This article is the second in a series about Robert Cialdini’s book Influence: The Psychology of Persuasion. In that book, Cialdini identifies several of what he calls “weapons of influence” – sales techniques that are able to trigger an almost mindless compliance from people due to their alignment with psychological vulnerabilities that most of us share.

Perceptual contrast

If we see two things in sequence that are different from one another, we will tend to see the second one as more different from the first than it actually is. This is called perceptual contrast.

Cialdini presents a number of examples to demonstrate perceptual contrast in action. For example, if you lift two objects – a heavy one first and then a light one – you will probably estimate the weight of the second one as lighter than if you had just lifted it by itself.

A realtor or car salesman might show us a unit that is overpriced and in poor condition before showing us the one they really want us to buy. By contrast, the second one looks like a great deal and we want it more.

I came across a technique that engaged the contrast principle while I was investigating, undercover, the compliance tactics of real-estate companies. To “learn the ropes,” I was accompanying a company realty salesman on a weekend of showing houses to prospective home buyers. The salesman – we can call him Phil – was to give me tips to help me through my break-in period. One thing I quickly noticed was that whenever Phil began showing a new set of customers potential buys, he would start with a couple of undesirable houses. I asked him about it, and he laughed. They were what he called “setup” properties. The company maintained a run-down house or two on its lists at inflated prices. These houses were not intended to be sold to customers but to be shown to them, so that the genuine properties in the company’s inventory would benefit from the comparison. Not all the sales staff made use of the setup houses, but Phil did. He said he liked to watch his prospects’ “eyes light up” when he showed the place he really wanted to sell them after they had seen the run-down houses. “The house I got them spotted for looks really great after they’ve first looked at a couple of dumps.”

I notice the strategy I generally use when I’m asking for something I want is to pare down the request to something that seems reasonable – something I think I can get a “yes” for. Apparently that instinct may be incorrect. If instead I were to ask for something huge first, I would activate the weapon of “perceptual contrast”. If I were to then ask for what I really wanted it would seem small, reasonable, and trivially easy by comparison.

A corollary principle is that once you have already agreed to something large, additional items that are added seem smaller by comparison. Sales professionals use this technique to sell you options and accessories to large ticket items you have already purchased.

Again, my instinct is to keep requests simple and just ask for the big thing I really want. But perhaps that too is exactly the opposite of what I should be doing. Apparently the time when I get myself or others to agree to a large request is precisely the moment when my ancillary requests would be most likely to look small and easy to grant.

Personal marketing example

How could we use perceptual contrast in our own advertising campaigns? Would it be possible to use the power of this weapon on ourselves, even though we know what we’re up to?

Let’s say the goal I have is to go for a half hour walk three times a week. I could design a much more ambitious exercise program and show myself motivational reminders of that for a couple of weeks first. If I actually did that exercise program it would be a bonus, but the real objective of the campaign would be to create contrast, so that when I backed off to the second ad campaign that advocated walking 3 times a week it would seem easy by comparison.

There is one caveat to this method: the huge thing has to be believable or it won’t work. So, for example, if my initial campaign was for spending two hours in the gym every day and I know there’s no way I’ll do that, I would be inclined to blow the whole thing off as ridiculous. A more credible first offer might be to walk for an hour every day. I could combine images of myself walking with text messages like “I feel great because I walk for an hour every morning.” After running this campaign for a couple of weeks I could then substitute a similar campaign for my real objective – walking three times a week.

Another way we might use the contrast principle is to run several simultaneous ad campaigns – all of which we mean – but one is for a hard thing and several are easy. This is a strategy I’ve used with a lot of success. You know how when you need to finish a difficult project a lot of other chores like organizing your desk suddenly seem easy to accomplish by comparison? It’s like that. So I often include images in my screensaver slideshow or Google Sidebar Photos gadget to remind myself to follow up on easy things things like taking a class or ordering a book and they almost always get done.

The perceptual contrast method can be used in combination with several of the other techniques in Influence: The Psychology of Persuasion. It’s closely related to a weapon called Reciprocation, which we’ll look at in the next article.

Other articles in the psychology of persuasion series

1. The psychology of persuasion – because
2. The psychology of persuasion – perceptual contrast (you are here)
3. The psychology of persuasion – reciprocation
4. The psychology of persuasion – consistency
5. The psychology of persuasion – social proof
6. The psychology of persuasion – liking
7. The psychology of persuasion – authority
8. The psychology of persuasion – scarcity

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• How to rotate picture ads with the Google Photos gadget
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• How to send yourself text messages with Backpack
• How to write an effective ad on a Post-It note