Reciprocation Consistency Social Proof Liking Authority Scarcity

This is the psychology of compliance. Compliance practitioners - the people who need you to comply with their wishes - use the following principles to get what they want. Be it a salesperson trying to sell you a new car, or a toystore tricking you into buying things for your kids, or someone selling you raffle tickets. They do this all the time, without you noticing. Their livelihood depends on this. After all, if they aren’t good at it, they’d starve.

So, what can you do about it?

Like most cognitive biases, these principles lose their force once you start spotting them. We will examine each principle in its ability to produce this automatic, mindless compliance from people.

I didn’t think of all these principles. Nor did Dr. Robert Cialdini. But, he put them together into a masterpiece book called Influence: The Psychology of Persuasion. This post is my notes from the book, plus some examples. All images are clickable, try navigating using the images!

You can get the book here.1


How does an animal figure out mating and courtship? I doubt they have access to the internet or pick up artists. Nor do their friends show them a video to explain things.

The answer is fixed-action patterns. These are sequences of behaviour that occur in the same order every time. It’s as if the patterns were recorded on tapes within the animals. Click and the appropriate tape is activated; whirr and out rolls the standard sequence of behaviours.2

The most interesting thing about all this is the way the tapes are activated. The alpha male’s territorial defense tape whirrs whenever another male enters his territory. But there is a quirk in the system. It is not the rival male as a whole that is the trigger; it is some specific feature of him, the trigger feature.

For example, a mother turkey will accept any young turkey that goes “cheep-cheep”. It triggers her maternal instincts to feed and care for the baby turkey. However, if one of her own stops making the “cheep-cheep” sound, she either rejects them, or kills them. The funny thing is, researchers managed to get a stuffed pole cat - the natural predator - to get accepted by the mother-turkey by playing a “cheep-cheep” recording.

The automatic, fixed-action patterns of these animals work very well the great majority of the time. Because only healthy, normal turkey chicks make the peculiar sound of baby turkeys, it makes sense for mother turkeys to respond to that single “cheep-cheep” noise. “Natural” polecats don’t make that noise. By reacting to that one stimulus, the average mother turkey will almost always behave correctly.

It’s not just lower animals, but we, too, have our preprogrammed tapes. Although they usually work to our advantage, we can be duped into playing them at the wrong times. All it takes is figuring out the trigger.

“Because” is to us, what “cheep-cheep” is to the mother turkey. It triggers an automatic compliance response from people, even when they are given no subsequent reason to comply. “Can I cut in line in front of you to use the printer because I need to make some copies?”. Click, whirr!

As another example, looking for the “cheep-cheep” is exactly what we do with metrics in a company - we think if revenue is high or profits over earning ratio is over 25, then the company is good.

However, not even the best stereotypes and trigger features work every time. We accept their imperfection, since there is no other choice. Without them we would stand frozen, collecting all the information as the time for action speeds by.

With this machinery in mind, let’s dive into the six pieces of information, or proxy metrics we use to govern behaviour. For each principle, we’ll first look at the characteristics, then the optimal operating conditions, followed by how not to fall for them.

Principle #1: Reciprocation

The rule says that we should try to repay, in kind, what another person has provided us. If someone does us a favour, we should do one in return. We are obliged to the future repayment of gifts, favours and invitations.

This is one of the most powerful weapons of influence. In 1985, Ethiopia, one of the most impoverished countries, sent $5,000 in aid to Mexico. Ethiopia needed the money. Despite this, they sent the money because Mexico had sent aid to Ethiopia in 1935, when it was invaded by Italy. The need to reciprocate transcended great cultural differences, long distances, acute famine, and immediate self-interest. Obligation triumphed.

The Rule Is Overpowering

Strange, disliked, or unwelcome others can enhance the chance that we will comply with one of their requests, by first doing us a favour. Requests that would have been refused turn into a yes because of this existing feeling of indebtedness.

Consider an experiment performed by Professor Dennis Regan of Cornell University. Two subjects were asked to rate the quality of some paintings as part of an experiment on “art appreciation.” The second rater, Joe, was only posing as a subject and was actually Dr. Regan’s assistant.

