocation the RTR seems to make a lot of sense but Cialdini himself had to gather research assistants to come up with ideas as to why he had just brought cookies from a boy scout he didn’t want. One extra benefit of RTR is that due to the social pressure to not feel indebted the effects of compliance can be for events quite a way into the future 


  1. Krishna’s employ donation-request procedure that engages rule of reciprocity. Before they request donation they give target a gift and refuse to take it back.
  2. During 1992 presidential race famous actress Sally Kellerman gave her name to the Democratic candidate Jerry Brown, when asked why she said that 20 years ago he was the only friend who showed up to help her move. This shows long lasting impact of reciprocity.
  3. Indiana supermarket put out cheese and invited customers to cut off slivers for themselves as free samples. This trust in customers lead to huge increases in amount of cheese brought.
  4. Amway used a product called the BUG, collection of products in specially designed tray, that is left with customer for 24-72 hours at no cost. On average people purchase half of the BUG when it is picked up.
  5. People were asked if they would look after juvenile delinquents on a trip to the zoo. In first group this was all that was requested and 17% accepted. The second group were first asked to give 2hrs a week for 2 years, then they were asked to chaperone and 3 times as many agreed.
  6. Some TV writers deliberately insert lines into script for censors to axe so that they can get the lines they really want in. On Happy Days the biggest censorship fight was over the word “virgin” so they put it in 7 times hoping they would only cut it 6.
  7. Only one member of watergate group expressed opposition to the proposal when he heard it. He was also the only one to have not been at the 2 other meetings that had much more outlandish proposals, the theory is that the people in these two meetings felt like they had to give the prosper something after rejecting him twice.


Try to accept offer for what it fundamentally is not what it is represented to be and if you determine it was a reciprocity tactic then you will not feel obligated to follow reciprocity rule. This involves mental redefinition e.g you are not getting a gift but a sales device.

Commitment and consistency


we have a nearly obsessive desire to seem consistent with what we have already done. If someone can get you to take a stand and make a commitment that will be enough to get consistency most of the time, even if the commitment seems trivial. this is part of the reason the author is rarely willing to sign petition due to potential influence on future actions. For example after hearing they were considered a charitable person people are much more likely to give. Consistency is not necessarily a bad thing though and the full RWE puts it well, “a foolish consistency is the hobgoblin of little minds”. This influencer can is especially strong when the declaration comes in written form, due to this to cut refunds many companies get customers not sales people to fill out sales agreement. Part of why writing can be such a consistency booster is the public nature of it. this is part of the reason why hung juries are more frequent if jurors hand to express opinion with visible show of hands rather than secret ballot. This is also one good reason in hindsight for the founding fathers of America to use anonymous voting when creating the constitution. As mentioned before justification will often creep in with commitment and this can help explain why groups that have hazing and other such initiations are truly tighter than they may otherwise be. 


