Influence — Summary

This book will teach you the six universal principles of persuasion, how to use them and how to defend yourself against them.

Nature is full of strange behavior. For example, turkeys care for their chicks only when they emit their distinctive “chep-chep” sound.
Scientists can exploit this simplistic drive of the mother turkey with a stuffed replica of a polecat. The polecat is the arch-enemy of turkeys, but as long as the replica emits the distinctive “chep” sound, the mother turkey takes care of it.

We often think that we are not susceptible to such simplistic triggers, but that’s not true. Even with our human intellect, we cannot possibly analyze everything we encounter. There are many tricks which professional people can play on us to influence our behavior, for example, to sell us something.

When dealing with the complexity of life, we have to learn to defend ourselves from such manipulators.

1. Reciprocation

The human need for reciprocity

Humans have a fundamental need to reciprocate when they receive a favor or gift. This principle is often used by individuals and organizations to manipulate people.

The Krishna organization, for example, gifted flowers to passersby to get them to make donations.

The best counter strategy to such attempts is learning to discriminate between genuine favors and manipulation tactics.


Rejection-then-retreat is one of the most powerful manipulative strategies because it combines two powerful principles, the contrast principle, and the reciprocation principle.

Imagine that something would offer you to buy a raffle for 5$, after rejecting he asks you to buy at least a 1$ sweet, you feel compelled to buy it despite not liking sweets.

You feel obliged to accept the second offer because you rejected the first one (reciprocation) furthermore the second one is much cheaper than the first one which adds weight to your feeling (contrast).

2. Scarcity

Scarcity creates desire

A powerful influence in decision making is scarcity. We tend to value something according to its availability. Advertisers widely use this principle through phrases like “Last chance!” and “Sale ends today.”

Studies showed that participants bought 3 times more when there was a time limit then when there were none.

Scarcity of information

In the study above, the effect of limited time could further be compounded when people were told that only a selected few knew about the sale. The combination of the scarcity of time and information, made shoppers buy 6 times more than unaware customers.

Scarcity and contrast

We tend to want something more when its availability has decreased recently rather than if it happened over time. That’s why revolutions tend to happen when living conditions deteriorate sharply rather than when they are consistently low.

Scarcity combined with contrast works so well because the feeling of abundance or availability is still fresh in people’s memory, which creates the contrast.

Scarcity and Competition

The thought of losing something to a rival is another powerful strategy. We tend to value something more if other people want it too. Popularity or demand defines value. This principle is often used by real estate agents.

They simply mention to potential buyers that several other bidders are also interested in a given house, this creates the scarcity-competition effect.

Banning something rises its value

People tend to want what they can’t have. This effect stems from the fact that humans hate to lose opportunities. We want options instead of limitations. This principle of scarcity can be created by banning something.

An example of this happened when Dade County in Florida declared laundry detergents containing phosphate to be illegal. Residents not only began smuggling the product, but they also started to see those detergents as better than before.

Another example can be observed when parents forbid their children to play with something. That object automatically becomes more attractive to them.

3. Authority

Authority inhibits independent thinking

Stanley Milgram demonstrated that volunteers would administer potentially lethal electrical shocks to others simply because they were told so by authority.

A nurse who got written instruction from a doctor to administer drops to a patient anus, even though the treatment was mean for his right ear.

We tend to obey authority without questioning it. People who get told something from authority don’t tend to think about it independently very much.

Con artists who don uniforms exploit this principle in order to appear as individuals of authority. When people don’t have evidence about another people’s authority, they tend to estimate through simple symbols. In Milgram’s experiment, for example, a white lab coat and a clipboard were enough to convince individuals to torture their fellow test subjects.

We can protect ourselves from authority figure abuse by asking two questions.

  • Is the person really an authority or just someone masquerading as one?
  • How honest can we expect this authority to be in the given situation?

4. Consistency

Committing to consistency or the Foot-in-the-door technique (FITD)

People tend to want consistency with things they committed to. For example, one study showed that only 20% of people reacted when a thief stole a radio from the neighboring towel. But when the owner of the towel first asked them to watch their things, 95% of them became vigilant and even chased the thief to recover the radio.

Of course, fear of consequences from the owner also may have played a role, but people seem to want to be consistent with what they say or the image they convey.

In the Korean War, Chinese interrogators made American prisoners write down little concessions such as “America is not perfect.”
Once they read those statements aloud in the prison camp, their compatriots labeled them as “collaborators.”