In some cases, Joe did a small, unsolicited favour for the true subject. During a short rest period, he left the room for a couple of minutes and returned with two bottles of Coca-Cola, one for the subject and one for himself, saying, “I asked him [the experimenter] if I could get myself a Coke, and he said it was okay, so I bought one for you, too.” In other cases, Joe did not provide the subject with a favour; he simply returned from the two-minute break empty-handed. In all other respects Joe behaved identically.

Later on, after all the paintings had been rated and the experimenter had left the room, Joe asked the subject to do him a favour. He indicated that he was selling raffle tickets for a new car and that if he sold the most tickets, he would win a fifty-dollar prize. Joe’s request was for the subject to buy some raffle tickets at twenty-five cents apiece: “Any would help, the more the better.”

The major finding of the study concerns the number of tickets subjects purchased from Joe under the two conditions. Joe was more successful in selling his raffle tickets to the subjects who had received his earlier favour.

Dr. Regan also had the subject fill up a form indicating whether they liked Joe or not. As expected, people who liked Joe more, bought more tickets in the regular case (without coca-cola).

However, in the case of the Coca-Cola, liking didn’t matter. The subjects felt obligated to return the favour, and they did, even if they disliked Joe.

The rule for reciprocity was so strong that it overwhelmed the influence of liking.

The Rule Enforces Uninvited Debts

Another person can trigger a feeling of indebtedness by doing us an uninvited favour. It does not require us to have asked for what we have received in order to feel obligated to repay.

Joe had voluntarily left the room and returned with one Coke for himself and one for the subject. Not a single subject refused the Coke. Receipt of that Coke produced an indebtedness that manifested itself when Joe announced his desire to sell some raffle tickets.

There is an important asymmetry here — all the free choices were Joe’s. He chose the form of the initial favour, and he chose the form of the return favour. We could say that the subject had the choice of saying no to both of Joe’s offers, but those would have been tough choices. To have said no at either point would have required the subject to go against the natural cultural forces favouring reciprocation arrangements that Joe had aligned himself with.

In our culture, there is an obligation to give, receive, and repay. This obligation to receive makes it easy to exploit, as reciprocity kicks in once we have received.

It does not require us to have asked for what we have received in order to feel obligated to repay.

The Rule Can Trigger Unfair Exchanges

The rule developed to promote equal exchanges between partners, yet it can be used to bring about unequal results. The average subject who had been given a ten-cent Coca-Cola bought two of Joe’s raffle tickets, although some bought as many as seven. Joe made quite a deal.3

Most of us find it disagreeable to be in a state of obligation, which drives us to return favours that might be much larger than the initial one - just to get rid of the feeling.

Further, there is a genuine distaste for individuals who fail to conform to the dictates of the reciprocity rule. People who don’t return favours are disliked by society.

Reciprocal Concessions

Another consequence of the rule is an obligation to make a concession to someone who has made a concession to us.

The Girl Scout selling a box of cookies at your door? Her request that you purchase one-dollar chocolate bars, if not the five-dollar cookie box is a form of concession on her part. When presented as a retreat from the original request of the cookie box, we feel obligated to respond in kind by buying the chocolate bar.

Of course, the tendency to reciprocate a concession is not so strong that it will invariably work in all instances on all people. None of the weapons of influence is that strong.

The second request does not have to be small, it only has to be smaller than the initial one. The critical thing about a requester’s retreat from a larger to a smaller favour is its appearance as a concession.

However, if the first set of demands is so extreme that it’s seen as unreasonable, the tactic backfires. The gifted negotiator, then, is one whose initial position is exaggerated enough to allow for a series of reciprocal concessions that will yield a desirable final offer from the opponent, yet is not so outlandish as to be seen as illegitimate from the start.

“Grant Tinker and Gary Marshall are masters of this art in their negotiations with network censors. In a candid interview with TV Guide writer Dick Russell, both admitted to “deliberately inserting lines into scripts that a censor’s sure to axe” so that they could then retreat to the lines they really wanted included.”

