A week or so ago, my wife and I were browsing in a second-hand shop when we came across a beautiful pine corner unit that was perfect for our newly-restored living room.

Being cautious, we decided to think it over and return in a few days' time.

When we did, we discovered that the unit had been reserved for someone else. We had lost the sale. And we now wanted it more than ever.

In our Negotiating Skills courses at ManageTrainLearn, we train people to use this tactic consciously. As an example of how it's done, we show how Eskimo hunters get the best price for their hides from their traders by downplaying the value of their hides, even to the extent of pretending that their furs are not worth looking at. Fearing that they won't get them, the traders are more desperate to buy and so increase what they are prepared to offer.

A similar trick of reverse psychology is played by Tom Sawyer in Mark Twain's book of the same name.

The young Tom has been conscripted by Aunt Polly to whitewash a 30 foot long, 9 foot high fence and, being work not play, he is not in the least interested. Moreover, Tom hates the thought of being ridiculed by his friends.

So, he hits on a plan.

As each boy passes by on the lovely Summer's morning, Tom pretends to be doing something that no other boy gets to do. He builds up the specialness and importance of his task so much that not a single boy can resist begging to have a go at it. And they're even willing to pay for the privilege.

Naturally, Tom leads them on so that (a) he reluctantly lets each boy have a go at the job, only, of course, on condition that they do it in the very special way that it's supposed to be done, and (b) extracts a good swap from each boy in the process.

Very soon, while Tom idles in the sun with his bounty of swaps, the long fence is painted by a procession of boys who can't wait to accept the new challenge and the new experience.

Mark Twain adds, "And Tom discovers, without knowing it, a great law of human action, namely that in order to make a man or boy covet a thing, it is only necessary to make it difficult to attain."

I don't suppose I'll ever know if the Reserved Sale sign on our pine unit was a ploy for a sale. However, just a few days later, the shop rang to say that their sale had fallen through and we could now have it.

Naturally, like fur traders, and boys in the American South, we couldn't wait to snap it up.