  1. Why would many people sign up to transcendental meditation after a friend of author made many logical arguments against it in front of the? Their response, “if I’d gone home I would have started to think about it and never have signed up”. These people were desperate and had erected walls against reason as soon as reason had been provided making them more resolute in their decision
  2. How could toy companies take advantage of parental consistency to boost january sales? If these companies ‘ran out’ of most popular toy before chrismas but after most parents agreed to buy it for their child then the parent would be forced to buy a replacement gift. However, the commitment to the child is still there and so when in January the toy becomes back in stock it is likely the children want the promise of the toy fulfilled.
  3. When people asked to predict what they would say if asked to spend 3hrs fund-raising for cancer charity this lead to a 700% uptake in volunteers when 3 days later they were asked to volunteer 
  4. Freedman and Fraser did experiment asking for a public service billboard to be installed on front lawns. almost all refused. another group 2 weeks earlier had been asked to display a small 3 inch square that read be a safe driver. 76% offered their gardens. this shows us that it may be prudent to be careful about agreeing to trivial requests 
  5. Someone left their belonging on a beach and a person came and stole them. In normal circumstances very few people reacted, but when people around spot were asked to “watch my things” 19 out of 20 subjects acted.
  6. Why are we asked how we are feeling today on phone calls? One reason may be genuine politeness but is there another reason? One answer may be that they want you to respond with polite comment so you publicly state you are doing well and because of this it is easier for person to ask you for money for those who are not doing well
  7. Deutsch and Gerard ran test where students were given some information and some were asked to write initial guess down, sign it and hand it in, some were asked to write it down and then erase it and some were told to not write anything down. those who didn’t write anything least loyal to their choices.
  8. Why do many companies run testimonial contests with stunningly large prizes to get as many people as possible to go on recored liking the product? They get huge numbers of people to commit on paper to loving the product. 
  9. Person wanting to quit smoking wrote list of people they wanted to respect them and then gave them all a business card saying I promise you I will quit smoking
  10. How could Chinese captors how to get POW to give up military information. start small and built. They wanted to get prisoners to writ very mildly anti-American comments e.g The USA is not perfect or list some problems in America and then sign it. A written declaration was most important as it was both physical evidence and could be shown to others. This not only made the writer believe what they wrote more than if they had just said it but people often believe statement reflects true attitudes of person who made it. They also held essay competitions with writing prize occasionally given to essay that supported the USA but bowed once or twice to Chinese view. people began to shade their essays a bit towards communism. The prizes for these competitions were rarely large as they wanted men to own what they had done with no ways out. 
  11. Low ball technique – very good price offered on car but not genuine, purpose is to get people to decide to buy one of the dealers cars
  12. People were told that if they agreed to save energy they would have their name published in the local paper.However, a letter came saying that it would not be possible anymore, did people revert back to old habits, no. once they had made commitment to saving energy that commitment generated its own support 
  13. consistency gives us insights into how to treat young children. You should never bribe or threaten children to do things we wan them to truly believe in. if we want child to not lie as they think it is wrong we must give reason strong enough to get them to be truthful most of the time but not so strong as to make it seem the reason for truthfulness. give reason that will initially produce desired behaviour and will later allow child to take personal responsibility. Wise parents provide highly consistent information (this also helps overcome psychological reactance were the child used to some new freedom has it taken away)


to try and get around this ask yourself if you would make the same choice again and look for the first flash of feeling

Social proof


people are persuaded more by the actions of others than by any proof we can offer. This effect is most prevalent in situation of high uncertainty, for example the inhabitants of Jones Town who moved into the rainforests. This can lead to a very powerful force called pluralistic ignorance, where there is a tendency for everyone to look at what everyone else is doing and base their decision on that. This helps explain the bystander effect that occurs when we are less likely to help someone in a group than when we are alone. The principle of social proof also helps to explain how large groups are influenced as as long as you can influence a small but dogged minority then these people can influence others by their actions and so on. This is even more effective if the people involved are similar as we are more likely to follow the lead of someone more like us. This has been shown with children being more likely to get over fears if they see videos of people their own age engaging in the same behaviour. 


  1. Bartenders often salt their tip jar to simulate tips from other customers
  2. some churches have ringers who are to come froward to give donations
  3. Clubs make visible social proof for their quality by creating long waiting lines outside when there was plenty of room inside
  4. immediately following failure of prophecy rather than religions cults disbanding they became strengthened, why is this? For many irrevocable steps were taken in joining cult and so they must believe even more in the face of adversity to make their actions not seem for nothing. they began to try to recruit members at a frantic rate as if others believed in their cause still it must still be worthwhile
  5. The peoples temple –  act that most contributed to members mindless compliance was relocation to jungle country with unfamiliar customs. we have been told that social proof is most powerful in uncertain situations, do we think the people would have killed themselves if they had stayed in san francisco 
  6. claquing- people leased themselves to operas to clap and simulate appreciative audience
  7. type of freeway accident occurred when pair of cars would simultaneously merge into other lane. within seconds many other drivers were doing the same until a crush occurred
  8. on racetrack – in order to lower odds and make more money some bettor sway public opinion to bet on a bad horse. they will pick a horse with long odds and the minute the windows open they will lay down a large bet on the horse and people will see that the early betters have decided a favourite and follow

