This is part of a series of information/stories delivered from the INCREDIBLE book,  “Influence: The Psychology of Persuasion” by Robert Cialdini.     If you work or live a life where you have to get people to do thing, Influence studies and explains the 6 most powerful forces to persuade people.  No other book has been recommended to me more, by people smarter than both of us.

In short, they are:

1) Reciprocation

2) Social proof

3) Commitment & Consistency

4) Liking: People prefer to say ” yes” to those they know

5) Authority

6) Scarcity

And they will be a game changer for you and your business.


There is a principle in human perception, the contrast principle, that affects the way we see the difference between two things that are presented one after another. Simply put, if the second item is fairly different from the first, we will tend to see it as more different than it actually is. So if we lift a light object first and then lift a heavy object, we will estimate the second object to be heavier than if we had lifted it without first trying the light one.

A nice demonstration of perceptual contrast is sometimes employed in psychophysics laboratories to introduce students to the principle firsthand. Each student takes a turn sitting in front of three pails of water—one cold, one at room temperature, and one hot. After placing one hand in the cold water and one in the hot water, the student is told to place both in the lukewarm water simultaneously.

Retail clothiers are a good example. Suppose a man enters a fashionable men’s store and says that he wants to buy a three-piece suit and a sweater. If you were the salesperson, which would you show him first to make him likely to spend the most money? Clothing stores instruct their sales personnel to sell the costly item first. Common sense might suggest the reverse: If a man has just spent a lot of money to purchase a suit, he may be reluctant to spend very much more on the purchase of a sweater. But the clothiers know better. They behave in accordance with what the contrast principle would suggest: Sell the suit first, because when it comes time to look at sweaters, even expensive ones, their prices will not seem as high in comparison. Contrary to the commonsense view, the evidence supports the contrast-principle prediction. As sales motivation analysts Whitney, Hubin, and Murphy state, “The interesting thing is that even when a man enters a clothing store with the express purpose of purchasing a suit, he will almost always pay more for whatever accessories he buys if he buys them after the suit purchase than before.”

It is much more profitable for salespeople to present the expensive item first, not only because to fail to do so will lose the influence of the contrast principle; to fail to do so will also cause the principle to work actively against them. Presenting an inexpensive product first and following it with an expensive one will cause the expensive item to seem even more costly as a result.