Once they were labeled as collaborators, they then became more helpful to the Chinese. They adjusted their self-image so that collaboration became consistent with it. Having those statements written on paper added more weight to them as something written words with a signature are harder to deny than just vocalizing something.

This approach of successive approximations is widely used by salesmen who often secure large purchases by getting customers first to agree on small commitments.

5. Consensus

Inner commitment is powerful

Whether in ancient African tribes or American fraternities, new members often have to pass through an initiation ritual which involves pain and degradation.

The reason for those rituals is that people tend to value more something when they have to go through some trouble to attain it. Members become more committed after passing through the effort.

Sometimes those initiation rituals take the form of community service, like changing bedpans at hospitals. The reason those rituals often involve some mildly disgusting things is that they want new members to make an inner choice solely for the reason to join, not for another external reason like having done something beneficial to the community. Doing something exclusively for a greater good would make them less likely to commit with the same level of decisiveness.

Salespeople use this principle to get the compliance of customers. The Low-ball trick is such a technique in which the initial price is set much lower than the intended selling price. Once the buyer tested the product, for example when he made a test drive with a new car, the price is then announced to have been too low due to an error. Customers tend to end up buying the item because they have already made a commitment.

In uncertainty situations, people look for social proof

People often seek for social proof. This simply means that we tend to watch what others are doing, for example in a certain situation.

This principle is used to manipulate us in commercials for example. Artificial laughter signals through social proof that now is the moment we are supposed to laugh since the fake crowd laughs.

Churches use the same principle when they put in some bills in the collection baskets before they reach them around so that it seems like everyone is making donations.

In uncertain situations, social proof can lead to disaster. One famous case happened in 1964 when a young woman named Kitty Genovese was stabbed to death in front of her apartment. The whole attack lasted over half an hour and 38 people were watching and listening from their apartments, without taking any action nor calling the police.

Bystander inaction happens mainly due to two reasons. First, when several people are involved, each individual feels less responsible. Second, the uncertainty of urban environment leads to people looking for social proof to make sure not to do something risky. In the Genovese case, the neighbors were peeking what others were doing and as they saw the others watching they thought inaction was the appropriate thing to do.

If you find yourself in a similar situation, you should single out a single individual from the group and request help directly from him. Doing so will make it more likely that the person does not first look for guidance and instead acts.

People tend to be influenced by social peers

Teenagers tend to be susceptible to the opinions of their peers. It turns out that this is something very common among humans. We tend to emulate people who are similar to ourselves.

Marketers exploit this tendency with fake interviews which were apparently made to random people on the street. They know that doing so will make people think that their product must indeed be good.

There is another, a more grim effect called the Werther effect. The Werther effect is named after the eighteen-century book that sparked a wave of suicides through Europe due to an apparent emulation of the protagonist.

Those emulations tend to happen to people similar to the protagonist. When a youngster committed suicide, youngsters start plowing their cars off bridges and embankments while older people react to suicides by other seniors.

There are dramatically more car and airplane crashes the week after a suicide is highly publicized in the media. After reading about the suicide, some people seem to emulate the victim. They often do so by making the deaths seem accidental, some of them crashing while driving or flying. Causing an unexplained increase in crashes.

Research has shown that any front page suicide story causes effectively 58 deaths of people who would otherwise continue on living.

6. Friendship / Liking

Our bias towards attractiveness and flattery

People tend to let their impression on someone or something influence their feelings and thoughts about that entity’s properties.
For example, people tend to like associate attractive people with positive character traits. They see attractive people as more smart, kind, and honest. This bias even has an effect on political elections.

We also tend to be suckers at flattery, for example when a salesperson compliments us about something.

The good cop/bad cop interrogation method makes use of the technique were one of the cops gives the appearance to be “on the same team.” First, the bad cop abuses the suspect verbally, then the good cop stands up for the suspect, playing the role of a confidante with the objective of eliciting a confession.

Associations are important for likeability

We tend to like people according to the things with which we associate them. Weathermen, for example, have gotten death threats for accurately predicting the weather.

In contrast, we tend to associate something with positive feelings if we happen to enjoy delicious food while hearing about it.

Whenever we like someone strongly in a short time, we should watch for manipulation techniques.

Get the book

Karl Niebuhr

Karl Niebuhr

I'm Karl! I like to read, learn and self-improve.
Karl Niebuhr

Latest posts by Karl Niebuhr (see all)

Also published on Medium.