Bystander effect

  1. Catherine Genovese was chased and attacked for 35 minutes as 38 of her neighbours watched the events of her death without lifting a finger to call the police, why? One of the leading explanations at the time was that people didn’t care, that the city caused apathy. However one psychologist put forward the unlikely explanation that 38 witnesses did nothing because there were 38 witnesses. They argued that the personal responsibility had been reduced and as such people were at the mercy of pluralistic ignorance. We should be careful about thinking the cause of bystander effect obvious, there were entire books written by intelligent people without ever thinking about it 
  2. Experiment where someone feigned epileptic seizure. got help 85% of time when 1 bystander but only 31% when there were many. Similarly when people saw smoke coming from under a door 75% reported it when alone. in a 3 person group it was reported 38% of the time. when 3 person group had 2 people instructed not to react only 10% reported
  3. once witnesses are convinced there is an emergency aid is very likely. but if not clear help more likely by lone bystander

Effects of similarity

  1. We get average person on the street testimonials on TV a lot as this makes it seem like there are people just like us enjoying the products.
  2. Nursery school children who were terrified of dogs watched a little boy playing happily with a dog for 20 minutes a day and then 67% of them were willing to climb into a pen with a dog. A similar experiment was done with children who were not engaging much with others only this one had eleven different children in different nursery settings each beginning with child solitary and then joining activity to everyones enjoyment. This proved very effective and the real life isolates began to interact. Again a similar thing happened with the authors son who feared swimming but after going to camp said, well I’m 3 and the other children were 3 and they can swim without rings so so can I
  3. Wallet was placed on the ground with letter saying the wallet was found earlier and there was intention to return it and was happy to help. some fo the letters written in standard english by seemingly average Americans and some written in broken english. 35% of wallets returned by dissimilar writers and 70% of wallets returned by similar writing. Would it be useful to carry a stock polaroid in your wallet seeming to show a loved one?
  4. Why after certain highly publicised suicide stories does number of people who die in commercial plane crashes increase 1000% and the number of automobile fatalities shoots up? One explanation is that the same social reasons one person committed suicide cause others to die accidentally e.g some people may kill themselves in stressful times others may be angry/distracted and die from that. However commercial airline fatalities only shoot up in region story is highly publicised. Another potential reason is a bereavement theory that suggests many people thrown into state of shocked sadness and become careless. But reports of suicide victims who die alone leads to single fatality wreck frequency to increase only. suicide plus murder leader to multiple fatality wrecks. Werther effect (the sorrows of young Werther) the protagonist commits suicide and this lead to a wave of emulative suicides across Europe. In 1986 within 2 months of front page suicide story average of 58 more people than usual killed themselves


One of the best defences is to recognise when data is in error/when evidence has been falsified (testimonials). There are two useful questions to ask yourself:

  1. How much more informed are other people around me to what is going on?
  2. Would I act differently if it was only me in this situation?

Specifically to help in an emergency when pluralistic ignorance is prevailing your best bet is to isolate an individual and use the word “HELP”. Once people start to help social proof can then work in your favour.



Liking people often gets us to act in ways we would normally avoid, or at least be far slower to react to and more considerate of. This is particularly potent when instead of a stranger it is a friend who a company has used to sell to us or they come armed with the name of a friend you would be helping. It is also particularly strong if the person is similar to us e.g opinions, dress, traits or background. Liking will often happen subconsciously and can be induced by mimicry or them simply telling us they like us even if given the situation this should have no bearing. We will often not be aware of it and may even resent the idea it is influencing us. any type of segregation often leads to a we vs them attitude however this is easy to overcome by forced cooperation where to stay hostile will be to the detriment of all. The principle of liking can be enhanced by the contrast principle where you are first exposed to someone you do not like e.g good/bad cop and can be coupled with the reciprocity principle to great effect where someone doing something on your behalf can lead to you liking them more. The content of our speech will also willingly or not lead to people liking us where those who say negative things will be perceived less fondly than those who do otherwise. Also people will often associate themselves with something that is liked e.g a winning sports team using the pronoun “we” or some other successful individuals (especially when they are not doing so well) but will distance themselves from things that are unfavourable.