There are also positive by-products of the act of concession: feelings of greater responsibility for, and satisfaction with, the arrangement. It is this set of sweet side effects that enables the technique to move its victims to fulfill their agreements and to engage in further such agreements.

The requester’s concession within the technique not only causes targets to say yes more often, it also causes them to feel more responsible for having “dictated” the final agreement. Further, an agreement that has been forged through the concessions of one’s opponent is quite satisfying.

Saying No

We will always encounter generous individuals as well as many people who try to play fairly by the reciprocity rule rather than to exploit it. They will doubtless become insulted by someone who consistently rejects their efforts; social friction and isolation could well result. A policy of blanket rejection, then, seems ill advised.

Thus, accepting first favours for what they are seems reasonable. However, if the initial favour turns out to be a device, a trick, an artifice designed specifically to stimulate our compliance with a larger return favour, that is a different story. Here our partner is not a benefactor but a profiteer. And it is here that we should respond to his action on those terms. Once we have determined that his initial offer was not a favour but a compliance tactic, we need only react to it accordingly to be free of its influence.

The rule says that favours are to be met with favours; it does not require that tricks be met with favours.

Principle #2: Commitment and Consistency

It is easier to resist at the beginning than at the end. — Leonardo da Vinci

Consider the racetrack experiment. Thirty seconds before putting down their money, bettors were tentative and uncertain; thirty seconds after the deed, they were more optimistic and self-assured. Once a stand had been taken, the need for consistency pressured these people to bring what they felt and believed into line with what they had already done. They convinced themselves that they had made the right choice and, no doubt, felt better about it all.

This automatic consistency is a difficult reaction to curb. It offers us a way to evade the rigors of continuing thought. And as Sir Joshua Reynolds noted, “There is no expedient to which a man will not resort to avoid the real labor of thinking.” With our consistency tapes operating, we can go about our business, excused from the toil of thinking too much.

Sometimes it is not the effort of hard, cognitive work that makes us shirk thoughtful activity, but the harsh consequences of that activity. There are certain disturbing things we would rather not realize. Automatic consistency can supply a safe hiding place from those troubling realizations.

Robert Cialdini attended a transcendental meditation (TM) program designed to recruit new members, promising one to achieve all kinds of things. The presenters explained the logic behind TM, followed by questions. The question section was where Cialdini demolished their arguments - the presenters couldn’t recover.4 However, at the end, aspiring actors wanting to get big, insomniacs looking for a way to fall asleep, students failing college looking for a way to survive on less sleep - all were promised a solution and rushed to put in the downpayment. Puzzled, Cialdini asked them if his arguments made sense. The college student responded, “Well, I wasn’t going to put down any money tonight because I’m really quite broke right now; I was going to wait until the next meeting. But when you started talking, I knew I’d better give them my money now, or I’d go home and start thinking about what you said and never sign up.”

There is no expedient to which a man will not resort to avoid the real labor of thinking.

What puts this automatic consistency into action? Researchers think it’s commitment. Once a stand is taken, there is a natural tendency to behave in ways that are consistent with the stand.

Consider the marketing plan by toystores. They start prior to Christmas with attractive TV ads for certain special toys. The kids want what they see and extract Christmas promises for these items from their parents. Now here’s where the genius of the companies’ plan comes in: They undersupply the stores with the toys they’ve gotten the parents to promise. Most parents find those things sold out and are forced to substitute other toys of equal value. The toy manufacturers, of course, make a point of supplying the stores with plenty of these substitutes. Then, after Christmas, the companies start running the ads again for the other, special toys. Sure enough, a promise had been made, so it’s time to fulfill it.

Since commitments are the real enforcers of consistency, let’s look at commitment tactics used in the wild.

The Action

Our best evidence of what people feel and believe comes less from their words and more from their deeds. Observers trying to decide what someone is like look closely at their actions. What’s surprising is that people use this same evidence to decide what they are like. Their behaviour tells them what they are like. It is a primary source of information about their beliefs, values, and attitudes.

The mere knowledge that someone viewed them as charitable caused housewives being asked for donations to donate more to charity.

This gives written statements immense committing power.

