The street traders in Dublin’s Moore Street probably never heard of Dr. Robert Cialdini.


However they were very successfully using one of the universal principles of persuasion long before Dr. Cialdini ever published his seminal book, “Influence-The Psychology of Persuasion”.


Widely regarded as one of the most powerful and informative books about marketing written in the last 3 decades “Influence-The Psychology of Persuasion” has influenced every well informed attempt to persuade peoples’ behaviour.



Dr. Cialdini, a university professor in the University of Arizona, describes in his seminal work “Influence-the Psychology of Persuasion” how there are 7 fundamental psychological principles which influence people to say “yes”. In great depth he describes how successful salespeople and companies use most or all of these principles on a daily basis to persuade us to buy.


The 7 Principles of Persuasion

The 7 universal principles of persuasion are

  1. Material self interest
  2. Reciprocation
  3. Commitment and consistency
  4. Social proof
  5. Liking
  6. Authority
  7. Scarcity.


Number 1 above is self evident and does not require any detailed explanation.




The rule for reciprocation is one of the most powerful factors at force in the attempt to persuade.


Giving somebody something for free creates a powerful feeling of obligation in the recipient.


It can be very difficult to say no and it is this feeling of obligation that leaves us exposed in attempting to resist a good sales pitch.


Commitment and consistency


We as humans have a strong desire to be and to appear to be consistent. This is why salespeople will always attempt to ask you a series of questions which elicit a “yes” response in the early stages of their pitch.


The key to the salesperson getting you on a path of his choosing is if he can get you to make a commitment at the outset; the desire to be consistent will take care of the rest.


The desire to be consistent often pushes us along a path that we know to be wrong but which we cannot depart from such is the power of the desire to appear consistent and which has been recognized by prominent psychologists such as Newcomb and Fritz Heider.


Social Proof


Most of us assume that a course of action is more likely to be correct if other people are taking the same course of action.


Much as we all hate canned laughter on many tv programmes, tv studios still employ canned laughter because it is simply effective and works.




If the salesperson can get you to like him, he has a great chance of making a sale because we buy stuff from people we like.


The Tupperware party is a good example of the power at work here and the hostess ends up selling a lot of stuff to her friends, not because here friends want Tupperware storage containers but because they like the hostess.


She invited them to her home didn’t she?




“Follow an expert”-Virgil


We are influenced strongly by authority and expertise and who can resist the trappings of authority such as titles, nice clothes, nice cars, academic qualifications, uniforms and so on.


Authority is a huge factor in the ability to persuade and lead.




Moore Street traders or the guys at GAA or soccer matches shouting “get the last of the red apples/choc ices/bananas” knew all about the power of scarcity (or perception of scarcity) influencing sales.


These powerful and universal principles of persuasion should be at work in your marketing efforts for your business.


One of the easiest and most effective ways to wield these weapons of influence in your drive for new business is on a well structured website through the medium of content marketing..