  1. Tupperware’s party: by providing hostess with percentage of the take lead to customers buying from friends. everyone gets small gift before buying starts (reciprocity) and everyone must state publicly the benefits of Tupperware (commitment), and once buying begins there is element of social proof 
  2. Salesperson will often try to get you to suggest friends who would like service as they are less likely to turn them away. Or on the flip side a long distance call company had a Family calling circle and by joining you would save your friend 20% on all calls he makes to people in his calling circle provided they are MCI subscribers, much more likely to join.
  3. Joe Girard was a very successful Chevy dealer who had a ritual of sending his 13,000 contacts each month a greeting card with a personal message that changed month to month, but the message on the front never change, it was “I like you”.
  4. What were the effects of school desegregation? On the whole they were negative as continued exposure to person or object under unpleasant conditions such as conflict, or competition leads to less liking. What were some alternative approaches? Experimented with forms of learning based on cooperation not competition such as jigsaw classroom, each person in a team has only one part of information and must give it to others if they are all to pass test. you can tease someone in group if you want to but it’s not going to help you pass the test. Another example of using cooperation to make kids get along is at summer camp, simply separating people into two residences was enough to bring about we vs they. to combat this they used a series of exercises where competition would have harmed everyone such as a truck being stuck, or that a movie was available to rent but everyone needed to club their money together
  5. good cop/bad cop – fear of long incarceration instilled by bad cop and we have contrast principle where good cop seems especially reasonable and they have intervened on your behalf so we have the reciprocity principle acting
  6. Razran’s Luncheon technique: people fonder of things they experience while eating
  7. when a sports team wins people often use they pronoun “we” e.g “we’re number one” when team loses it is “they”
  8. When it comes to ugly inmates prisons reoffending rates would be better in instead of costly rehabilitation they provided plastic surgery as this seems to be at least as effective and less costly. However Stewart 1980 argues against this saying that making ugly criminals more attractive may not reduce chances of crimes but reduce chance of going back to jail
  9. attractive candidates received twice as many votes as unattractive candidates. People are reluctant to admit this though and in Canada 73% said they were not swayed by physical appearance 


Very hard to ignore but be aware when undue liking has been created or when we find ourselves liking the practitioner more deeply and faster than we expect and try to mentally separate the person and the thing. Also keep in mind that we typically underestimate amount similarity makes us like someone



for many things deferring, somewhat, to authority has had its benefits. As a child your parents and teachers are likely to know more than you do. We depend on superior judgement of doctors and lawyers in their relative fields. A multilayered system of authority has immense benefits as well as it allows for the development of sophisticated structures, resource provision, trade and defence. We seem fairly good at predicting compliance rate when there is no authority figure however we seem to largely underestimate compliance rates when in the presence of authority figure. This influence not only can leave us open to exploitation but can lead to serious dangers, in the case of nurses complying blindly with doctors. It is also not even true authority that we submit too but the appearance often seems to be enough. When thinking about how to change the opinion or practices of a group it may therefore be most effectual to influence the dominant person and the rest will follow e.g with groups of monkeys.


  1. Milgram’s experiment – most people estimated only 1-2% of those in the experiment would administer the highest shock, 65% actually did. However when scripts were shaped so the researcher in a lab coat was getting the electric shocks and asking for them to stop and the “victim” was the one telling the person to go on 100% stopped administering the shocks
  2. there is long established tradition for automatic obedience to doctors orders. in 1980’s for patient medication alone average hospital had 12% daily error rate
  3. strategy used by second hand car sellers is to tell you you have undervalued your car, seemingly going against their interests, and then set up deals that require you to knock a few hundred dollars off the price that keep falling through 
  4. when pedestrians asked to give dime to person in car park by person who was walking away. When they looked like normal person compliance was guessed to be 50% vs actual 42%. But when dressed as a guard, compliance was guessed at 63% vs actual 92%.
  5. Vincent the waiter example: He would change his style depending on what kind of group he was dealing with.
  • Families – he was effervescent and clownish directing remarks to children as much as to adults. Young couples on dates he was very formal and a bit imperious to intimidate the
  • young couple on date – would speak almost exclusively to young man and in a more superior manner so he would order and tip lavishly
  • older married couple – retained formality but dropped superior air for respectful orientation to both members of couple
  • Lone diners – he was friendly and conversational
  • Large parties – seemed to argue against his own best interests, no matter what first person ordered he reacted identically, furrowed his brow and hovered his hand over his order pad looking quickly for the manager and said “I’m afraid thats not as good tonight as normal, might I recommend ….” would recommend pair of items just cheaper. Diners felt he had done them a favour and so reciprocity rule. he was now in favourable position to increase size of tables order as he had put himself as authority as to current quality. He seemed a trustworthy informant by recommending dishes that were a bit less expensive. after food orders he asked if they would like him to suggest some wine, and he responded with excellent and costly choices and had similar actions with dessert with his rapturous descriptions of the items