Consider the Chinese prison camps during the Korean War. Writing was one sort of confirming action that the Chinese urged upon the men. It was never enough for the prisoners to listen quietly or even to agree verbally with the Chinese line; they were always pushed to write it down as well.

A written testament can be shown to other people, which means it can be used to persuade those people. It can persuade them to change their own attitudes in the direction of the statement. But more important for commitment, it can persuade them that the author believes what was written. People have a natural tendency to think that a statement reflects the true attitude of the person who made it. What is surprising is that they continue to think so even when they know that the person did not freely choose to make the statement.

Before long, the Chinese knew, these actions would begin to take their toll, causing the men to change their views of themselves to align with what they had done.

The Public Eye

Public commitments tend to be lasting commitments.

The Chinese arranged to have the pro-Communist statements of their captives seen by others. A man who had written a political essay the Chinese liked, for example, might find copies of it posted around camp, or might be asked to read it to a prisoner discussion group, or even to read it on the camp radio broadcast.

To explore public commitments, Deutsch and Gerard set up a college student experiment. Students were asked to guess the number of lines in a passage they were shown. Some students were asked to commit publicly (write and show your estimates), others privately (write it down and erase it), and some others not at all (just think about it).

Then, they were given evidence that suggested their estimates were wrong. Compared to the uncommitted students, those who had written their decisions for a moment were less willing to change their minds when given the chance. Writing down their first judgments caused them to resist the influence of contradictory new data and stuck to their previous choices.

But Deutsch and Gerard found that, by far, it was the students who had publicly recorded their initial positions who most resolutely refused to shift from those positions later. Public commitment had hardened them into the most stubborn of all.

The Effort Extra

Yet another reason that written commitments are so effective is that they require more work than verbal ones.

A pair of young researchers, Elliot Aronson and Judson Mills, tested their observation that “persons who go through a great deal of trouble or pain to attain something tend to value it more highly than persons who attain the same thing with a minimum of effort.”

They found that college women who had to endure an embarrassing initiation ceremony to gain access to a sex discussion group convinced themselves that their new group and its discussions were extremely valuable, even though Aronson and Mills had previously rehearsed the other group members to be as “worthless and uninteresting” as possible.

This is also why initiation-hazing in fraternities runs rampant. It ensures that new members value and stick by the fraternity.

The inner choice

Back to the Chinese Prison Camp, the Chinese wanted as many Americans as possible to enter their pro-Communism essay writing contests so that, in the process, they might write things favourable to the Communist view. If, however, the idea was to attract large numbers of entrants, why were the prizes so small? A few extra cigarettes or a little fresh fruit were often all that a contest winner could expect.

They wanted the men to own what they had done. No excuses, no ways out. A prisoner who salted his political essay with a few anti-American comments could not be permitted to shrug it off as motivated by a big reward. It was not enough to wring commitments out of their men; those men had to take inner responsibility for their actions.

Social scientists have determined that we accept inner responsibility for a behavior when we think we have chosen to perform it in the absence of strong outside pressures. A large reward is one such external pressure. It may get us to perform a certain action, but it won’t get us to accept inner responsibility for the act. Consequently, we won’t feel committed to it. The same is true of a strong threat; it may motivate immediate compliance, but it is unlikely to produce long-term commitment.

All this has important implications for rearing children. It suggests that we should never bribe or threaten our children to do the things we want them to believe in. Such pressures will probably produce temporary compliance with our wishes. However, if we want more than just that, if we want the children to believe in the correctness of what they have done, then we must arrange for them to accept inner responsibility for the actions we want them to take.

The important thing is to use a reason that will initially produce the desired behavior and will allow a child to take personal responsibility for that behavior.

Saying No

“Foolish consistency is the hobgoblin of little minds” - Ralph Waldo Emerson

Cialdini on listening to your gut about things you don’t want to say yes to, but do:

I listen to my stomach these days. And I have discovered a way to handle people who try to use the consistency principle on me. I just tell them exactly what they are doing. It works beautifully.

