Influence by Robert Cialdini

Reading Time: 5 minutes

Influence, as the title suggests, is a book about the psychology of persuasion. Beautifully written and easy to read, Caldini explains why humans behave the way we do when buying products or services, and what influences us to make those decisions.

The book is broken down into six universal principles called the Weapons of Influence, as follows:

  • Reciprocation
  • Commitment and Consistency
  • Social Proof
  • Liking
  • Authority
  • Scarcity

Reciprocation is the rule of give and take. If you give something to somebody, they are far more likely to reciprocate and return something. Not only that, but studies also show that the reciprocation is often far greater than the initial giving. The example often cited in the book is the Hare Krishnas strategy during the 1970’s and 80’s, where Krishna members were often seen in their colorful clothing in American airports asking for donations towards their society. Anybody who has watched the Airplane movies may have a slightly twisted memory of these events, although it’s a good way to picture how it worked.

Initially, members simply asked for donations towards their society with very little success. But when they changed strategy by giving a small gift to an arriving passenger in the form of a book or flowers pressed into the hand as a “gift for you sir”, the success ratio for donations increased massively. Even when the gift was not wanted, the power of the reciprocation rule was enough for a majority of targets to eventually fish into their pockets for a dollar or two.

This is a highly successful and influential practice even when the target customer is fully aware of what is happening. The power of this rule rightly puts it at number one in the weapons of influence, and is something which can be applied across any industry, product or service.

Commitment and Consistency is a weapon playing on our natural human instinct to stick with decisions and not veer from the choices we have made. This is very much an automated thought process which allows us to make quick and easy decisions within this modern day society, where we are bombarded with information on a regular basis. If we don’t have to change our minds, or reconsider the decisions we have just made, it is easy for us to simply stick with our original decision.

My favorite example cited plays on commitments we have made as a parent to our children when it comes to Christmas presents. If you’ve ever gone into a toy shop before Christmas to buy your child the current “must-have” toy of the year, only to discover it is not in stock, you will have found yourself trapped by this weapon. I used to think this was due to a poor supply chain. Now I understand this is part of the shop’s strategy to increase sales.

As a parent, you cannot leave the shop empty handed with no present for little Johnny, so you are forced to buy something else. When Christmas comes, Johnny is excited to open his presents. Being a good boy he smiles and doesn’t want to be ungrateful, but you can still feel his sadness because you didn’t buy him what he really wanted. You have committed to your child to buy that toy, but you have let him down at Christmas. So with the rule of consistency and commitment, you stroll back into the shop in January to discover that the toy is now in stock, which you purchase, therefore doubling the sale with the shop.

Another technique within this rule is used by telephone solicitors drumming up donations for charity. The first question they ask is always something like “how are you doing today?”, to which most replies are “good, great” etc. Once that question has been answered positively, the caller continues saying “it’s really good to know you are doing great today, as we are looking to help less fortunate (insert charity) with donations towards their own happiness and well-being”. 

By simply beginning with a question about the target’s state of mind, if they have answered positively, they are now trapped and feel obliged to agree to the donation request. Once a commitment has been made, the consistency of human nature makes this extremely difficult to reverse psychologically.

Social Proof is the principle of group think. Where all think alike, no one thinks very much. If everybody is doing something, or nothing, then that is the easiest and most natural path to follow. This chapter introduced me to a terminology previously unknown; pluralistic ignorance. This is the phenomenon where entire groups of normally good and caring people fail to aid victims in need of assistance.

The best example of this is shown through social experiments. Somebody will lay on the ground in a busy street where hundreds of people will walk past without paying attention to the possibly hurt person, simply because they see others walking past also. They follow “social proof”, and consider this reprieves them from any responsibility towards the possibly injured or hurt person.

An example of social proof from Hong Kong’s streets is the one where people join a queue, simply because there is a queue. The theory being; if people are queuing for something, there must be a good bargain at the end of it. This practice has often been used by nightclub owners, who keep queues longer than necessary outside their venues in the early hours, to make passers-by believe the club is highly popular and sought after. 

Liking is probably the easiest weapon of influence to relate to. It would not surprise anybody to know there is more chance of sales being made if you are liked by the target customer. Research shows we equate goodness, honesty and intelligence to people we are attracted to. It’s scary to think something so simple, can automatically make us believe somebody is good. 

Advertisers apply this weapon regularly while trying to sell products. Scantily clad models standing next to the latest car drinking their favourite beverage as an example. Taking this strategy further is having the latest pop or movie stars put their names next to a brand with advertisers hoping to prey on the gullibility of the public to follow their heroes, and buy whatever it is they have put their name against. An extremely effective method, which is why companies are prepared to pay big money to get such endorsements.

Authority is directed deference, where you follow somebody’s instructions simply because they have a higher social authority than you, such as a doctor or policeman, no matter how sensible or crazy those instructions might be. 

The Milgram Study is the most famous and relevant study conducted into this behavioural pattern. If you don’t know what that is, I won’t spoil it for you. It’s truly fascinating, and highlights how easily led we are simply because somebody has a (perceived) higher authority or knowledge than yourself.

Scarcity is the rule of the few, where simply by knowing there is a limited amount of something means you need to have it, and will often go great lengths to make it happen.

If you have watched The Wolf of Wall Street, you will have seen the boiler room escapades of money traders selling highly limited stocks to potential investors. The investments are always in limited supply, need to be bought within a short period of time before the chance disappears, and are sold with a very high return potential. This is the scarcity rule in full flow, which is also applied along with liking as the sales person is always extremely friendly. The final nail would be if they can get you to commit, because once you have committed your consistent human nature will take you along for the ride, until it’s too late and you discover you’ve been sold valueless stocks.

Anything which is scarce has a higher value and is very often indeed true. A rare stamp or football program will attract a far higher price than one in abundance. Watch out for the swindlers who play the scarcity rule to their advantage by point-blank lying.


All in all, I consider this a very important book to read for anybody who wants to increase their sales potential. If these weapons of influence are applied honestly and genuinely they can be very powerful. Naturally there are some people who exploit this knowledge to cheat and swindle, but that is not the idea for us. Most people are decent and want to be able to look at themselves in the mirror everyday and sleep peacefully at night. That being said, the type of people who use these weapons unscrupulously probably don’t have a conscience anyway so could go without sleep.

For most of us who are good and decent, these weapons of influence can be used to help others achieve happier, healthier and longer lives.

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