Ask yourself is this person in authority truly an expert and how truthful can we expect the expert to be (what do they stand to gain from our compliance)



when we become aware of that an item is more scarce, or we perceive it to be scarcer, we seem to desire it more. This not only happens with physical items such as cars but with freedoms. Psychological reactance suggests that as opportunities become less available we lose freedoms and we hate to lose freedoms we already have. desire to preserve established prerogatives is centrepiece of psychological reactance explaining response to diminishing personal control so if something interferes with our prior access we will react against interference by wanting item more. It is not just scarcity that makes us desire something but especially recently scarce items and this is even more true when recent scarcity due to demand rather than supply reasons. double scarcity, that of saying that something will be scarce and also that the information on this is also scarce seems to have a particularly large effect as well, see Beef selling.


  1. Romeo and Juliet effect: couples with more parental interference commit to each other more and fall more deeply in love. 
  2. On the subject of children, it is very important for parents to know as as children age especially into toddlers and teenagers and gain senses of freedom we will likely see more resistance to rules and so should be very wary of being compatible with what is allowed and what isn’t
  3. Information: censuring information may make people both believe it and desire it more. This leads to the possibility that for individuals with unpopular positions, they can get more people on board by having their message restricted and publicise the censorship. A permissive free speech provision can help to minimise the chance that new political notions win support via irrational psychological reactance. This effect occurs even in the setting of a court room. In jury trials when evidence is introduced and then ruled inadmissible often more influential. Juries make larger payouts to people with insurance $37,000 vs $33,000 but if driver said they were insured and then evidence ruled inadmissible average award was $46,000. 
  4. Revolutions: We are most likely to find revolutions when we are in a period of improving economic and social conditions followed by a short sharp reversal. For example soviet union, Gorbachev granting new civil liberties under twin policies of glasnost and perestroika and the new KGB staged a coup to reinstate old order. new freedoms threatened and uprising was swift, massive and unitary that officials surrendered. had they been students of history they would likely have not been so surprised. should take away civil liberties slowly 
  5. Homeowners seem to react more when told how much they could loose from inadequate insulation more likely to insulate than those told how much they could save
  6. In appliance store they would find couple who looked interested in product and then tell them they had just sold the last unit. The couple would ask if they could go and check and the person would get them to commit that if there were any left they would buy it at a particular price
  7. Authors brother made money selling second hand cars using principle of scarcity. Each interested prospect was given the same appointment time. earlier arrival would assert his right and if he didn’t Richard would do it for him. “Excuse me but the other gentleman was here first so can I ask you to wait on the other side of the driveway until he’s finished and if he decides he doesn’t want the car or can’t make up his mind I’ll show it to you
  8. fake investment calls. First call, the opening. Second call, the great profits to be made but that it is no longer possible to invest. Third call, there is a chance again but you need to be quick
  9. children with toys, when barrier big enough to be true obstacle boys went straight for obstructed toy, when not large enough to be obstacles save response to both
  10. Timothy Brock, Howard Fromkin, “commodity theory”  – exclusive info more persuasive. A student of the Author sold beef and he gave out three sales presentations. Group 1 given standard sales presentation. Group 2 given standard sales presentation and told supply of imported beef likely to be scarce. Group 3 given standard sales presentation and told supply of imported beef likely to be scarce and that this information not generally known. Group 2 brought twice as much beef as group 1 and group 3 brought 6 times more


we should try to note when we are getting an emotional rush to own a good and then use this knowledge to ask ourselves why we want the good. if we want it for the shear act of owning it rather than using it then this may signal a scarcity issue.

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