“So I’m not interested in your entertainment club because of what Emerson said about foolish consistency and hobgoblins of the mind.”
Stunning Young Woman (staring blankly): Huh?
Look. What I told you during your fake survey doesn’t matter. I refuse to allow myself to be locked into a mechanical sequence of commitment and consistency when I know it’s wrongheaded. No click, whirr for me.

Another way to avoid foolish consistency is to compare current information to the information you had when you made a decision.

“Knowing what I know about the real price of this gasoline, if I could go back in time, would I make the same choice again?” Concentrating on the first burst of impression I sensed, the answer was clear: No.

Principle #3: Social Proof

Convince and ye shall be convinced!

When we are unsure of ourselves, when the situation is unclear or ambiguous, or when uncertainty reigns, we are most likely to look to and accept the actions of others as correct.

Consider an emergency: there has been a car crash. Several bystanders are present.

A bystander to an emergency would be unlikely to help when there are a number of other bystanders present. The first reason is that with several potential helpers around, the personal responsibility of each individual is reduced: “Perhaps someone else will give or call for aid, perhaps someone else already has.” So with everyone thinking that someone else will help or has helped, no one does.

The second reason is the pluralistic ignorance effect. Very often an emergency is not obviously an emergency. Is the man lying in the alley a heart-attack victim or a drunk sleeping one off? Are the sharp sounds from the street gunshots or truck backfires? Is the commotion next door an assault requiring the police or an especially loud marital spat where intervention would be inappropriate and unwelcome? What is going on? In times of such uncertainty, the natural tendency is to look around at the actions of others for clues. We can learn from the way the other witnesses are reacting, whether the event is an emergency or not.

As a victim, then, you must do more than alert bystanders to your need for emergency assistance; you must also remove their uncertainties about how that assistance should be provided and who should provide it.

There is another important working condition: similarity. The principle of social proof operates most powerfully when we are observing the behavior of people just like us.

People like us do things like this - Seth Godin

We will use the actions of others to decide on proper behavior for ourselves, especially when we view those others as similar to ourselves.

This is why I find “13 Reasons Why” so sinister too. In a morbid illustration of the principle of social proof, at-risk people decide how they should act on the basis of how some other troubled person has acted.

This effect has been observed so much that it now has a name. Werther effect: immediately following a front-page suicide story the suicide rate increases dramatically in those geographical areas where the story has been highly publicized.

Dr. David Phillips from the University of San Diego demonstrated using the Werther Effect that the odds for survival when we travel change measurably for a time following the publication of certain kinds of front-page suicide stories.

There are several examples that affect you and me too. Consider cars on a highway, and a peculiar kind of accident. Events leading to the accident would start when a pair of cars, one behind the other, would simultaneously begin signalling an intention to get out of the lane they were in and into the next. Within seconds, a long line of drivers to the rear of the first two would follow suit, thinking that something—a stalled car or a construction barrier—was blocking the lane ahead. It would be in this crush to cram into the available spaces of the next lane that a collision frequently happened. Very often, there would be no obstruction to be avoided in the first place.

This provides certain insights into the way we respond to social proof. First, we seem to assume that if a lot of people are doing the same thing, they must know something we don’t. Especially when we are uncertain, we are willing to place an enormous amount of trust in the collective knowledge of the crowd. Second, quite frequently the crowd is mistaken because they are not acting on the basis of any superior information but are reacting, themselves, to the principle of social proof.

In a similar situation, a few decades ago, the Red Indians realized it was possible to kill a tremendou number of buffalo by starting a herd running towards a cliff. The animals, responding to the thundering social proof around them—and never looking up to see what lay ahead—did the rest.

Saying No

On the whole, social proof provides valuable information on how to act. It’s like an autopilot: It works great and takes us where we want to be, as long as the sensors work and feed in the correct information. However, with incorrect information, like a sensor telling the autopilot we are 10,000 m above sea level, while in fact we are 100 m above sea level, we are sure to crash and burn.

Then, our best defense against these disadvantages is to recognize when the data is in error. If we can become sensitive to situations where the social-proof automatic pilot is working with inaccurate information, we can disengage the mechanism and grasp the controls when we need to.

