If you can get someone to mentally commit to a product or a decision, he is likely to remain committed even after the terms and conditions change. This is why when stores, for example, advertise very low prices on a television set, they include in small print, "Quantities Limited." By the time you get to the store, all the bargain televisions are sold, but you are mentally committed to buying a new TV. Luckily for you, there are more expensive models available. So, you go home having spent $300 more on a television set than you originally planned, just because you needed to maintain a consistency between your desire for a new TV and your action of being in the store.
This tactic is also often used when goods and products go on sale. For example, a customer may be lured to a store by an incredible deal on a pair of nice dress shoes. Upon inquiring, the disappointed customer learns from the salesperson that her size is not in stock. Just as the customer is about to leave, the salesperson miraculously displays another strikingly similar pair--but this pair is not on sale.
Think of a time when you purchased a new car. Have you ever noticed that when you're about to sign the contract the price is $200 more than you expected? Well, someone conveniently forgot to tell you about the air conditioner or some other feature found in your car. You pay the extra $200 anyway because you're mentally committed to that car, and you don't want to go through the whole hassle and headache of trying to renegotiate the deal.
Often car dealers promise an incredible price, even a few hundred dollars below a competitor's price, all the while knowing it's not actually going to go through. The deal is offered only to motivate the buyer to purchase from their dealership. Once the customer decides to buy, the dealer sets up several conditions, each of them causing the customer to feel increasingly committed before finding out the real price: lengthy forms are filled out, great lengths are taken to set up specific financing terms, the customer is encouraged to take the car home and drive it to work, to run errands, to cruise the neighborhood. The dealer knows that while the customer is out joy riding, she is thinking of all the many reasons their purchase is justified
These tactics are even used when high school students and their parents are narrowing down the colleges they should attend. Just like car dealers, colleges often give a low estimate on your costs, and it's not until after you've signed up and registered that you discover your actual costs.
