The Contrast Principle
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. The contrast principle is well established in the field of psychophysics and applies to all sorts of perceptions besides weight. If we are talking to a beautiful woman at a cocktail party and are then joined by an unattractive one, the second woman will strike us as less attractive than she actually is.
In fact, studies done on the contrast principle at Arizona State and Montana State universities suggest that we may be less satisfied with the physical attractiveness of our own lovers because of the way the popular media bombard us with examples of unrealistically attractive models. In one study college students rated a picture of an average-looking member of the opposite sex as less attractive if they had first looked through the ads in some popular magazines. In another study, male college-dormitory residents rated the photo of a potential blind date. Those who did so while watching an episode of the Charlie’s Angels TV series viewed the blind date as a less attractive woman than those who rated her while watching a different show. Apparently it was the uncommon beauty of the Angels female stars that made the blind date seem less attractive.
A nice demonstration of the perceptual contrast is sometimes employed in psychopshyics 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 simulatanouesly. The look of amused bewilderment that immediately registers tells the story: Even though both hands are in the same bucket, the hand that has been in the cold water feels as if it is now in hot water, while the one that was in the hot water feels as if it is now in cold water. The point is that the same thing - in this instance room temperature water - can be made to seem very different, depending on the nature of the event that precedes it.
Be assured that the nice little weapon of influence provided by the contrast principle does not go unexploited The great advantage of this principle is not only that it works but also that it is virtually undetectable. Those who employ it can cash in on its influence without any appearance of having structured the situation in their favor. 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 the sweaters, even expensive ones, their prices will not seem as high in comparison. A man might balk at the idea of spending $95 for a sweater, but if he has just bought a $495 suit, a $95 sweater does not seem excessive. The same principle applies to a man who wishes to buy the accessories (shirt, belt, shoes) to go along with his new suit. 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 the 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 - hardly a desirable consequence for most sales organisations. So, just as it is possible to make the same bucket of water appear hotter or colder, depending on the temperature of previously presented water, it is possible to make the price of the same item seem higher or lower, depending on the price of a previously presented item.
INFLUENCE: The Psychology of Persuasionamazon.com
Robert B. Cialdini, Ph.D
ISBN 0-688-12816-5
Chapter 1 : Weapons of Influence
pp 11-14