First of these situations is when social evidence is falsified by design. For example, the canned laughter in comedy shows telling you when to laugh.

Second of these situations is when an innocent, natural error produces a snowball effect. Remember the cars on the highway that wanted to switch lanes for no apparent reason?

Principle #4: Liking

What makes us like someone? Social scientists have been investigating this question for decades. This is their accumulated wisdom.


There seems to be a click, whirr response to attractive people. Like all click, whirr reactions, it happens without forethought. The response itself falls into a category that social scientists call “halo effects.” A halo effect occurs when one positive characteristic of a person dominates the way that person is viewed by others. And the evidence is now clear that physical attractiveness is often such a characteristic.


We like people who are similar to us. This fact seems to hold true whether the similarity is in the area of opinions, personality traits, background, or life-style. Consequently, those who wish to be liked can accomplish this by appearing similar to us.


The information that someone fancies us can be a bewitchingly effective device for producing return liking and willing compliance


Often we don’t realize that our attitude toward something has been influenced by the number of times we have been exposed to it in the past.


Consider this boy scout experiment by Muzafer Sherif. They first divided the boys into two groups designed to create hostility. Separating the boys into two residence cabins was enough to stimulate a “we vs. they” feeling between the groups; and assigning names to the two groups (the Eagles and the Rattlers) accelerated the sense of rivalry.

A more challenging issue then faced the experimenters: how to remove the entrenched hostility they had created. They first tried the contact approach of bringing the bands together more often. But even when the joint activities were pleasant ones, such as movies and social events, the results were disastrous. Picnics produced food fights, movies produced shouting contests.

The answer was cooperation, not competition.

On a daylong outing, the single truck available to go into town for food was “found” to be stuck. All the boys pulled and pushed together until the vehicle was on its way. In another circumstance requiring cooperation, the campers were informed that a desirable movie was available for rental but that the camp could not afford it. Aware that the only solution was to combine resources, the boys rented the film with pooled money and spent an unusually congenial evening enjoying it together.

Conjoint efforts toward common goals steadily bridged the rift between the groups. Before long, the verbal baiting had died, the jostling in lines had ended, and the boys had begun to intermix at the meal tables.

This is why battling climate change is hard, too. There’s no common enemy, which makes groups fight against each other, instead of uniting to fix the cause.

The crucial procedure was the experimenters’ imposition of common goals on the groups. It was the cooperation required to achieve these goals that finally allowed the rival group members to experience one another as reasonable fellows, valued helpers, and friends.

However, there is a caveat.

Although the familiarity produced by contact usually leads to greater liking, the opposite occurs if the contact carries distasteful experiences with it. Therefore, when children of different racial groups are thrown into the incessant, harsh competition of the standard American classroom, we ought to see—and we do see—the worsening of hostilities.

Conditioning and Association

There is a natural human tendency to dislike a person who brings us unpleasant information, even when that person did not cause the bad news. The simple association with it is enough to stimulate our dislike.

Shakespeare captured the essence of it with one vivid line. “The nature of bad news infects the teller.”

An innocent association with either bad things or good things will influence how people feel about us.

For example, using the “luncheon technique,” Gregory Rarzan found that his subjects became fonder of the people and things they experienced while they were eating.

Razran’s insight was that there are many normal responses to food besides salivation, one of them being a good and favourable feeling. Therefore, it is possible to attach this pleasant feeling to anything that is closely associated with good food.

All kinds of desirable things can substitute for food in lending their likable qualities. That is why those good-looking models are standing around in the magazine ads. And that is why radio programmers are instructed to insert the station’s call-letters jingle immediately before a big hit song is played.

In other cases, people actively try to associate themselves with a positive subject.

A lot of strange behavior can be explained by the fact that people understand the association principle well enough to strive to link themselves to positive events and separate themselves from negative events—even when they have not caused the events.

“All things being equal, you root for your own sex, your own culture, your own locality…and what you want to prove is that you are better than the other person. Whomever you root for represents you; and when he wins, you win. - Isaac Asimov”

On the flip side, when we don’t look so good, we disassociate to salvage prestige.

It is not when we have a strong feeling of recognized personal accomplishment that we will seek to bask in reflected glory. Instead, it will be when prestige (both public and private) is low that we will be intent upon using the successes of associated others to help restore image.

Saying No

You just met Dan. Here’s a question to ask yourself: “In the 25 minutes I’ve known Dan, have I come to like him more than I would have expected?”

If the answer is yes, we might want to reflect upon whether Dan behaved during those few minutes in ways that we know affect liking. We might recall that he had fed us coffee and doughnuts before launching into his pitch, that he had complimented us on our choice of options and color combinations, that he had made us laugh, that he had cooperated with us against the sales manager to get us a better deal.

Principle #5: Authority

Early on, parents and teachers knew more than we did, and taking their advice proved beneficial—partly because of their greater wisdom and partly because they controlled our rewards and punishments. As adults, the same benefits persist for the same reasons, though the authority figures now appear as employers, judges, and government leaders.

Once we realize that obedience to authority is mostly rewarding, it is easy to allow ourselves the convenience of automatic obedience. The simultaneous blessing and bane of such blind obedience is its mechanical character. We don’t have to think; therefore, we don’t.

This paradox is the same one that attends all major weapons of influence.

Why on earth would we take Robert Young’s word for the health consequences of decaffeinated coffee? Because he is associated in the minds of the American public with Marcus Welby, M.D., the role he played in an earlier long-running television series.5

The appearance of authority is enough. This tells us something important about reactions to authority figures. When in a click, whirr mode, we are vulnerable to both, the symbols of authority, and the substance.

Titles, clothes, and accessories

These are the three main symbols of authority.

With each increase in status, the same man grew in perceived height by an average of a half inch, so that as the “professor” he was seen as two and a half inches taller than as the “student”.

There’s an interesting connection between status and perceived size. In judging the size of coins, for example, children most overestimate the size of the more valuable coins. Adults are just as guilty of this, too.

It is not necessarily the pleasantness of a thing that makes it seem bigger to us, it is its importance. So, both, extremely negative, and extremely positive symbols seem bigger than they are.

Since size and status are related, it’s possible for someone to benefit by substituting one for the other.

The outward signs of power and authority may be counterfeited with the flimsiest of materials - a uniform, calling yourself a “Senior Inspector”, or maybe just carrying around a stethoscope.

Motorists would wait significantly longer before honking their horns at a new, luxury car stopped in front of a green traffic light than at an older, economy model.

If you thought you’d honk quickly at the luxury car after reading that, so did lots of other students. People underestimated the authority influence when asked about what they’d do in such a situation.

Not only does this influence work forcefully on us, it does so unexpectedly.

Saying No

Posing two questions to ourselves can help discern when to listen to authority.

The first is to ask, “Is this authority an expert?”

If no, we’re done. An actor playing the role of a doctor isn’t an expert at passing real medical advice.

Suppose, though, we are confronted with an authority we determine is a relevant expert. Before submitting to authority influence, it would be wise to ask a second simple question: “How truthful can we expect the expert to be here?”

This is also Charlie Munger’s number 1 principle: Show me the incentives, I’ll show you the outcome.

When asking ourselves about such a person’s trustworthiness, we should keep in mind a little tactic compliance practitioners often use to assure us of their sincerity: They will seem to argue to a degree against their own interests. By establishing their basic truthfulness on minor issues, the compliance professionals who use this ploy can then be more believable when stressing the important aspects of their argument.

For example, consider a waiter passing on information about a dish not being great today, and suggesting something cheaper instead. Everyone feels grateful, and consequently the rule for reciprocity would work in his favour when the time comes to decide on his gratuity.

Principle #6: Scarcity

Something that held little appeal for me had become more attractive merely because it would soon become unavailable.

That’s all there is to scarcity.

Advertisements urging young women to check for breast cancer through self examination are more successful if they state their case in terms of what stands to be lost (e.g., “You can lose several potential health benefits by failing to spend only five minutes each month doing breast self-examination”) rather than gained (e.g., “You can gain several potential health benefits by spending only five minutes each month doing breast self-examination”).6

Phosphate detergents clean, whiten, and pour no better after they are banned than before. We just assume they do because we find that we desire them more.

Scarcity raises the possibility that clever individuals holding a weak or unpopular position can get us to agree with that position by having their message restricted. The irony is that for such people — members of fringe political groups, for example — the most effective strategy may not be to publicize their unpopular views, but to get those views officially censored and then to publicize the censorship.

Timeliness of scarcity

Participants in a consumer preference study were asked to taste and rate cookies. Some participants were first given a jar of ten cookies that was then replaced by a jar of two cookies. Others had a jar of two cookies from the beginning.

Thus, before taking a bite, certain of the participants saw their abundant supply of cookies reduced to a scarce supply. Other participants, however, knew only scarcity of supply from the outset, since the number of cookies in their jars were left at two.

With this procedure, the researchers were seeking to answer a question about types of scarcity: Do we value things that have just become scarce more than things that have always been scarce? In the cookie experiment, the answer was plain. The drop from abundance to scarcity produced a more positive reaction to the cookies than the constant scarcity.

The idea that newly experienced scarcity is the more powerful kind applies to situations well beyond the bounds of the cookie study. For example, social scientists have determined that such scarcity is a primary cause of political turmoil and violence. People and communities who’ve been granted freedom lash out when someone tries to take it away.

The lesson applies as well to the politics of family as country. The parent who grants privileges or enforces rules erratically invites rebelliousness by unwittingly establishing freedoms for the child.

The cookies made less available through social demand were rated the most desirable of any in the study. This finding highlights the importance of competition in the pursuit of limited resources. Not only do we want the same item more when it is scarce, we want it most when we are in competition for it.

As a general rule, whenever the dust settles and we find losers looking and speaking like winners, and winners wondering what a mess they’ve made, we should be especially wary of the conditions that kicked up the dust— usually, open competition for a scarce resource. This shows up frequently in auctions with winners spending way more than they intended to.

Saying No

In the previous study, even though the scarce cookies were rated as significantly more desirable, they were not rated as any better-tasting than the abundant cookies. People were willing to pay more for a cookie that tastes no better. Therein lies an important insight. The joy is not in experiencing a scarce commodity but in possessing it. It is important that we not confuse the two.

As soon as we feel the tide of emotional arousal that flows from scarcity, we should use that feeling as a signal to stop short. Panicky, feverish reactions have no place in wise compliance decisions. We need to calm ourselves and regain a rational perspective.

Once that is done, we can move to the second stage by asking ourselves why we want the item under consideration. If the answer is that we want it for the purpose of owning it, then we should use its availability to help gauge how much we want to spend for it. However, if the answer is that we want it for its function (that is, we want something good to drive, drink, eat, etc.), then we must remember that the item under consideration will function equally well whether scarce or plentiful. We need to recall that the scarce cookies didn’t taste any better.


Very often in making a decision about someone or something, we don’t use all the relevant available information. Instead, we use only a single, highly representative piece of the total. And an isolated piece of information can lead us to stupid mistakes. These mistakes, when exploited by clever others, leave us looking silly or worse.

Despite this flaw, the pace of modern life demands that we frequently use this shortcut.7 These single pieces of the whole are the most popular prompts because they are the most reliable ones. Usually, they point us toward the correct choice. That is why we employ the factors of reciprocation, consistency, social proof, liking, authority, and scarcity so often and so automatically in making our compliance decisions. Each, by itself, provides a highly reliable cue about when we will be better off saying yes than no.

Get the book here.8

  1. Affiliate link 

  2. For people born after the 90s, this is how a tape recorder plays a casette: Click, Whirr 

  3. Dr. Cialdini claims it holds for much greater amounts, too. 

  4. In the book, it’s the logician friend and not Cialdini that points out the mistakes. But, for the purpose of the blog post, introducing a new character didn’t make sense here. 

  5. A more recent example is Hugh Laurie as House M.D. 

  6. Meyerwitz and Chaiken (1987) in New York City. 

  7. System 1, as Daniel Kahneman put it. 

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